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Fairbanks’s air quality issues began in 1901, when shallow water grounded a Gold Rush entrepreneur.

That August day, when a hired steamship could take them no farther up the Chena River, E.T. Barnette and his wife found themselves deposited on a sandy shoreline in the middle of Alaska.

Gold miners soon found Barnette had sacks of flour, sugar and coffee. Barnette then decided this was a pretty good place for his trading post, one he had hoped to build a few hundred miles away in Tanacross. Alaska’s northern urban center of Fairbanks was born.

Back in 1901, Barnette did not know this river valley has one of the strongest temperature inversions on the planet and some of the calmest winds in Alaska. Nor did he know that a spike in oil prices a century later would inspire so many people to start burning wood to help heat their homes. He did not imagine tiny particles in the air would some day make the city, on its worst days, have air as thick as Beijing’s.

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Uma Bhatt remembers summers in Fairbanks when she could open a package of crackers, leave it unsealed, and find them in a near-identical state a few weeks later. Those crackers now seem to lose their snap in just a few days.

 

An atmospheric scientist at UAF, Bhatt gave a recent talk on a rainy October day in which she mentioned the humidification of the Arctic, a region often as dry as a desert.

 

“As the sea ice has gone away, moisture is replacing temperature as the most important variable,” she said.

 

The ice that floats on top of the Arctic Ocean has been shrinking in extent for decades, with a much sharper slope of decline since 2000. Not only has northern ice covered less ocean, it has also become thinner, which allows it to melt faster.

 

Right now, as we enter the cold season, much of the ocean surrounding Alaska is up to 3 degrees Celsius warmer than normal.

 

“New ice is not… read more

For the past century, official thermometers scattered around Alaska have shown a warming trend. Most of the trusted weather stations are in river valleys; Gulkana, at 1,300 feet, is the high point of Alaska’s 21 “first order” weather stations, some of which have been running for a century.

 

But what about the weather up high? A scientist recently found evidence for even greater warming within the snows of Mount Hunter, sampled at a 13,000-foot saddle. Mount Hunter shoulders up next to Denali and Mount Foraker in Denali National Park.

 

In 2013, Dom Winski of Dartmouth College spent a few weeks living on Mount Hunter’s high plateau. He and a team from Dartmouth, the University of Maine and the University of New Hampshire twisted a hollow drill bit into ice and snow on top of the mountain. 

 

That summer they pulled out two cores of snow and ice, each in segments that added up to more than 600 feet. They transported all that ice back to a… read more

For the past century, official thermometers scattered around Alaska have shown a warming trend. Most of the trusted weather stations are in river valleys; Gulkana, at 1,300 feet, is the high point of Alaska’s 21 “first order” weather stations, some of which have been running for a century.

 

But what about the weather up high? A scientist recently found evidence for even greater warming within the snows of Mount Hunter, sampled at a 13,000-foot saddle. Mount Hunter shoulders up next to Denali and Mount Foraker in Denali National Park.

 

In 2013, Dom Winski of Dartmouth College spent a few weeks living on Mount Hunter’s high plateau. He and a team from Dartmouth, the University of Maine and the University of New Hampshire twisted a hollow drill bit into ice and snow on top of the mountain. 

 

That summer they pulled out two cores of snow and ice, each in segments that added up to more than 600 feet. They transported all that ice back to a… read more

“Professor Fuller Drops Dead in Garden.”

 

So reads the headline in the Farthest-North Collegian newspaper of June 1, 1935. In the story, an unnamed writer described how the the wife of the only physics professor at the Alaska Agricultural College and School of Mines screamed when she found Veryl Fuller face down in his garden. He was 39.

 

Fuller left behind his Fairbanks-born wife Lillian and young twins Mary and Richard, as well as his unfinished study on the aurora borealis.

 

His was the first aurora experiment attempted in Alaska. Ninety years ago, scientists had hints the northern lights flared up when particles from the sun tickled gases in the thin air above their heads, but they didn’t know how high the aurora occurred above Alaska.

 

Fuller got the job of finding out. He was a dark-eyed, sensitive man who accepted a position at the Agricultural College and School of Mines in 1926. To get to Fairbanks from Ames, Iowa… read more

A person might think that since we get our maximum sunlight on the summer solstice (on or about June 21), we should also get our peak warmth then. The sun’s calling the shots, right?

Not entirely, said former Alaskan Martha Shulski, author of "The Climate of Alaska" and now climatologist for the state of Nebraska.

“Alaska is warmest a few weeks after the solstice,” she said.

A lag exists between the peak of solar energy input and the warmth we feel. It’s a phenomenon that also shows up in winter or when people’s pipes mysteriously freeze in May.

“You see (the lag) in a lot of different places,” Shulski said.

Temperatures peak several weeks after we get the most sunlight because the ground absorbs energy from the sun and releases it to the air. This longwave radiation from the earth increases after summer solstice because the ground is slow to release the potent solstice-time energy. The day the heat emitted by the surface starts decreasing is… read more

For a town of its size (4,300 people), Barrow receives more visits by scientists than anyplace in America. The northernmost community in the U.S. has hosted researchers since Army Lieutenant P. Henry Ray built a polar observatory there in 1882.

This different-than-anywhere-else place with fewer people than a one-stoplight town in Texas has attracted scientists from all over the globe. Why? Because Barrow has housing, electricity and is way north of the Arctic Circle.

Those features led to the Arctic Research Laboratory being built in 1947. Today, Barrow hosts the Barrow Arctic Science Consortium, the Barrow Environmental Observatory, the NOAA Barrow Observatory and the Atmospheric Radiation Measurement Climate Research Facility.

Some scientists live in Barrow. Many others fly in from other places to study sea ice, whales, frozen ground, a vast underwater canyon just offshore, snow and other northern features.

All those instruments and people were in a… read more

In late July, more than 300 wildfires are burning in Alaska. With burned acreage totals one month ahead of the historic 2004 fire season, summer 2015 is again the year of the wildfire.

Many scientists are not surprised. In papers written a few years ago, Alaska researchers and others suggested smoky years like this one will be the norm for a few decades as hardwoods replace the spruce of Interior Alaska. The boreal forest, a swath of spruce-dominated woods from Interior Alaska to the Atlantic Ocean, might be in for a big change.

"Results suggest that a widespread shift from coniferous to deciduous vegetation began around 1990 and will continue over the next several decades," wrote UAF researcher Dan Mann in a paper published in 2012. "Our modeling results support previous inferences that Alaska's boreal forest is now shifting to a new ecological state."

And what might that state be? Terry Chapin of UAF wrote in 2004 that with an increase of temperature of 2… read more

A scientist named Victor Hessler once made an aurora detector by driving two metal rods in the ground a few hundred feet apart and stringing a wire between them. When voltage changed along the wire, a bell rang. Hessler then pulled on his boots and went outside to take black-and-white aurora photos.

During the recent St. Patrick's Day geomagnetic storm, people all over North America became aurora detectors. They used tools that weren't imaginable when Hessler was looking up in the 1930s. Aurorasaurus.org lit up with tweets and messages during those hours of turbulent, lovely space weather, producing a sort of "nowcast" for the northern lights.

That's one of the goals of the site's creator, Liz MacDonald. She's a space physicist at NASA Goddard Space Flight Center in Greenbelt, Maryland. Her dream, after a 2011 solar storm that produced red auroras visible from Alabama, was to enlist people as aurora observers using social media.

"I had heard of Twitter, so I… read more

SAN FRANCISCO -- At this annual gathering of more than 20,000 Earth and space scientists, press conferences offered by the organizers feature scientists discussing everything from Mars rovers whiffing methane to Christmas lights visible from space. One press conference that has for a few years had a recurring slot at the fall meeting of the American Geophysical Union is the state of changes in the Far North.

Here's some highlights from that and a few of thousands of science bites offered at the fall meeting of the American Geophysical Union. The meeting is held every December in San Francisco.

The dark waters of the entire Arctic Ocean have absorbed the sun's rays at a rate that has increased five percent since 2000, detectors on satellites have shown. No other place on Earth is showing a similar increase in absorbing solar radiation, said Norman Loeb of NASA's Langley Research Center.

The Beaufort Sea north of Alaska and western Canada has absorbed heat at a… read more

It's mid-October, 118 miles from the Arctic Circle. Time for a walk to work.

Since I last wrote about my three-mile commute through the raindrops of August, the 1,100 acres of boreal forest between my house and the university has undergone the most drastic change of the year. Ankle-deep snow covers the North Campus and most of Interior Alaska.

Steps on the forest floor, which sinks like a frozen piecrust, are silent. The wet snow soaked the crunch out of leaves. It's quieter still because thousands of bodies have moved on from their temporary occupation of the spruce. The kinglets, warblers, thrushes and even the lagging juncos have made their final leaps from northern branches.

Now, one hears only the locals on the North Campus: redpolls, pine siskins, chickadees, grosbeaks and ravens. It's possible that tundra swans — the last of the migrants to exit the dining room — are arcing overhead. But the forest has returned to its most common mode. This snow may… read more

TOOLIK FIELD STATION -- Despite a wind that makes today’s minus 14 degrees Fahrenheit feel like minus 39, a worker at this research camp in blue-white hills north of the Brooks Range has proclaimed this the first day of summer.

Today, the population of Toolik Field Station increases from nine -- five people running the camp, three scientists and me -- to 16. Seven support staff members are making the 10-hour drive north from Fairbanks. Starting tomorrow, Toolik Field Station will be in summer mode until September. During the next few months people will sleep in dorm-style buildings, weatherports and tents as they study ground squirrels, permafrost, plants, fish and other far-north mysteries. At the peak of action here in mid-July, more than 100 scientists will clomp the gravel in rubber boots.

People have pondered things here on the treeless tundra since 1975, when the National Science Foundation funded research on nearby Toolik Lake, a splotch on the map that takes… read more

It’s mid-February, 118 miles from the Arctic Circle. Time for a walk to work.

The trail through the boreal forest is right outside my door. The North Campus of the University of Alaska Fairbanks is 1,100 acres of spruce trees, ski trails, two lakes, an exotic tree plantation and a few dozen subtle research projects. Some are humming, twirling, measuring. Others are stained by leaf litter, falling back to the soil.

On a campus of about 2,250 acres, only 10 percent is roads, parking lots and clusters of buildings. My office and destination is in one of these developed areas called West Ridge. A north-facing window there provides a view of the same forest I see looking south from the kitchen table. The North Campus is quiet enough that if I see any creature except a raven during a morning commute, it’s a surprise.

Some days, like this one, are cold enough that I walk in rather than ski. A trail designated for dog walking offers the straightest line, just more… read more

Painting the breeze one dozen at a time, monarch butterflies once fluttered across the meadow of James Hansen’s Pennsylvania farm. Now, the climate activist and his wife are lucky to see one. Monarchs are threatened by lack of the only food — milkweed — they eat as caterpillars. Herbicides, land clearing and other people-related activities may be dooming the monarchs.

“I wonder if we are witnessing the extermination of a species,” Hansen, the 73-year-old longtime NASA researcher said to a crowd of about 3,000 people in San Francisco’s Moscone Center. Hansen was the headline speaker at the Fall Meeting of the American Geophysical Union, attended by more than 20,000 scientists in December 2013.

Hansen used “extermination” for its implication that people have a choice on some matters, such as the survival of more complicated species.

“There is still an opportunity for humanity to exercise free will,” he said. “It’s still possible to get on a different path, but… read more

In warm Alaska summers like this, in which Fairbanks has set a record for most 80-degree Fahrenheit days and Anchorage has exceeded 70 with similar frequency, rainfall has been a phenomenon many people have not missed.

But even though we are a species that scurries when water falls from the sky, rain is more essential to our survival than pleasant, dry breezes. Rain is, after all, the free distribution of a substance more valuable than gold. And, despite places like Southeast’s Little Port Walter — where residents endure 80 days each year with precipitation amounts greater than one inch, most of it in the form of rain — most Alaskans don’t get much of it.

Especially when you consider Mount Waialeale in Hawaii, where it rains more than an inch every single day. Or Cherrapunji, India, which experienced more than 1,000 inches of rain from August 1860 to August 1861.

As for daily deluges, it’s hard to beat Reunion Island, located in the Indian Ocean east of… read more

On cold winter nights long ago, Harvey Gilliland of Petersburg sometimes woke to the buzz of an alarm mounted on the wall of his kitchen. He kicked off the blanket, got dressed, pulled on his rubber boots, and strolled three city blocks to the building in which he worked.

After Gilliland, an electronics technician, twisted a few knobs to restore normal power to an underwater communications cable, the buzzer stopped. The noise was there to alert him to excessive current on the cable’s power system.

On his walks back home, he wondered what might have caused the alarm. On a few of those nights when the sky above Southeast Alaska was clear, he would see the aurora borealis on his return home. Sometimes it was dramatic enough that he woke his wife and two kids and suggested they look up.

“Three or four times a year I had this experience,” Gilliland said recently over the phone from Petersburg. “I though it was kind of unique to have my own aurora alarm.”

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On a cool spring morning in the mountains of southwest Washington, 12-year old Cathy Cahill helped her dad plant scientific instruments around the base of trembling Mount St. Helens. A few days later, the volcano blew up, smothering two of his four ash collectors. When he gathered the surviving equipment, Cathy’s father found a downwind sampler overflowing with ash laced with chlorine. Tom Cahill of the University of California, Davis, wrote a paper on this surprising result; editors at the journal Science were impressed enough to publish it.

Tom’s teenage daughter was not a co-author on her dad’s Mount St. Helens paper in the early 1980s, but her name has appeared next to his in a few journals since then. Now 44, Cathy continues to stamp her own mark on the field of atmospheric science. The University of Alaska Fairbanks professor has captured and examined the particles floating in air breathed by U.S. servicemen and woman in far-off deserts. She has invented an air-sensing… read more

You may not have noticed it as you were scooping fish out of the Copper River or riding your bike through the tawny light of 10 p.m., but Alaska just made a left turn toward winter.

Much of the state will soon reach the average yearly date when the air won’t get any warmer. In Fairbanks, on July 19 the average daily temperature based on about a century of records drops from 63 to 62. Anchorage, because the ocean is nearby, starts cooling later, on July 29, when the average temperature drops from 59 to 58. Chandalar Lake reached its heat peak about July 15. Adak and Shemya in the Aleutians are two of the last places in Alaska to give in, with their average temperatures not dropping until late August and early September.

A person might think that since we get our maximum sunlight on the summer solstice (on or about June 21), we should also get our peak warmth then. The sun’s calling the shots, right?

Not entirely, said Martha Shulski, formerly of the Alaska… read more

On the 5-mile snowmachine ride up to Point Barrow, we saw several fresh polar bear tracks the size of dinner plates, a pile of whalebones from last year, and a 3-foot-wide crack in the sea ice that could swallow a sled. The crack was created when an ice floe in the open water crashed into shore-fast ice.

It was masked in a snowdrift, and our guide Brower Frantz nearly fell into it.

Frantz’s job is to spot and avoid hazards like these. He is a bear guard and supervisor for UMIAQ.LLC, a Barrow-based company that provides field logistics to researchers and other groups. His task this week is to keep a group of University of Alaska Fairbanks researchers safe as they drill, slice, probe and travel on sea ice off the coast of Barrow.

Frantz can pick up tracks out of the corner of his eye while cruising on a snowmachine through a world of white.

“We grew up this way, and tracking is definitely one of the keys to success in our subsistence way of life. So… read more

In Alaska, our lives revolve around the weather. When it comes to predicting conditions like temperature, snow and rain, the best glimpse into the future comes from climate models.

But standard climate models are very broad—looking at how global climate will be affected by things like escalating carbon dioxide emissions.

In a land of permafrost, icefields, massive mountain ranges and rainforest, a more nuanced prediction is helpful. For example, will it get rainier in the North Slope over the next few decades? When might Southcentral’s epic snow dumps turn to rain?

Steph McAfee recently produced a dataset that imposes high-resolution data from weather stations onto global climate models of the future to try to predict Alaska’s climate with more precision. It gives detailed projections for snow in different regions of the state over the next century.

“It brings the data to a spatial scale that is more accessible and useful,” says McAfee, a climatologist… read more

On a clear, cold night two winters ago in Fort Yukon, Carl Andersen watched a rocket he helped design pierce the upper atmosphere. He and three other scientists shot pictures as the rocket ejected bright puffs of chemicals in an inverted V formation more than 60 miles up.

“They were the brightest things in the sky,” Andersen said from his office at the University of Alaska Fairbanks.

Other scientists watched the puffs drift across the sky from Toolik Field Station in the Arctic and from Poker Flat Research Range, UAF’s sounding rocket range 30 miles north of Fairbanks. They would piece together thousands of images from the three locations to track the chemical tracers against the star field to calculate their position and measure atmospheric conditions.

“We’re taking a “very short but very accurate close-up picture of the winds,” Andersen said.

They were testing out a new payload design, which is the package of scientific instruments attached to the… read more

An April snowstorm whirling outside my window today seems to be announcing the postponement of spring. As I sit here watching the show, it makes me think back to the shortest summer ever.

In 1992, it snowed more than 9 inches on May 12th. A string of 70-degree days that followed ate that up in a hurry, but the snow returned in early fall. By September 13th, more than one foot of snow cushioned the ground, and leafed birch trees arced under the weight of ice crystals. Twenty-one years later, some trees still bow to that memory.

I wondered if 1992 was the best example of a year without a summer. The perfect man to ask is Rick Thoman of the National Weather Service. Besides having an encyclopedic memory of Alaska weather events, after 20 years as lead forecaster in the Fairbanks office, Thoman just started a new job as the Weather Service’s Climate Science and Services Manager.

As usual, he sharpened my memory.

“Ninety-two was actually a warm summer,… read more

Forty years ago, an Army helicopter pilot flying over a tundra plateau saw a group of caribou. Thinking something looked weird, he circled for a closer look. The animals, dozens of them, were dead.

The pilot reported what he saw to the Alaska Department of Fish and Game. The caribou, 48 adults and five calves, were lying in a group. The way their carcasses rested showed no signs that the animals had been running from a predator.

As word spread of the 53 dead caribou, people speculated what might have killed them: Nerve gas, toxic waste or some other dark secret from the Army post nearby, flying saucers?

The Alaska Department of Fish and Game sent wildlife disease specialist Ken Neiland to the site, about 33 miles southwest of Delta Junction. Glenn Shaw, a young atmospheric scientist from UAF’s Geophysical Institute, went with him. Shaw had studied lightning before.

From the air, the scientists saw a clue to the animals’ death, a giant “Lichtenberg… read more

Sometimes, after idling in the sky for hours as a greenish glow, the aurora catches fire, erupting toward the magnetic north pole in magnificent chaos that can last for three hours. “Substorms,” as space physicists call them, can happen two or three times each night.

The man who came up with that name half a century ago has, with a former student he once mentored, come up with a new theory on the location of heavenly energy for these auroras.

Syun-Ichi Akasofu first heard the word aurora from his mother, who sang it to him in a lullaby. He would not see the phenomenon until he was 28, when in the late 1950s he traveled from Japan to the Geophysical Institute at the University of Alaska Fairbanks. He has been here ever since.
 
During much of his six decades in the far north, he has pondered the complicated mechanisms that trigger the aurora. But there was a 20-year gap in Akasofu’s academic pursuits when he served first as director of the Geophysical… read more

This just in: 2012 was the coldest year of the new century in Fairbanks, and the second coldest here in the last 40 years.

Fairbanks isn’t the only chilly place in Alaska. Average temperatures at 19 of 20 long-term National Weather Service stations displayed a cooling trend from 2000 to 2010, according a recent study written up by Gerd Wendler, Blake Moore and Lian Chen of the Alaska Climate Research Center.

The rest of the world has not been going Alaska’s way. For the 36th consecutive year, the yearly global temperature in 2012 was warmer than average. That temperature, calculated from satellite data by researchers with NASA’s Goddard Institute for Space Studies, was about 58.3 degrees Fahrenheit (Fairbanks’s was 24.1 degrees F).

During the first decade of the 2000s, Alaska bucked the global warming trend, though the temperature variations were so slight you might not have noticed. Except during winter, when most of the cooling occurred. One example was… read more

The White River Ash, blasted from giant eruptions somewhere in today’s Wrangell-St. Elias Mountains, drifted as far away as Ireland and Germany, said experts who attended the December 2012 Fall Meeting of the American Geophysical Union, held in San Francisco.

Ash from the White River eruptions, possibly from 15,638-foot Mount Churchill or at least close to it, left an easy-to-see mark on eastern Alaska and northwestern Canada. Explorer Frederick Schwatka documented the ash in 1885 in his book “Along Alaska’s Great River.” People driving the Klondike Highway pass more than two feet of the whitish grit exposed in road cuts on their journey through the Yukon Territory.

“It was an enormous eruption,” said Britta Jensen of the University of Alberta in Edmonton.

Jensen studies volcanic ash layers in northwest Canada and Alaska. Recently, she and Duane Froese, also of the University of Alberta, along with colleagues in the United Kingdom, connected the dots on some… read more


Here we go again. Early this week, a friend at the National Weather Service pointed to a swath of sub-zero temperatures across a map of northern Alaska. The low temperatures were anchored by minus 27 degrees Fahrenheit at the always-frigid Chandalar Lake weather station.

But, just as we begin to wince from the cold, we experience one of the best light shows of late fall and early winter. Fairy dust wafting down from the sky turns the passing ravens into Tinkerbells as they fly through glittering shafts of light. The sun, sitting low on the horizon, seems to be wearing a white Mohawk as rainbow shields hang in the air on either side. The mystical parentheses are pointed to by kids in cars and admired by people looking out south-facing windows.

These phenomena, caused by fine ice particles called diamond dust, have been… read more

Arctic haze, a blob of dirty air that fuzzes up Alaska views in springtime, seems to be losing its punch.

By comparing air measurements in Barrow from the 1970s to 2008, scientists have found that pollution particles from factories in Russia and Eurasia have become fewer and fewer in the last 30 years.

“The Arctic haze is disappearing,” said Glenn Shaw, who did pioneering research on the phenomenon and is the co-author on a recent paper about its decrease. “We don’t know why.”

Shaw, a professor emeritus at the University of Alaska Fairbanks’ Geophysical Institute, has in years past stopped passersby to point out how Arctic haze—pollution particles in the air that scatter light—has “obliterated” views of the Alaska Range in springtime. In recent years, he has noticed that the vistas have been much clearer from Fairbanks, and instrumentation in Barrow seems to back that up.

“There’s less of the industrial signal, of what’s typically been known as Arctic… read more

It’s a slow season for aurora watchers, due to an extra-long quiet period on the great aurora generator—and all-around giver of life—the sun.

“For two years we’ve been in an unusual, very low, extended solar minimum,” said Dirk Lummerzheim, an aurora forecaster at the Geophysical Institute at the University of Alaska Fairbanks. “That has an effect on aurora because aurora activity follows solar activity. The aurora hasn’t been too exciting lately.”

Like the booms and busts of snowshoe hares, the numbers of both solar flares and sunspots (dark splotches on the sun) peak about every 11 years. On the other side of that peak is a crash, and the sun has bottomed out in sporadic activity since early 2008. The sun has gone more than two years without spewing a significant solar flare, and sunspot counts have also been very low. And sunspots are not great aurora indicators anyway.

“There’s a statistical connection, but the appearance of a sunspot doesn’t guarantee… read more

Dorothy Ivanoff of Unalakleet isn’t crazy about flying, especially when the flight is bumpy. That’s why she surprised herself in early August, when her commercial pilot circled near the village of Koyuk so they could better see a funnel cloud developing on Norton Sound.

“Oh my god, this thing was spectacular,” she said. “I wasn’t scared or nervous at all.”

Ivanoff used the video mode of her point-and-shoot Canon camera to record more than one minute of a waterspout that danced across the surface of Norton Bay near Koyuk in early August. She posted it on YouTube here: http://www.youtube.com/watch?v=crdtbZwpHbY.

Ivanoff recorded something few Alaskans see. A few years ago, a National Weather Service meteorologist listed 43 tornado-like events being reported in Alaska, among them 18 waterspouts, rotating columns of air that form over large bodies of water. Waterspouts like the one Ivanoff saw have probably been seen by dozens of Alaskans who haven’t reported… read more

Alaskans have seen wacky weather extremes in the first month of 2009, from an enduring cold spell to a chinook wind a few days later that splashed much of the state with warm air. If that change was a shock to humans, what were the effects on other life forms in the North?

Before exploring that question, here are a few examples of the seesaw weather. In the Interior, the National Weather Service cooperative station thermometer at KJNP radio station in North Pole registered a low of minus 58 degrees Fahrenheit on Jan. 3, according to Rick Thoman of the NWS in Fairbanks. On Jan. 16, the same thermometer read plus 55 degrees.

In Anchorage, temperatures varied from minus 31 degrees Fahrenheit at Campbell Creek Science Center Jan. 7 to plus 52 degrees at Merrill Field Jan. 16. Chinook winds that topped 100 mph in some areas also ate a good portion of snow in the Anchorage Bowl, according to John Papineau of the Anchorage office of the NWS. The snowpack at his office on… read more

Rod Boertje knew it was getting cold when the National Park Service took the dogs inside. Boertje, then a graduate student in wildlife biology at the University of Alaska, was doing a study on caribou in Denali National Park in the early 1980s. Park rangers, saying it was too cold for the sled dogs that had brought Boertje to his study area, mushed the dogs back to a warm kennel. Boertje stayed behind, watching caribou to see what they did in the winter. He’s one of a few scientists who have done field work in Alaska on the coldest days of winter.

Boertje, now a biologist for the Alaska Department of Fish and Game, brought three thermometers with him on his graduate study. He confirmed minus 60 degrees Fahrenheit, while he and another student watched caribou in a valley below.

“It was real marginal,” he said. “You put on all the gear you had to sleep, then got into your 40-below bag. There was still no way to keep warm unless you were moving.”

Boertje says he… read more

It is gray and raining and chilly and I want some coffee. I’m driving south from Fairbanks, wondering when I have seen a wetter few weeks in Interior Alaska. No past episode is coming to mind.

I’m probably forgetting a time or two, but I know a few things: the town of Nenana has water in its streets, four-wheelers are floating upside-down in Salcha, and the islands and gravel bars have disappeared on the big river (Tanana) and the smaller river (Chena).

The gray and silty Tanana River, fed by melting glaciers, rainfall, and snowmelt all the way to the Canada border, is as wild as the day the earth tilted enough for it to start flowing. But the Chena River has a manmade throttle built after the great flood of 1967, when the Chena oozed over its banks and turned Fairbanks into a lake. I want to see this device at work.

I’m off to the Chena River Lakes Flood Control Project. In the 1970s, the U.S. Army Corps of Engineers moved mountains of damp earth and left… read more

My dad never liked the heat. On humid days in upstate New York, he’d ride out hot spells by sitting in his underwear in front of an electric fan. He got no relief on his only trip to Alaska, when two days of 90-degree June temperatures forced him to hunker down inside my small cabin.

Recent cool temperatures got me to thinking that I hadn’t seen a 90-degree day in a fair chunk of time. But my memory is among the wobbliest of datasets, so I turned to a professional. According to Eric Stevens at the Fairbanks Forecast Office of the National Weather Service, more than a decade has passed since Fairbanks, one of the warmest places in Alaska, reached at least 90 degrees Fahrenheit.

“August, 1994,” Stevens said over the phone, remembering the last time Fairbanks reached 90 degrees. “This is the longest stretch of no-nineties in the Alaska climate record, since 1904.”

Fairbanks reached 93 degrees on Aug. 5, 1994, and hasn’t reached 90 degrees in the 14 years since.… read more

OHydrologist Ed Plumb of the National Weather Service in Fairbanks was out measuring ice thickness on the Chatanika River last week. On his drive to a valley north of Fairbanks, he kept his eye on an outdoor thermometer attached to the truck.

As he crested Cleary Summit, the thermometer read 44 degrees Fahrenheit. He watched the temperature drop as he descended toward Chatanika Lodge, where the thermometer read minus 2 degrees. That temperature difference, caused by an extreme temperature inversion, occurred over a distance of about seven miles when Plumb dropped from a height of about 2,200 feet on the hilltop to 713 feet at the valley bottom.

Temperature inversions — where air temperature increases with elevation — happen in calm, windless places such as Interior Alaska. With no wind to mix the atmosphere, not much sunlight to heat the surface and a snow-covered surface that reflects sunlight, cold air tends to pool in low places and stay there. Fairbanks often has… read more

On December 8, 2006, in the middle of Alaska, the air temperature on the roof of the Geophysical Institute at the University of Alaska Fairbanks is 37 degrees Fahrenheit. The normal high temperature for this date is 5 degrees. A chinook wind is blowing over Alaska.

Chinook winds happen when rivers of warm air flow over mountain ranges, in this case the Alaska Range. Also known as “snow-eaters,” Chinooks happen several times each winter in Alaska, but rarely do they have enough punch to melt large amounts of snow. A notable exception was the December of 1934, which featured the only green Christmas in the 100-year weather record of Fairbanks, and all-time high temperatures in Anchorage and Nome.

At the beginning of December 1934, Fairbanks had five inches of snow on the ground (in 2006, another lean year, there’s also only five inches). On December 3, 1934, the airflow known as a jet stream shifted to flow from south to north, bringing warm, moist air from the North… read more

The blackened scars that Alaska fires leave on the landscape may result in more lightning, more rain in some areas just downwind of the scars, and less rain farther away, according to two scientists.

Nicole Mölders and Gerhard Kramm, both of the Geophysical Institute at the University of Alaska Fairbanks, study how changes in landscapes affect the weather. After Alaska’s fire season in 2004, when smoke befouled much of the air Alaskans breathed and a collective area the size of Vermont burned, the scientists wondered how all that charred country would affect local weather patterns.

The researchers used MM5, a computer model based at Penn State University and the National Center for Atmospheric Research, to simulate conditions on the ground and in the air above it. They compared the surface of Alaska before and after Alaska’s record fire season, in which 6.72 million acres burned. The model told them that fire scars larger than 250,000 acres—about the space taken up by… read more

As one of the aurora forecasters at the Geophysical Institute located on the University of Alaska Fairbanks campus, Charles Deehr has emailed people around the world who want to know when the northern lights will appear above their heads. Some requests catch him by surprise, such as this springtime note from a supervisor for an Anchorage taxicab company who said the aurora was affecting his ability to communicate with cabbies:

“I don't expect your website to continue to post the ‘Auroral Forecast’ (during the summer) just for Alaska Cab, but you may not be aware that some companies access this information for business purposes. For us, I monitor your website and a NOAA space weather site so that I will know if such things will be affecting our computer system communication between our office and the cabs in the city. ”

Sometimes the aurora messes with the radio waves used in communications systems. My employer, the Geophysical Institute, exists in a large part… read more

South of Donnelly Dome at midnight, Jim Brader pushed open the pickup door. He turned on his headlamp and pointed a wind gauge into a gale that sounded like a freight train. Brader, a National Weather Service meteorologist, yelled out:

“Gusts to 42 miles per hour at eye-level, probably 50 or 60 just above our heads.”

Brader had found the heart of a chinook—a warm, dry wind that floods Interior Alaska several times each winter, often driving temperatures 40 degrees warmer than average.

Chinook is a Pacific Northwest Indian word meaning “snow-eater.” The strongest chinook recorded in Fairbanks ate most of the town’s snow in early December 1934, when temperatures rose above 50 degrees Fahrenheit for five straight days.

Chinooks happen anywhere winds force moist air over a mountain range. As the air meets a mountain range, the air rises, cools, and often dumps its moisture as rain or snow on the windward side of the mountains. As the air tops the… read more

Lightning, long thought to have a fondness for high ground, may instead have a thing for the boreal forest. At least that's what University of Alaska researchers who track lightning strikes are finding.

Because lightning is responsible for most of the acreage burned in Alaska every year, Bureau of Land Management technicians installed lightning sensors at Unalakleet, Bethel, Galena, McGrath, Tanana, Bettles, Ft. Yukon, Fairbanks and Tanacross. Most of the sensors are in the Interior because that's where the vast majority of lightning strikes happen.

Dorte Dissing and her academic advisor Dave Verbyla, both of the UAF department of forest sciences, use BLM sensors to track lightning strikes. While working on her Ph.D. degree, Dissing and Verbyla noticed that dots on a map representing lightning strikes neatly covered the range of boreal forest in Alaska. Boreal forest consists of spruce, birch, aspen, willow and other trees. The area in Alaska covered by boreal… read more

For most of the year, Fairbanks, Alaska, defies meteorological logic. Unlike what happens in most places, Fairbanks temperatures often increase with altitude in the few thousand feet above the ground. The blame goes to one of the most powerful temperature inversions on the planet, a phenomenon measured by Rick Thoman with the National Weather Service Forecast Office in Fairbanks.

Thoman is a hill-dweller, living west of town in Lincoln Creek subdivision, about 1,600 feet above sea level. He’s compared temperatures at his home with those of a Weather Service observer who lives in the Goldstream Valley, about 590 feet above sea level and about 20 feet above Goldstream Creek.

Thoman gathered his statistics in interior Alaska’s season of strong temperature inversions, from October until about mid-March. These inversions, in which warmer air forms a lid that sits above cold air, happen in part because Fairbanks sprawls in the bowl of the Tanana Valley, which is hemmed in… read more

Alaska weather geeks, including me, will soon have more to gawk at. The state’s offices of the National Weather Service are switching to a new communication system that will someday allow people to check forecasts for their specific neighborhood or village.

Forecasters at weather service offices in Juneau, Anchorage and Fairbanks have started to use a computer database that divides Alaska’s 912,597 square kilometers into individual boxes about three-to-five kilometers on a side. As soon as the bugs are worked out of the system, Alaskans will be able to select specific areas of the state and get detailed forecasts.

“Say you want to go hunting 70 miles west of Iliamna and you want to know what the weather will be like in two days,” said Eric Stevens of the NWS office in Fairbanks. “Instead of settling for a generalized forecast for the entire region around Iliamna, you could click on a point on the map, and boom, there’s your customized information. We have the… read more

Fairbanks, Alaska experiences one of the most extreme temperature inversions on the planet. During a temperature inversion, hilltops are warmer than valleys as warm air traps cold air beneath it. To measure this phenomenon—which is caused by short days, low winds, and hills that form walls around a town—I rigged my car with an outdoor thermometer and enlisted Jim Brader to drive me around Fairbanks. Brader is a meteorologist with the National Weather Service Office in Fairbanks.

The digital thermometer attached to my ski rack read minus 28 Fahrenheit when I met Brader at his house near Creamer’s Field in Fairbanks. Creamer’s Field is a low spot in Fairbanks where cold air often pools in both summer and winter.

The temperature rose to minus 21 as Brader drove into the heart of Fairbanks at the corner of Cushman Street and Second Avenue. The rise in temperature might have been due to Fairbanks’ “heat island” effect, Brader said. Warmth leaking from buildings and… read more

While driving in a dense fog a few days ago, Matt Barkdull was able to look directly at the sun as it hung like a disc in the shaded portion of his windshield. While taking the rare opportunity to look at our closest star, he noticed a dark blotch on the sun’s face. A computer network manager at the International Arctic Research Center, Barkdull later described the spot to Syun-Ichi Akasofu, the director of the research center and one of the world’s foremost experts on the aurora.

Akasofu told Barkdull that he had seen a large sunspot, one that spits out solar flares resulting in auroras overhead in Germany, rare red auroras throughout the northern hemisphere, and disruption of high-frequency radio communications in the north. The solar flares that erupted from the sunspot included three of the largest flares scientists have seen in this new era of satellites.

Sunspots are cool, dark areas on the surface of the sun that… read more

As I watched a movie with friends recently, three dogs in the room suddenly began to act out their roles as house guardians by running to the windows and barking at a distant rumbling. We humans were puzzled until flashes in the cloudy night sky soon identified the intruder, and we walked out on the deck to enjoy a rare May thunderstorm.

As often happens when natural phenomena occur, questions were thrown at the nearest science writer: "what causes lightning and thunder?" and, "doesn't lightning strike from the ground up?"
Scrambling for the textbook Meteorology Today, I relearned that lightning is an electrical discharge identical in everything but size to the spark that jumps from your hand to doorknob in a carpeted room.

The lightning that most impresses us---that which strikes the ground---represents only about 20 percent of the lightning generated within a cloud. Most lightning strikes occur within a single cloud, while others reach from one cloud to… read more

April 2002 was the wettest April ever recorded in Fairbanks, with sticky blankets of snow invading what has been the driest month since people began keeping official records here in 1904. As springtime Fairbanks does its impression of August, it makes a person wonder: are there any fail-safe weather patterns in Alaska?

Interior Alaska has a few familiar but imperfect trends, according to meteorologist Jim Brader and hydrologist Eric Stevens, both of the National Weather Service office in Fairbanks:

Southwest flow and wet Augusts: In spring 2002, the jet stream, a high-speed ribbon of air that belts the globe and carries weather systems, tilted northward. The shift set the Interior up for "southwest flow," during which moist air follows a natural duct between the Alaska Range and Kuskokwim Mountains, falling out as rain or snow when it reaches the Tanana Hills surrounding Fairbanks. Southwest flow often makes August the wettest month of the year in… read more

For years, people have viewed the Arctic as the canary in the coalmine of global change: As the planet gets warmer, the north feels the heat first, and feels it with the most punch.

This long-held notion may not be true, according to a few scientists who devote their professional lives to studying the climate of the Arctic. By gathering historic temperature and sea-ice records from the northern end of the globe, the group has found that warming in the Arctic during the last century is about the same as for the rest of the northern hemisphere.

Igor Polyakov is the leading author on the new study, soon to be published in the journal Geophysical Research Letters. Polyakov, a research associate professor at the University of Alaska Fairbanks' International Arctic Research Center, is from St. Petersburg, Russia. His connection with colleagues at the Arctic and Antarctic Research Institute in St. Petersburg allowed the researchers to gather detailed weather observations… read more

South of Donnelly Dome at midnight, Jim Brader pushed open the pickup door. He turned on his headlamp and pointed a wind gauge into a gale that sounded like a freight train. Brader, a National Weather Service meteorologist, yelled out:

"Gusts to 42 miles per hour at eye-level, probably 50 or 60 just above our heads."

Brader and I had found the heart of a chinook-a warm, dry wind that floods interior Alaska several times each winter, often driving temperatures 40 degrees warmer than average. Chinook is a Pacific Northwest Indian word meaning "snow-eater."

The strongest chinook recorded in Fairbanks ate most of the town's snow in early December 1934, when temperatures rose above 50 degrees Fahrenheit for five straight days.

Chinooks happen anywhere winds force moist air over a mountain range. As the air meets a mountain range, the air rises, cools, and often dumps its moisture as rain or snow on the windward side of the mountains. As the air… read more

Climate change caused by people is a tough thing to measure in most places, but not in big cities. The clustering of humans, cars, pavement and rooftops makes some cities warmer than surrounding areas. Called "urban heat islands," they exist from Los Angeles to Atlanta to New York. Even Alaska has one.

A few researchers in Berkeley, California have devoted themselves to the study of heat islands. They've found that Los Angeles is 6 to 8 degrees Fahrenheit warmer than the surrounding areas. That may not seem like a lot, but those few degrees add up when you multiply them by the cost of air conditioning in millions of homes and offices.

The Heat Island Group, as the researchers call themselves, reports that intense heat absorbed by dark shingles can penetrate buildings, making air conditioners work harder. Members of the research group compared roof surfaces by painting one roof black and another white. The black roof was 70 degrees warmer than the air. The white roof… read more

When the lights go out in Georgia, Georgians call the electric company. When the northern lights go on in Georgia, Georgians call Alaska scientists.

The day following a display of aurora borealis that hovered above the Lower 48, the information office staff at UAF’s Geophysical Institute received 42 e-mail messages, including this one from a woman who lives in Clinton, Tennessee, near Knoxville:

“About 10:45 p.m. I went outside to feed my dogs, when I looked up in the sky and saw a creepy red glow with finger-like shapes.”

Martha Payne was one of many non-Alaskans who saw an aurora display on the night of November 5, 2001. People saw the aurora that night in California, Wyoming, Pennsylvania, Missouri, New York, Michigan, Nevada, Illinois, New Jersey, Maryland, Wisconsin, and scads of other places.

The November 5 aurora was the result of a major solar flare, an explosion on the sun that caused a shock front in the solar wind. The solar wind is a high… read more

Made visible by the return of dark nights, the aurora borealis is again performing above Alaska. The start of aurora-watching season comes at a good time for Syun-Ichi Akasofu, one of the world's foremost experts on the northern lights. He is now updating Aurora Borealis, The Amazing Northern Lights, a book published by the Alaska Geographic Society in 1979.

Akasofu is the director of the International Arctic Research Center at the University of Alaska Fairbanks. He has studied the aurora since 1958, when he arrived in Fairbanks from Japan with a pair of skis and a desire to learn all he could about the aurora borealis. In the 44 years since, he has helped unravel some of the aurora's mysteries.

In the new version of the aurora book, which Alaska Geographic will publish in 2002, Akasofu will include early explorers' written accounts of the aurora. He gathered most of their words 30 years ago. While his son attended piano lessons at the university every Saturday… read more

Mark Conde will soon become the envy of every boy who has ever set off an explosion in the backyard. Conde is a scientist who studies the aurora borealis; he will soon realize a lifelong dream by designing and launching his own rocket.

“This is the type of thing science nerds dream of getting to do,” said Conde, an aurora physicist at the Geophysical Institute at the University of Alaska Fairbanks.

This rocket is no toy. It’s 55 feet tall and has three chambers filled with explosive fuel. The rocket will have the power to penetrate the ionosphere, the thin air where the aurora resides from 60 to 500 miles over our heads.

Conde is a native of Tasmania, an island as separated from Australia in distance and mindset as Alaska is from the Lower 48. He came north to study the aurora borealis eight years ago. He could have stayed closer to home and studied the aurora australis, but the best place to watch the southern lights is on the ice of Antarctica, while in… read more

Steady rains this August have inspired conversations about 1967, when the Chena River spilled over its banks and flooded Fairbanks. For more than a week, the city core was underwater, and the town became a lake more than five miles wide. The flood forced thousands of people to leave the city and caused more than $180 million in damage to homes and businesses. Although a 1967-type flood will probably never happen again thanks to the Chena River Lakes Flood Control Project, August continues to be the wettest month in Alaska's Interior. The jet stream is to blame.

Eric Stevens, a hydrologist with the National Weather Service in Fairbanks, describes the jet stream as a high-speed ribbon of air circling the globe. The jet stream whips around the planet at speeds that reach 100 miles per hour, sometimes dragging weather systems with it.

In August, the jet stream shifts position; instead of belting Earth from west to east, it tilts northward. This shift leaves the Interior… read more

The world is becoming warmer according to thermometers all over the planet, shrinking caps of sea ice, disappearing permafrost and dozens of other indicators. How much warmer will Earth become? Computer models are helping scientists find the answer.

John Walsh with the University of Illinois was in Fairbanks recently to discuss climate predictions. He and other scientists combined the results of nine computer climate models to predict future conditions in the Fairbanks area and the Arctic Ocean.

The computer models predict that during the next 30 years, Fairbanks area temperatures will become 1 to 3 degrees Celsius warmer than they are now. In the next 90 years, area temperatures will rise as much as 8 degrees Celsius. The models foretell warmer winters in Fairbanks, which is consistent with recent scientific studies. The models also show a trend toward cooler summers in the late 21st century. Walsh said increased rainfall would be the cause; the sun is expected to… read more

A black spot on the sun will probably give Alaskans some great auroras for about five days beginning March 21, according the Charles Deehr, one of the Geophysical Institute scientists who forecasts auroras. The dark splotch on the x-ray image of the sun is known as a coronal hole, an area of the sun devoid of solar flares, sunspots, and anything else scientists can identify from our perch millions of miles away.

“I can’t say how far south the aurora is going to be, but it’s going to be active,” Deehr said of the period from March 21 to March 26, 2000.

Until Skylab astronauts photographed the sun with an x-ray camera in 1974, scientists knew little about coronal holes, according to Syun-Ichi Akasofu, director of the International Arctic Research Center. In 1905, British astronomer E.W. Maunder noticed that magnetic disturbances on Earth sometimes occurred about every 27 days. He also knew that the sun spins in a complete rotation every 27 days, so he thought that… read more

Like millions of tiny paratroopers, snowflakes fall through the Fairbanks sky, touching down on a blanket already 15 inches thick. Now seems a good time to ponder the cold, white substance that covers Alaska most of the year.

Snow forms high in the atmosphere with the help of particles, such as dust, volcanic ash or sea salt. These flecks serve as condensation nuclei-something onto which water vapor can cling. Without these little particles, water vapor can remain unfrozen down to minus 40 degrees. The meeting between a supercooled cloud of water vapor and a sprinkling of dust often results in a snowstorm. Seeded with dust, supercooled water vapor turns into ice crystals.

These ice crystals then latch onto surrounding molecules of water vapor as they float around within the cloud. As the crystals grow, parts break off and act as nuclei for other crystals. As the crystals fall through warmer layers of air, they link up by the thousands to form snowflakes.… read more

People in Anchorage and south will receive a gift from the sun in the year 2000. In what scientists call the "solar maximum," a time of increased activity on the sun, auroras should dip below the Arctic more often.

During the solar maximum, the nuclear furnace within the sun spouts more flares and develops dark splotches known as sunspots. For reasons unknown, sunspots and solar flares peak about every 11 years, and now is the time. The solar maximum will allow people as far south as Seattle to see the aurora from one to five times a year, said Charles Deehr, the auroral forecaster at the Geophysical Institute. The event probably won't affect aurora viewing in Fairbanks and points north.

The aurora will be visible from points closer to Earth's equator because the electrical circuit from sun to Earth sets up well during a solar maximum. As a solar flare explodes on the surface of the sun, it creates a shock wave in the solar wind that helps peel away the magnetic… read more

Climate change caused by people is a tough thing to measure in most places, but not in big cities. The clustering of humans, cars, pavement and rooftops makes some cities warmer than surrounding areas. Called "urban heat islands," they exist from Los Angeles to Atlanta to New York. Even Alaska has one.

A few researchers in Berkeley, California have devoted themselves to the study of heat islands. They've found that Los Angeles is 6 to 8 degrees Fahrenheit warmer than the surrounding areas. That may not seem like a lot, but those few degrees add up when you multiply them by the cost of air conditioning in millions of homes and offices.

The Heat Island Group, as the researchers call themselves, reports that intense heat absorbed by dark shingles can penetrate buildings, making air conditioners work harder. Members of the research group compared roof surfaces by painting one roof black and another white. The black roof was 70 degrees warmer than the air. The white… read more

Lightning, long thought to have a fondness for high ground, may instead have a thing for the boreal forest. At least that's what University of Alaska researchers who track lightning strikes are finding.

Because lightning is responsible for most of the acreage burned in Alaska every year, Bureau of Land Management technicians installed lightning sensors at Unalakleet, Bethel, Galena, McGrath, Tanana, Bettles, Ft. Yukon, Fairbanks and Tanacross. Most of the sensors are in the Interior because that's where the vast majority of lightning strikes happen.

Dorte Dissing and her academic advisor Dave Verbyla, both of the UAF department of forest sciences, use BLM sensors to track lightning strikes. While working on her Ph.D. degree, Dissing and Verbyla noticed that dots on a map representing lightning strikes neatly covered the range of boreal forest in Alaska. Boreal forest consists of spruce, birch, aspen, willow and other trees. The area in Alaska covered by boreal… read more

Creeping glaciers, ash-spouting volcanoes and persistent earthquakes that rearrange the landscape make Alaska an exciting place to live. A less dramatic feature of Alaska's landscape, permafrost, is also changing Alaska as it slowly disappears.

Permafrost, ground that remains frozen all year, forms a foundation for about 85 percent of Alaska. From Barrow to Anchorage, most of the ground beneath our feet contains frozen soil and ice that sits in spaces between soil grains or takes the shape of wedges, lenses and veins.

North of the Brooks Range, permafrost is generally found everywhere you might sink a drill. Farther south, permafrost is spotty but still plentiful. Alaskans have adapted to the challenge of building on permafrost with clever engineering tricks, but a warmer climate might soon make all our adaptations pointless.

Tom Osterkamp and Vladimir Romanovsky think permafrost might soon be on the minds of all Alaskans, and not just when they drive… read more

The recent discovery of three planets orbiting a sun-like star once again raises one of mankind's favorite questions: can life exist on other planets?

Someday, the aurora might help find an answer, according to Syun-Ichi Akasofu, director of both the Geophysical Institute and the International Arctic Research Center at the University of Alaska Fairbanks. Akasofu has studied the aurora since 1957, and he thinks other planets' auroras could be used to detect life elsewhere in the universe.

The idea was inspired by the discovery of three planets circling a sun that's much like ours, though a bit bigger. The star, Upsilon Andromedea, is 44 light years away, which means a spacecraft moving at the speed of light would take 44 years to get there. Still, it's not too far away by astronomical standards (the diameter of the Milky Way is about 100,000 light years).

The most significant part of the discovery is that it shows our solar system is not unique: maybe… read more

It's getting ridiculous. Alaska already has the highest mountain in North America, more miles of coastline than all the lower 48, and thousands of glaciers and grizzlies. Now comes the claim that a spot in Alaska is the wettest place on Earth.

First, a nod to the reigning champ (sorry). Mount Waialeale, on the island of Kauai in Hawaii, rises 5,000 feet above the sea. As tropical trade winds heavy with moisture attempt to hurdle the mile-high bump, they leave more than 400 inches of rain each year on the mountain. If you saved all that water in a graduated cylinder, it would rise to 33 feet tall.

That's a lot of rain, but meteorologists have recorded even more impressive downpours. More than 1,000 inches of rain fell in Cherrapunji, India, during the monsoon season from 1860 to 1861. In March, 1952, 72 inches of rain fell in one day at Cilaos, on Reunion Island in the West Indian Ocean. Closer to home, on July 4, 1956, a cloudburst in Unionville, Maryland,… read more

I've never been there, but the Maldives sound like paradise. A chain of islands made of coral that grows on the tops of ancient, submerged volcanoes, the Maldives speckle the equator about 400 miles southwest of India. The islands are sandy, sunny, and covered with palm trees, but there's a problem in the air. Actually, the problem is the air, which is often hazy and polluted.

The brown air that sometimes hangs over the Maldives surprised scientists working on the Indian Ocean Experiment, a recent study to see how humans might affect climate by altering clouds. One of the cloud watchers in the Maldives was Glenn Shaw, a professor of physics at the Geophysical Institute, who traveled to the equator along with graduate students Will Cantrell and Barbara Trost. They were among 150 scientists who converged in an area that included the Arabian Sea, much of the Bay of Bengal, and the Indian Ocean surrounding the equator.

The scientists picked the remote area because… read more

For most of the year, Fairbanks, Alaska, defies meteorological logic. Unlike what happens in most places, Fairbanks temperatures often increase with altitude in the first few thousand feet above the ground. The blame goes to one of the most powerful temperature inversions on the planet, a phenomenon recently measured by Rick Thoman, lead forecaster for the National Weather Service Forecast Office in Fairbanks.

Thoman is a hill-dweller, living west of town in Lincoln Creek subdivision, about 1,600 feet above sea level. For the past two winters, he's compared temperatures at his home with those of a Weather Service observer who lives in the Goldstream Valley, about 590 feet above sea level and about 20 feet above Goldstream Creek. Thoman gathered his statistics in interior Alaska's season of strong temperature inversions, from October until about mid-March.

These inversions, in which warmer air forms a lid that sits above cold air, happen in part because Fairbanks… read more

Last fall, the prediction for Alaska's winter wasn't a warm one. La Nina, the cold-hearted sister of El Nino, was supposed to bring cold snaps and plenty of snow. Now that winter 98-99 in almost over, it's time to see what, if anything, La Nina has done to the north.

Ants Leetmaa is director of the National Weather Service's Climate Prediction Center in Washington D.C. He was in Fairbanks recently to spread the word about the climate prediction center, which issues season-long forecasts based on weather events that tend to be somewhat predictable, such as El Nino and La Nina.

La Nina, Spanish for "little girl," occurs when the waters of the Pacific Ocean at the equator are unusually cool. During the last La Nina in 1988, surface temperatures of the Pacific Ocean near the equator dropped as low as 68 degrees Fahrenheit from a normal temperature of about 80 degrees. Even though the cooling happens thousands of miles away, the interactions of ocean and atmosphere… read more

Waiting is the name of the game if you're in the business of launching rockets. No one knows that better than the staff at Poker Flat Research Range, located 30 miles north of Fairbanks. After scientists and technicians recently waited for days for the natural and manmade conditions that would allow a launch, three rockets roared northward from the range to begin the third decade of rocket launches from Poker Flat.

Kathe Rich is the operations controller at Poker Flat. Among her other duties, she's the voice behind launch countdowns. After a year in which there were no launches from Poker Flat, she was glad to share her space in the blockhouse, a concrete bunker covered with earth next to where the rockets wait to be launched.

"This is great," she said as people milled about the room at 4 a.m.. "This is what we're here for."

The researchers, rocket builders, and those who would launch the first rocket of the season were awaiting the 4:50 a.m. passage of… read more

During a major auroral display, intense electrical currents exist in the ionosphere over Western Canada and Alaska. Flowing mostly eastwest at altitudes near 100 km (60 miles), the currents can be as large as a half million amperes.

Called the auroral electrojets, because the currents flow in relatively confined regions in and near the aurora, the currents nevertheless are diffuse, compared to currents in wires. At times, the electrojets spread over a zone several hundred miles wide.

So far, no one has any concept of how the auroral currents could be harnessed for useful purpose. In fact, as far as the works of man are concerned, the intense currents are more harmful than helpful.

Though the auroral electrojets are high above our heads, they do induce similar currents in the conducting earth beneath our feet, and in other conductors such as electrical transmission lines and metal pipelines. Like the aurora, the auroral eletrojets change rapidly with… read more

I was eating a cheeseburger at a restaurant in Healy, Alaska, last weekend when a man pounded on the window. He pointed to something he needed to share with a stranger--a purple river of aurora flowing directly over his head.

Soon, the entire restaurant staff and I were shivering outside, looking up at bands of aurora borealis that rippled from east to west. Even the sourdoughs who had seen hundreds of displays started whooping as the show went on. This was no ordinary aurora. People saw it clearly through the light pollution of downtown Anchorage. Those in Juneau saw displays more typically seen in Fairbanks. Bands of aurora flickered over Seattle and upstate New York.

Many scientists compare the aurora to an electrical generator that sputters at times, purrs at others. That night, the generator ran beautifully, said Charles Deehr, the Geophysical Institute's aurora forecaster and a professor emeritus. Deehr's job includes listing weekly predictions of aurora… read more

A few months ago, I wrote a column about climate change that involved James Hansen, a researcher at the NASA Goddard Institute for Space Studies in New York. Hansen and his colleagues developed a "common-sense climate index" to locate areas on the globe where climate change is noticeable enough to be obvious to people who aren't scientists. Hansen's index suggests that long-time residents of Alaska and Siberia already may be noticing a significant change in weather over the past few decades. I asked Alaska sourdoughs for some of their thoughts. Here's what I got:

Herman Hoke has lived in southcentral Alaska for more than 40 years. He wrote a four-page letter filled with detailed observations: "Is it really warmer now? Definitely yes. My truck tires haven't squeaked on the snow, nor have they galloped down the road for several miles on frozen flat spots because of low temperatures."

Jude Henzler, executive director of the Bering Sea Fishermen's Association, came… read more

In dozens of studies, including some done here at the Geophysical Institute, scientists have concluded that the planet is getting warmer, and the species performing the studies carries much of the blame. But why believe in global warming if we can't feel it?

Longtime residents of Alaska and Siberia may already be able to feel global warming, according to James Hansen, a researcher at the NASA Goddard Institute for Space Studies in New York. Hansen and his colleagues have developed a "common-sense climate index," to locate areas on the globe where climate change is large enough to be obvious to mailmen, secretaries, and other people who don't study global change for a living.

Using global weather records, Hansen based the index on conditions familiar to non-scientists--the number of hot days and the number of days with intense rainfall. Scientists believe a warmer planet will feature more hot days and more wet days. Dry areas will get hotter, and warmer… read more

Like most creatures, salmon are a tough lot to predict. Some years, so many salmon return to a hatchery that fisheries managers give them away in parking lots. Other years, fishing boats are halted at the docks because biologists find too few fish in the ocean to support an opening.

Though predicting salmon runs is harder than predicting the weather, researchers have noticed a trend: when Alaska wins, the Pacific Northwest loses. Some biologists and oceanographers think they might know why.

Flipping through old issues of fishing journals, Steven Hare of the International Pacific Halibut Commission was struck by the correlations he saw between Alaska and Pacific Northwest fisheries. In 1915, a reporter in Pacific Fisherman wrote that Bristol Bay salmon packers returned to port early due to a lack of fish. At the same time, the chinook salmon run up the Columbia River that borders Oregon and Washington was the best in 25 years. In 1939, the Bristol Bay salmon run… read more

Sometimes studying the aurora is like hunting moose. You know your quarry is out there, but you don't know its size, or exactly when or where it will appear. You can wait for your target to bump into you, or you can stalk. Several Geophysical Institute scientists chose the latter approach recently, and it worked; if they were moose hunters they would be wrapping steaks right about now.

In their pursuit, the aurora researchers took off in a small jet from Fairbanks every night for two weeks. They did their work around new moon, when the moon's position between Earth and the sun didn't allow a bright moon to interfere with their aurora chasing. On a typical night, Hans Neilsen, the project leader and a professor of physics at the Geophysical Institute, and Daniel Osborne, the project engineer, would locate the aurora on TV monitors within the jet. The TV screens beamed images from three cameras mounted on top of the jet: two narrow-field cameras and an all-sky camera,… read more

Between El Nino and conferences on global warming, weather, climate, and the disagreements among scientists about weather and climate have been filling the news lately. Given the complexity of this dynamic planet, it would be astounding if researchers didn't disagree. To me, the really amazing thing is that scientists are doing so well at making increasingly precise measurements and then building them into ever more accurate projections. The improving precision is well illustrated by the significantly larger quantity recently assigned to the amount by which the full moon heats the polar atmosphere.

Almost sneaked that one past you, didn't I? Yes, the moon apparently does affect temperature at high latitude--though not so much that you should run out and moonbathe in the buff this weekend. Near the time of the full moon, the polar air is warmed by a bit more than half a degree centigrade over its temperature at the time of the new moon. That may not sound like much, but… read more

When Jennifer Kimball looked up at the night sky last winter, she noticed something special--a solid green curtain of aurora borealis that seemed to be cleaved in two by a long line of black arcs.

On that February night, Kimball, a graduate student studying space physics at the Geophysical Institute, caught her first live glance of her thesis topic--the black aurora. She later confirmed she wasn't imagining things by watching a video of that night's aurora activity taken at Poker Flat Research Range north of Fairbanks.

Black aurora isn't actually aurora at all; it's the lack of aurora activity where it seems like the aurora should be. Kimball and her advisor, Geophysical Institute Professor Emeritis Tom Hallinan, showed me a black aurora that was captured by a narrow-field camera at the former Ester Dome observatory in Fairbanks in the 1970s. Kimball hit the play button and pointed out three major types of black aurora: black curls, which corkscrew across a… read more

Fairbanks--As I was moving slowly northward two days ago, I stopped at the North Pole McDonald's to offset the deficiencies of my hiking diet. In between bites, I read an Alaska newspaper editorial crediting El Nino for the nice weather that has allowed Jane and me to sleep without a rainfly for all but a few nights on our walk across Alaska.

Is El Nino, a warm ocean current, responsible for much of Alaska's recent hot, dry and sometimes windy weather? "No," said Ron Stuvek, an assistant forecaster with the National Weather Service in Fairbanks. "It's a consistent high-pressure system." According to Stuvek, much of the state has been effected by a high-pressure system since early May.

"It's not an isolated high-pressure system," Stuvek said. "It's statewide, from Bristol Bay to Kotzebue. Yesterday, Annette and Ketchikan (both in Southeast Alaska) got two-tenths of an inch of rain; everywhere else there was nothing to speak about."

At that point in the… read more

I admit it: I'm a thermometer junkie.

I have three of them attached to my home, and I've memorized three phone numbers of recorded voices that tell me the temperature at three other places. I know I have a problem, but the busy signals I hear during a cold snap tell me I'm not alone.

Since I don't seem to be the only one afflicted with mercury madness, I'll indulge in temperature trivia lifted from my favorite non-human sources: the textbook Meteorology Today and It's Raining Frogs and Fishes by Jerry Dennis.

First, a look at what our thermometers are measuring. Because hot and cold are relative terms, sometimes our senses can't be trusted to tell us the difference. For example, a tub of ice water will feel warm if you stick your foot in it after walking barefoot at 40 below.

Real hot and cold can be thought of as a measurement of motion: the temperature of water, air, motor oil or any other substance is a measure of the average… read more

A hitchhiker I toted on the Dalton Highway recently told me he'd seen a "dust devil" dance down the road like a mini tornado. I felt deprived because I'd never seen one. As if by design, one appeared in front of me the next day.

While driving down a dry gravel road, I saw dust rotating on the ground like a dog chasing its tail. The funnel of twisting air grew until it rocked the tips of nearby spruce trees. Then it ran to the surface of a nearby river, where it touched down with the sound of a plastic tarp shredding in the wind.

Dust devils, also called whirlwinds and willy-nillys (in Australia), happen frequently in the desert and occasionally on Alaska roads, parking lots, and other hot surfaces.

Dust devils are born when sun-warmed air over a road or parking lot rises rapidly through layers of cooler air above, said Dave Hefner, a meteorologist with the National Weather Service in Fairbanks. As a blob of warm air quickly rises, it's turned in a… read more

Science Forum reader Rod Boyce wants to know why his cabin sometimes turns into highway-front property, or at least sounds like it, when it's cold outside. He lives about a mile from a major road, but he notices that the sound of passing cars and trucks seems to be amplified during the winter. I checked, and he doesn't have a faulty hearing aid.

Many people living in Fairbanks have noticed the same phenomenon. My cabin, for example, is 10 miles from Fairbanks International Airport, yet during the winter it often sounds as if I live on the runway.

According to Geophysical institute Professor Emeritus Juan Roederer, unusually loud jets, trucks, and trains in cold weather are signs of a strong temperature inversion over the city.

Temperature inversions--which occur when warm air sits above cold air--form frequently in Fairbanks because of three environmental quirks: a lack of sunlight that fails to warm the earth; clear skies that allow heat to radiate… read more

For many Alaskans, January 1989 is a month that still numbs the mind because of the cold snap that gripped much of the state for two weeks. In Fairbanks, fan belts snapped like pretzels; ice fog was so thick that one was indeed tempted to slice it; and the city came as close as it ever comes to a halt, with many people opting to stay home after their vehicles succumbed to the monster cold.

The 14 days of bitter cold were not a strictly Fairbanks phenomenon. Everywhere but the Aleutians and Southeast was nailed by a combination of meteorological quirks that resulted in what some called "a good old-fashioned winter."

The cold air that besieged the state was born over the Beaufort Sea and stuck in Alaska as a huge high-pressure ridge from Siberia expanded across the state, according to John Lingaas and Rick Thoman, meteorologists with the National Weather Service in Fairbanks.

Frigid air within the high-pressure system sat over the state like a sumo… read more

Late-night glimpses of the aurora borealis took on a new meaning for me last fall after Genezaret Barron was killed. Barron, a gentle soul, was a Fairbanks freelance photographer who captured the aurora on many a frozen night. Before he was murdered, I'd often think of him during auroral displays. I knew that while I was heading back indoors to hug the wood stove, Barron would be out on some dark hilltop, pointing a camera skyward.

Now I think of him in a different way when a particularly active display of the northern lights forces me to stare upward. Thumbing through a few books on aurora legends, I found some cultures associated the northern lights with spirits of those who passed on.

Before scientists discovered that the northern lights were caused by charged particles from the sun colliding with gases in the earth's atmosphere, people were left to their imaginations to explain the dancing lights in the sky.

The Eskimos of Labrador, Canada, believed… read more

Not only is Alaska the best spot in America to hook a king salmon, see the Northern Lights, catch a midnight sun tan and study mosquitoes, the state also happens to be one of the most fertile breeding grounds for rainbows.

Spotty summertime afternoon and evening rains in Alaska make for perfect rainbow conditions when coupled with the fact that our position on the earth causes the sun to hover just above the horizon for a long time here. Rainbows are tallest and most vivid when the sun is at a low angle, as is so often the case in Alaska.

Rainbows form when the sun is shining in one part of the sky, it's raining in another, and the rainbow-seer is somewhere in between, with his or her back to the sun. According to Jerry Dennis, in his book It's Raining Frogs and Fishes, individual rain drops act together to separate the light of the sun into the reds, yellows, oranges, greens, blues and violets we see as the colors of a rainbow.

The show begins… read more

As I watched a movie with friends recently, three dogs in the room suddenly began to act out their roles as house guardians by running to the windows and barking at a distant rumbling. We humans were puzzled until flashes in the cloudy night sky soon identified the intruder, and we walked out on the deck to enjoy a rare May thunderstorm.

As often happens when natural phenomena occur, questions were thrown at the nearest science writer: "what causes lightning and thunder?" and, "doesn't lightning strike from the ground up?"

Scrambling for the textbook Meteorology Today, I relearned that lightning is an electrical discharge identical in everything but size to the spark that jumps from your hand to doorknob in a carpeted room.

The lightning that most impresses us---that which strikes the ground---represents only about 20 percent of the lightning generated within a cloud. Most lightning strikes occur within a single cloud, while others reach from one… read more

Northern scientists who study climate change today often use innovative techniques to determine an area's temperature centuries ago. Pictures of ancient weather often are painted by those analyzing polar ice cores, sea floor sediments and permafrost. But few researchers have been as ingenious as those at the University of Michigan; they're literally pulling teeth--ancient Viking teeth--to come up with a new way to figure out old weather patterns.

Spurred on by the knowledge that tooth enamel contains information that can be directly correlated to drinking water, University of Michigan geochemist James O'Neil and graduate student Henry Fricke recently used 29 teeth found in remains at ancient Norse colonies to confirm a local temperature decrease at the onset of the medieval Little Ice Age, hundreds of years ago.

University of Copenhagen anthropologists gave O'Neil and Fricke the teeth, which originally belonged to Vikings and Inuit Eskimos who lived at three… read more

If you've lived for any length of time in the northland, and if you read articles like this, then you probably know what causes the northern lights. Properly known as the Aurora Borealis, these spectacular bands and curtains of light in the night sky can be seen more frequently in Alaska than in any other state of the union, and they shine above the Interior more often than anywhere else. (Statistically, Fort Yukon is the aurora capital of the world.) So we sometimes claim them as our own, and cheechakos and Outsiders rightly expect us to be experts on this phenomenon; the ability to explain auroras is a matter of pride as well as fulfilled curiosity.

It's understood that the sun ultimately causes the aurora. The picture as we understand it was explained in this column by geophysicist Dan Swift 17 years ago. "It is almost certain," he wrote, "that the energy to power the aurora comes from the sun. From the sun there is a continuous outflow of matter in the form of… read more

The boss has been uncommonly busy lately. Directing the Geophysical Institute is enough to keep anyone hopping, but Director Akasofu also is preparing for an international scientific meeting for which he will play host. It's only fair; the field considered and celebrated at this gathering, the Second International Conference on Substorms, is one Syun-ichi Akasofu virtually invented.

Or, more properly, the subject is a phenomenon that he helped discover and establish. When Akasofu came to Alaska in the late 1950s, it was to study under the guidance of Sydney Chapman, a distinguished British scientist who served as scientific director of the institute for 21 years. This was a logical place for the student from Japan to find a mentor from England, for then as now, interior Alaska was the best place in the world to observe auroras, and both Chapman and Akasofu wanted to understand these mysterious northern lights.

Then as now, professors can assign time-consuming… read more

I got word recently that a new building on the Poker Flat Research Range is being christened for Neil Davis, who served as first director for the range and who---sometimes by using imaginative and unorthodox methods---was chiefly responsible for creating the facility. I helped with public information during those early days, and grew to appreciate Davis' skill at explaining things clearly (that is, when he had time to explain things at all).

It's harder for me to catch the now retired Professor Emeritus Davis these days to ask for explanations, but fortunately he's taken up writing books to keep himself busy. The books have an adequacy of explanations, and sometimes even describe problems in need of explanation. For example, in The Aurora Watcher's Handbook, Davis devotes a short chapter to the connection between aurora and weather.

When you hear old-time Northerners comment, "Great weather for the aurora tonight," they are actually reporting on viewing… read more

A distant flicker and grumble to the northeast told me the weathermen had it right. Scattered thunderstorms had formed over the Tanana Uplands, and the sultry afternoon sky was getting pretty lively. Now, if I could only remember the trick for telling how far away the storm was...

The Weather Book is my favorite quick source on weather-related matters. Author Jack Williams has studied meteorology, but it's his journalism work with the weather page for "USA Today" that led to the book. According to Williams, we see the lightning's flash the instant it strikes---which is reasonable, since it travels at the speed of light. By comparison, sound dawdles on its way to us. It takes about five seconds for the thunderous sound of a lightning strike to reach a mile away.

Properly, the form of rowdy weather that produces this sound and fury should be called a lightning storm rather than a thunderstorm because lightning is what causes thunder. Apparently the real… read more

"I saw a terrific auroral display the other morning," my friend said. "You know, one of those that make you think your eyes aren't working right? Off and on, sort of like strobe lights.

I knew exactly what he meant, even though I hadn't seen that particular northern lights show. He'd seen a good display of pulsating aurora.

Not many casual sky watchers are fortunate enough to observe a pulsating aurora. Even though this auroral form is not really uncommon, there are several good reasons for its status as a rarely seen phenomenon. For one thing, it isn't as eye-catching as discrete aurora, the arcs and bands we think of when someone mentions the northern lights. Observed without the help of instruments, pulsating aurora seldom shows the intense colors or captivating, curtain-like shapes of more familiar auroras. In fact, it is generally less intense in all ways; its light is dimmer and its form is patchier. Usually it comes and goes so quickly that the eye can'… read more

"Nice column you did about the new aurora videotape," said an acquaintance. "Only thing is, you left out the science." Doggone! Knew I'd forgotten something...

The column I wrote a while back (which may or may not have appeared in your newspaper) ended up being on "The Aurora Explained" tape prepared by scientists at the Geophysical Institute, but I'd intended to write about something mentioned on the tape. Research Associate Gina Price tells what causes the colors appearing in the northern lights. (See, Christmas was coming, and I thought something about colored lights would be seasonally appropriate...Never mind. I meant well.)

With more detail taken from The Aurora Watcher's Handbook here's the basic explanation. First, envision a neon sign. Plug it into a source of electric current, and the sign lights up. That happens because, as the electrons of the flowing current hit the molecules of the neon gas, the neon emits light.… read more

Cleverly, just in time for Christmas, the Aurora Color Television Project here at the Geophysical Institute has released a new videotape explaining---and showing---the northern lights. I had a chance to preview the not-quite-done tape a few weeks ago, and thought it was delightful.

Hey, it's always fun watching friends perform on TV. There on the screen were people I knew well, explaining aspects of the aurora in clear, simple terms; there I sat, watching the electronically packaged explanations roll by, even though two of the experts on the tape---Tom Hallinan and Dan Osborne---have offices right off the same laboratory where I watched. I could have wandered into their offices and asked questions of the real people.

But this once, taking what I was given was more fun than asking. For one thing, the on-tape explanations are good ones, and they come with really impressive illustrations. The tape, called The… read more

This summer's bluegrass music festival in Talkeetna, I'm told, was interrupted by a spectacular early-season auroral display. The festival management respectfully turned off the stage lights so all could watch the shimmering sky undistracted.

Perhaps they should have turned off the music, too. With all those attentive listeners and bits of sensitive equipment on hand, folks at the Talkeetna festival might have bagged the first authenticated record of auroral sound.

Many records of auroral sound exist, but none are the sort one can play back. A scan of the appropriate chapter in The Aurora Watcher's Handbook reveals that author Neil Davis has tallied about 300 documented anecdotal reports of people hearing the aurora. (In scientific circles, "anecdotal" covers everything from hearsay to personal eyewitness---or earwitness---accounts by trained observers. Anecdotal evidence counts, but not for much.)

The anecdotes sketch a peculiar picture. In a… read more

As interior Alaska basked in a splendid September, people praised the skies: "Thank heaven for the greenhouse effect---this weather is wonderful!" Sometimes these rejoicings came from the same people who swore last winter was the worst they'd ever seen.

Meanwhile, residents of Anchorage were deciding whether to settle for gumboots or put on swim fins just to get to the car. They could note that if Alaska was supposed to get drier as the greenhouse effect takes hold, somebody must have left the greenhouse door open. Some of these people had earlier complained about having to water gardens suffering in a hot dry spell.

So Alaskans may well ask: Just what is going on here? Is there a greenhouse effect? Is it doing anything? To which scientists could answer, in order: Nobody yet knows; of course; and Probably, but it's too soon to tell.

That, at least, is how I translate a recent review article in the journal Nature. Author John E. Walsh, who is in… read more

As soon as the August rains let up, people living in interior Alaska could see the aurora (or northern lights) again---at least the nighthawks could. The best shows come late, it seems.

Aurora occurs all year, as the faithful electronic measuring devices here at the Geophysical Institute inform us (though institute director Syun-ichi Akasofu has told me they are least common near the solstices, for reasons no one yet properly understands). Images captured by high-flying satellites prove that the instruments are honest. Summer aurora is invisible to us because the long daylight keeps the sky too bright for the dancing curtains to be seen.

In fact, part of the reason that aurora displays in late August and September seem to occur only late at night is that twilight still lingers. It takes a few hours for the sky to darken sufficiently for the aurora to show up. Later in the year, the dancing lights may appear early enough to distract people driving home after work… read more

When I asked a weather expert if Alaska has tornadoes, I got a quick answer: No tornado has been officially recorded here. Unofficially, tornadoes---or at least funnel clouds---are reported most years. Because Alaska has few trained observers but many pilots, boaters, campers, and other wanderers watching the state's skies every summer, casual observations are easier to come by than official ones.

Yet it isn't only that Alaska's wide open spaces make tornadoes seem rare here. They are rare. Our weather and terrain, like those in the neighboring chunks of Canada, just don't make for ideal tornado habitat.

That's something for which we can be truly glad. A tornado can do an astounding amount of damage. The June 1991 issue of Weatherwise magazine contains an article by C. Hugh Snyder, a retired National Weather Service meteorologist, that offers clear explanations of the behavior of these peculiar and dangerous storms as well as some examples of their… read more

We talk about summers being warm or cool, wet or dry. In practice, this is generally in comparison to what we perceive as normal for our particular locality. Precisely defining a "normal" summer, however, is a bit more complex: the one thing we can be sure of is that any particular summer will not be exactly normal.

In practice, a "normal" summer would be one in which the temperature and precipitation for each day corresponded to the average values for that date over a number of years. It would be a dreary season, with a little rain every day, and no very hot or cold days. Such an imaginary summer, however, makes a useful ideal for comparing summers across Alaska, or for looking at how a particular summer differs from the norm at a given place. Here at the Geophysical Institute, we have charted these precipitation and temperature averages for a number of Alaskan stations.

You might think that the farther north you go, the colder the summer. This, however, is… read more

I don't know how it went for you, but by the fourth time I shovelled out the wretched car during the recent holiday season, I had just plain had it with snow. And, yes, science was slipping too: I had this vision of a wicked witch of the north with a gigantic vacuum cleaner. She was sitting atop Denali, pulling wet air out of the Gulf of Alaska and freezing it solid just inland of Nome, and all Alaskans were being buried under tons of white crud.

I've been able to shape a more accurate picture of what went on during December's closing days, thanks to Hiroshi Tanaka. He's an assistant professor of physics and climate expert here at the Geophysical Institute, and he gave me a short report explaining what's been going on with our weather.

He took December 21---our warm, wet winter solstice---as an example. Interior Alaska was indeed warm that day, with temperatures close to the freezing (or melting) point. That's 40°F above normal for the day. Nenana had rain; at… read more

If the headline had appeared in the National Enquirer or some such tabloid, no one would have thought it remarkable. But it turned up in the newspaper published by the Institute of Electrical and Electronics Engineers, and in a professional publication it did catch the eye: "Utilities engineers meet to discuss invisible threat from outer space."

What alarmed the engineers was not an invasion of bug-eyed monsters or little green men, but it did arrive unseen from a source beyond Earth, and it did cause big trouble. The same gigantic flare on the sun that brought Alaska a red aurora this past March brought problems to utilities engineers from California to Sweden. Transformers overheated, relays tripped spontaneously, capacitor banks misbehaved.

Those were the minor nuisances. In Canada, the solar flare led to a power outage for virtually the whole province of Quebec.

The villain in these problems is known as geomagnetically induced current, GIC… read more

"My fool travel agent," I overheard a tourist say the other day, "said Alaska doesn't have thunderstorms. I wish she was here to see and hear this." We were sheltered in a supermarket entryway near Fairbanks at the time, and indeed the downpour, rumbles, and flashes outside would pass as a thunderstorm anywhere in the world.

Yet the misguided travel agent was only partly wrong. In much of Alaska and neighboring parts of Canada, thunderstorms are exceedingly rare or virtually nonexistent. In other parts, as that tourist learned, a typical summer is well punctuated with thunder and lightning.

It's not the crossed fingers and longings of impatient fire-fighting teams that brings more thunderstorms to the Interior. It's a matter of relative temperatures at the earth's surface and in the sky above, and of the air's water content

Envision a good hot day in the Interior. There may be clouds overhead, but the sun is baking the ground surface. The ground heats… read more

Pollution usually brings to mind ugly things: smoke and smog, foul waters, litter, junk, crud are the understood symbols of a stressed Earth. Yet here in the high latitudes, we have a good view of what turn out to be some lovely warnings of pollution.

They're called noctilucent clouds. The name means that they shine at night, and it's apt. Noctilucent clouds gleam in late-summer evenings as if they're lit from within, but it's sunlight that makes them shine. They look brilliant in the evening sky because they are so high that everything lower is in shadow while they're still in sunshine. Noctilucent clouds lie 82 kilometers (51 miles) above the earth's surface; for ordinary clouds, that's too high.

A good thunderhead, at about seven miles up, is bumping into the realm of what we usually think of as the highest of clouds, the wispy cirus. Seven times higher, beyond the stratosphere and up into the mesosphere, conventional wisdom holds that there just isn't enough… read more

On the nights of March 12 and 13 this year, many Alaskans saw an extraordinary gift from the sun: a stunning display of the northern lights with great patches of red aurora.

Three days earlier on the sun, enormous flares had erupted. Thursday's flare, extending 70,000 miles into space, was one of the largest ever recorded. Eight minutes later, light from the flare reached observers on earth.

That radiation traveled at the speed of light, but the particles causing auroras move more slowly (about 400 kilometers a second, or 900,000 miles an hour). Instruments at the College Observatory on the University of Alaska Fairbanks campus recorded effects caused by arriving particles at 4:30 p.m. Sunday.

Auroras are produced by subatomic particles--electrons and protons--cast off by the sun. The particles stream outward into space as an enhanced flow called the solar wind. When the solar wind and the earth's magnetic field interact, electrical power is produced.… read more

For most people living in Alaska, January 1989 will be remembered as very cold. All four of our climatic zones felt the chill.

Homer is a typical location in the maritime zone of southern Alaska, where the weather is usually moderated by the ocean. This time Homer had five days of new record low temperatures, and its lowest low during the cold snap--24 degrees below zero Fahrenheit--was a new absolute minimum for that location.

For the intermediate zone between the sea and the interior, Anchorage weather is typical. During January's cold spell, Anchorage temperatures descended to -30oF, and two days set new record lows.

Interior Alaska, where Fairbanks is the biggest town, has continental weather. Continental weather is usually marked by temperature extremes, and the cold certainly felt extreme enough. Perhaps because extremes are more common here. Fairbanks reported only one day that even tied the… read more

From wind chill factors to air speed indicators, all the ways in which we refer to moving air have to do with how fast it is going. Yet that wasn't always true. The first international standard dealing with wind paid no attention to miles per hour, meters per second, or even knots. Thanks to geography, northerners have a special claim on that early standard.

Captain Francis Beaufort wasn't on the 1826 British expedition that identified the sea to the north of Alaska and western Canada given his name. He was in England, working as a hydrographer in the Admiralty. Reference books such as Orth's Dictionary of Alaska Place Names note that Sir John Franklin, who led the expedition, named the sea "in honor of his friend" Beaufort--but Franklin may have been motivated by political prudence as well. Beaufort was a rising star in the Admiralty, where he eventually became known to history as Admiral Sir Francis Beaufort, the man who invented the scale of wind velocities.

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People in Fairbanks enjoyed a relatively warm December again this year, with a record high of 40 degrees Fahrenheit on December 16. In effect, this heat wave arrived as the baggage of a meteorological tourist, a mass of subtropical air that unexpectedly blew into interior Alaska.

A wind from the south sounds warm by itself, but its heating effect on the Interior is enhanced by the Alaska Range. Air that flows from the south up over the mountain peaks dries out and is compressed as it sweeps down their north sides. When air is compressed, it heats up. That's why refrigerator coils are hot and why warm winds, or chinooks, are produced by the snow-capped Alaska Range.

On a grand scale or local one, warm winds in December are not what one associates with interior Alaska. How these winds originate requires some explanation of global weather patterns. Then we can ask what was unusual in those patterns during our comparatively torrid month.

Over… read more

Northerners love to brag about the horrors they must endure. We start with cold and snow, tell a few bear stories, go on through active volcanoes and earthquakes, and can always toss in the size of our forest fires. We imply that we have to be very tough people to deal with this tough land--until some city-bred Easterner smilingly asks us about the last hurricane to hit our local coasts.

Now, it's easy for us to come up with hurricane-force winds. Those are formally defined as winds moving at or faster than 120 kilometers an hour (73 mph, or 64 knots). In a typical winter, the Aleutian passes can easily muster that much wind--far too frequently for the comfort of those who fish offshore. For that matter, whenever there's a strong high-pressure zone on one side of our mountains and a low on the other, a great deal of air can howl in a hurry through the valleys. A homebuilder who wants a secure roof in Valdez, for example, should design it to withstand winds of 120 mph,… read more

If our great-grandchildren are still around a century from now, they will almost certainly be living in a world with different climates from what we know today. Carbon dioxide, methane, and more complex chemicals are building up in our atmosphere, and given the economic realities of life on an overcrowded planet, they will continue to build up at least into the 21st century. While there is plenty of room for doubt that the heat and drought of the summer now coming to an end were caused by these changes, it is almost certain that the changing chemistry of the atmosphere will produce clime changes of this magnitude or greater, probably within the next few decades.

The big unanswered question is what these changes will be. It is fairly simple to work out the direct changes in radiation and say that the coldest clear-night winter temperatures will be a little warmer next century, or that late spring and early fall radiation frosts will be slightly… read more

Crops aren't going to be very good this year in the midwestern United States and the Canadian prairie provinces. Here in Alaska, we'll probably see an increase in food prices; in other parts of the world dependent on American grain for food, there may well be starvation. Commentators have speculated that we may be seeing the first stages of the warming expected from the increase of carbon dioxide in the atmosphere. About that we can't be sure. What we do know is that the midwest drought is directly due to a large anticyclone --an area of high pressure and clockwise rotation -- stalled over central North America. But how does an anticyclone keep it from raining?

The problem is not lack of water vapor in the air. The absolute amount of water vapor in the air over the sun-baked midwest is probably greater than that over interior Alaska (where there's been more than enough rain this year). The problem is getting that water vapor to fall out as rain.

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On Christmas Eve, I was working outside my Fairbanks home in above-freezing temperatures. The following day, football fans nationwide watched the Sun Bowl game in El Paso played in a snow storm. This reversal of expected temperatures has been rather common in the last eleven years, and occurred at times (the 1962-63 winter, for instance) in earlier years. The culprit (or benefactor, from the Alaskan point of view) is something called the Pacific-North American circulation, or PNA for short.

The sun in fall and winter heats the Northern Hemisphere very unevenly. While the equator is still being warmed, air in the Arctic cools steadily, at a rate of around a degree or two a day. The rotation of the earth prevents this cooling air from mixing with the warmer air farther south, so a great dome of cold air builds up over the Arctic, bounded at its southern edge by a zone of rapid temperature change called the Arctic Front and by the great river of westerly winds aloft called… read more

The aurora does more than provide a light show on clear nights; it's the world's most powerful radio station as well. Most of the energy is beamed outward to the stars, but some of it can be listened to with a simple wire loop, about 10 meters across and in a vertical plane, attached through an amplifier to a pair of headphones. In the early morning hours you'll hear the chorus, or dawn chorus; in the evening, auroral hiss is more likely.

Dawn chorus is in the frequency range our ears respond to, about 400 to 1000 hertz, or cycles per second. It's made up of radio waves rather than sound waves, which is why you need the wire loop and headphones to hear it. These waves come in a series of short, rising tones, like a tree full of birds on a spring morning.

Chorus is actually generated by fast-moving electrons which are trapped by the geomagnetic field over the equator, near the orbits of the geostationary satellites that transmit our telephone calls and bring us live… read more

Is it really getting warmer in Alaska?

Certainly the year just past, like the ten before it, was warm. It's also had some precipitation extremes -- wet on the south coast, with some months having up to three times their normal precipitation at Yakutat, but rather dry in the Interior, where Fairbanks, for instance, had its second driest year on record. Southeastern was also warm, with Juneau having above-freezing average temperatures in every month, and January, February, November, and December all more than five degrees above normal. Even Anchorage, where June and July were admittedly cool and cloudy, finished the year almost three degrees above normal. The lack of really cold weather was also noticeable -- both Barrow and Fairbanks temperatures just brushed minus forty in January, while Barrow had three days of 40 below averages in February. Neither station had so much as a forty below minimum temperature during the rest of 1987.

Both… read more

When this article was originally released, it was accompanied by a different local weather chart for each location to which it was sent. Today similar charts are available for a number of Alaskan locations on the Internet.

Five months ago, this column was devoted to a summary of the average climates around Alaska during the "warm" season -- April through September. We're now well into the cold season, and it's time to look at the weather around the state in the interesting part of the year. The variability from place to place and even from day to day is extreme.

The Interior once again has the most spectacular record, with differences between record high and record low temperatures in December and January being as much as a hundred and ten degrees F -- from 50 above to 60 or even… read more

We talk about summers being warm or cool, wet or dry. In practice, this is generally in comparison to what we perceive as normal for our particular locality. Precisely defining a "normal" summer, however, is a bit more complex: the one thing we can be sure of is that any particular summer will not be exactly normal.

In practice, a "normal" summer would be one in which the temperature and precipitation for each day corresponded to the average values for that date over a number of years. It would be a dreary season, with a little rain every day, and no very hot or cold days. Such an imaginary summer, however, makes a useful ideal for comparing summers across Alaska, or for looking at how a particular summer differs from the normal a given place. Here at the Geophysical Institute, we have charted these precipitation and temperature averages for a number of Alaskan stations.

You might think that the farther north you go, the colder the summer. This, however, is only… read more

Although winter clouds over most of Alaska are usually found in rather dreary sheets, in summer the puffy cumulus clouds punctuate the sky. These clouds may vary from snowy wisps of cotton candy to towering hard-edged thunderheads, and indeed may change from one extreme to the other in a startlingly short time. On other days, they may remain like flattened heaps of whipped cream, or march in ordered rows away from areas of high ground.

Cumulus clouds owe their existence to the heating of the earth's surface by the sun. The heated ground heats the air it touches; that warmed air then rises through the cooler air higher up in the atmosphere. If a particular area is warmer than another area close by, the rising air will be concentrated over the warmer area.

Air, like everything else, has to do work to go upwards. The energy for this work comes from the heat energy of the air, so the air cools as it rises. Warm air can hold more water as vapor (… read more

Although a few cases remain unexplained, the overwhelming majority of "Unidentified Flying Objects" (UFO's) are in fact identified rather quickly. Weather balloons, high altitude research balloons, the planets Venus and Mercury, and certain clouds have all produced UFO reports. (My own "UFO" turned out to be the reflection of a street light on a telephone wire.) The clouds most likely to produce flying saucer reports are lenticular clouds, which are common in Alaska in the winter.

Lenticular clouds, also known as wave clouds, are the most common member of an unusual class of clouds that remain stationary while the wind blows through them. They are normally generated by mountains, and almost every place in Alaska has enough mountains to allow wave clouds to be observed. They form because of two fundamental properties of air and water. First, when air is lifted and expanded, it cools. This is why temperature normally decreases with height. Second, as air… read more

Anyone who hasn't spent the last few years in the Bush without a radio has probably heard of the greenhouse effect by now. Carbon dioxide is an important "greenhouse" gas: it allows sunlight in to heat the surface of the earth, but blocks thermal radiation from leaving. Mathematical models indicate that an increase of carbon dioxide in the atmosphere should increase the average temperature of the earth. Carbon dioxide is indeed increasing, from about 270 parts per million (ppm) before the industrial revolution and 300 ppm in 1900 to 345 ppm in 1985. The buildup is thought to be due largely to the burning of fossil fuels, but with an additional component due to the destruction of forests, especially tropical rain forests. None of the models, however, are complete, especially with regard to possible effects of clouds. And in spite of the measured increase in carbon dioxide, global temperatures don't seem to have risen much, if at all. Will carbon dioxide really cause a warming?… read more

Envision this: midwinter on the Bering Sea. The temperature is 40 below. The ocean is sealed beneath a lid of ice--almost. At a handful of places, the Bering Sea has peculiar patches of open water. These watery holes are called "polynyas."

Although at first glance that might look like another word to describe a Goody Twoshoes, it is actually a Russian word that means "open places in the ice." Scientists who study ocean ice use it to refer to irregularly shaped openings with sides that could not be refitted to form a uniform sheet of ice (to distinguish them from fracture openings such as "leads"--cracks that fortuitously open or close in tales of Arctic adventure). In other words, they do not create chunks that you could fit back together like the pieces of a jigsaw puzzle.

In the Bering Sea, polynyas tend to occur winter after winter in just about the same places. The most persistent of these appear south of Point Hope, the Seward Peninsula and, most… read more

It has long been known that auroral activity undergoes a systematic change of forms during the course of a night. Until the early 1960s, most auroral scientists believed that there was a fixed pattern of auroral forms under which the earth and an observer on it rotated once a day. The fixed pattern consisted of quiet curtain-like forms in the evening sky, curtains with folds and waves around midnight, and isolated rays and patches in the morning sky.

Beginning in 1961, S.I. Akasofu, a young researcher at the Geophysical Institute (and now holder of the Sydney Chapman chair at UAF), began the study of a large number of auroral photographs taken simultaneously at widely scattered locations in Siberia, Alaska and Canada. Some of the things that he noticed led him to question the concept of a nightly fixed pattern of auroral forms.

What Akasofu discovered was that during a quiet period, the aurora can have a simple curtain-like form over the entire dark hemisphere… read more

Before the last holiday season, there was considerable advance publicity about an artificial "Christmas comet" which was to be produced by the injection of barium crystals into space from a satellite in high earth orbit. Alas, even though the experiment was a success and faintly glimpsed by some observers to the south, it was never seen in Alaska.

However, since the mid-1970s, similar experiments have become old hat to Geophysical Institute researchers and other scientists from around the world who have been launching barium payloads into the aurora from the Institute's rocket range at Poker Flat north of Fairbanks. The primary difference between the Christmas comet experiment and those performed at Poker Flat is that the former was intended to observe the solar wind, while the latter, where the observations are made closer to earth, provide information relating primarily to the earth's magnetic and electric fields.

Typically, a barium-release experiment at Poker Flat… read more

As Professor Syun Akasofu of the Geophysical Institute points out in his book Aurora Borealis, the Amazing Northern Lights, the subject of whether the aurora produces sounds can easily become a springboard for losing friendships. There are a few old-timers who insist that they have heard it, but many more long-time residents of the northland insist that this is hogwash.

As reported, the sounds usually resemble a swishing or crackling similar to that heard as waves of static on the radio. The level of intensity is said to change along with the rapidity of movement of the auroral forms overhead.

Most scientists tend to view claims of auroral sounds with skepticism for at least two good reasons. One is that, even though serious attempts at recording them have been made, none have been successful. Another is that a valid physical reason for their existence is difficult to find. Because there is insufficient air between the aurora and the ground to transmit… read more

 

In Fairbanks, normal winter low temperatures are about -20°F, and in Anchorage they are about +5°F. The lowest recorded temperatures at both places are, of course, considerably lower than that, reaching -66°F at Fairbanks and -38° at Anchorage.

To Alaskans, cold, ice and snow are nothing new. Sometimes it is difficult to imagine that there are even colder places elsewhere on earth, but there are. Alaska really has quite a mild and balmy winter climate compared with some other

One would intuitively think the two poles two should be the lower temperatures places, that the closer one gets to them the lower it gets, but this is not so. In the north polar regions, the coldest place is not at the North Pole but near Verkhoyansk in Siberia where the lowest recorded temperature is -94°F. Extreme cold is experienced here because Verkhoyansk lies in the middle of a large land mass which can cool in winter much more than the Arctic Ocean where the North Pole is located… read more

I had an interesting chat over the phone the other day with Ted Fathauer at the Fairbanks Forecast Office of the National Weather Service. I was inquiring about the difference between "partly cloudy" and "partly sunny." Ted admitted to a bit of subjectivity on the part of the forecaster in the matter, and revealed that it had a lot to do with what the weather had been like for the past few days. In other words, if there had been a streak of really lousy weather at the time of the forecast, but it looked like it might be clearing up, the nod went to "partly sunny." On the other hand, if it had been nice but it looked like some clouds would be showing up in the evening, the outlook was for "partly cloudy."

The subject then turned to the observation that Fairbanks officially enjoyed only three days of clear weather in August, and I wondered how this could be since it seemed to me the sun had been out more than that. Ted explained that the rating is obtained by measuring the… read more

As we move into late summer, the opportunity to observe noctilucent clouds is at its best. Many people who have lived in the northern latitudes for years have probably noticed them before without having a proper appreciation for what they really are.

Noctilucent (night-shining) clouds ride in the sky above 99.9 percent of the atmosphere and over 40 miles above the highest clouds associated with weather. At an average altitude of 50 miles (80 km), they actually skirt the lowest fringes of the aurora, and are above the height at which meteors are observed. For reasons which are not well understood, they occur only at higher latitudes and almost exclusively during the summer months.

Noctilucent clouds are usually seen in the western sky 10 to 20 degrees above the horizon after the sun has set. During this time, the local area is in darkness and nearby clouds appear dark against a lighter sky. Noctilucent clouds, however, are high enough above the earth that they… read more

Who among us has not been frustrated by hearing a Friday weather forecast predicting beautiful weekend weather, only to wake on Saturday and find it raining?

"Experts" predict a wide variety of things, including earthquakes, tornadoes, and the next winner of the Kentucky Derby or presidential election. Frequently, as it develops, they are wrong.

Weather forecasting is probably the oldest of all "sciences," and has played a major part in human history. Unfortunately, even though advanced technology, including the use of satellites, exists, a great deal of credibility is still placed by some individuals on Astrology, which is not a science at all.

More than 4000 years ago, in Babylonian time, weather phenomena were being associated with the planets by priests who calculated the positions of bodies in the sky and developed schemes of weather prediction based largely upon myth.

During the Greek era of the first millennium B.C., more reliable… read more

During the early 19th century, some of the best scientific minds of the period believed that the aurora was caused by the reflection of sunlight from tiny ice crystals suspended high in the atmosphere. It remained for the Norwegian physicist Anders Angstrom (1814-1874) to prove that this could not be true (The term "Angstrom" is probably familiar to high school physics students and to most people who deal with optics. It is a unit of distance used in measuring light wavelengths and is equal to 0.00000001 centimeters).

Angstrom reasoned that, if the aurora was truly reflected sunlight, then it should have the same spectrum as direct light that we receive from the sun. Sunlight, although appearing nearly white to us, is actually a mixture of the visible spectrum ranging through violet, blue, green, yellow, orange and red--the colors found sequentially in a rainbow from sunlight being broken down by raindrops acting as small prisms.

The different colors observed… read more

The late E. L. Keithahn, one time curator of the Alaska Territorial Museum, wrote an-article for the July, 1942 issue of The Alaska Sportsman entitled "There's Magic in the Arctic." It makes interesting reading, not only from a historical viewpoint, but also for his sometimes quaint observations. Here are some excerpts:

"On those Arctic nights when the common auroral arch seems to expand, break up and dance overhead in myriad flaming colors, one experiences a mild electric shock about the ears and hair that is easily distinguished from the nipping of the frost. The air becomes heavily charged with ozone which penetrates the nostrils like chlorine and suggests the smell of blood at a fresh kill. A muffled, swishing sound accompanies these displays. Small Eskimo boys band together and frolic about on the snow attempting to imitate the ominous sounds from overhead. It would be difficult, indeed, to convince these small boys that they weren't hearing anything. No… read more

Fairbanksans and Tanana Valley residents can use their powers of observation to deduce, with a fair degree of reliability, the probability of snowfall when it is cloudy. Just look to the south.

If there is a bright band between the clouds and the Alaska Range, it probably will not snow. If the Alaska Range is obscured by clouds (ice fog doesn't count), or if you can only see the base of the mountains, the chances for snow are good.

Air flowing into the Interior from the south is forced to rise over the mountains. As it does, it drops much of its moisture. Descending into the Tanana Valley, it causes temperatures to rise and some of the clouds evaporate, producing the bright band. Continuing to the north, the air rises again and the clouds thicken, but because the air beneath is warm and dry, little precipitation reaches the ground.

However, clouds moving in rapidly from the west are likely to portend snow. Air moving in from the west encounters no… read more

An aurora is the visible manifestation of an immense electrical current system that is continuously pumping millions of megawatts of electromagnetic and thermal power into the upper polar atmospheres. At times, the current produced exceeds the entire electrical generating capacity of the United States.

Such an astonishing electrical phenomenon and the awesome displays that it creates are a product of the interaction of the solar wind (a hot gas streaming from the sun) and the earth's magnetic field. At the height of an auroral display, the upper atmosphere functions as a gigantic television screen as the air molecules give off light when they are struck by electrons and protons that have been ejected from the surface of the sun a few days earlier. These particles are funneled down along the earth's magnetic field lines into an "auroral oval" surrounding the magnetic poles. The diameter of the oval becomes greater (and the aurora moves further south--or north, in the southern… read more

Having been raised in Nevada, I grew accustomed to the sight of white, puffy clouds drifting high in a dark blue sky. When I settled in Alaska, I was perplexed because the sky didn't seem as blue or the clouds so high.

Relative elevation explained one of the differences. Nevada is at an average elevation of about 5000 feet, while Fairbanks is only at about 500. The intervening layers of atmosphere at lower elevations effectively dull the brilliant blue seen in the mountains where the air is thinner.

But this still did not explain why the clouds seem so much lower. Common sense would seem to dictate that if the ground elevation were lower, the clouds should seem even higher.

The fact is that normal clouds in the Arctic actually do occur lower than they do further south. That portion of the earth's atmosphere in which weather occurs is called the troposphere. As the earth spins on its axis, the troposphere bulges out at the equator due to centrifugal… read more

On July 13 of this year, the earth experienced a massive bombardment of electrically-charged particles (primarily electrons and protons) which had been ejected from the sun a few days earlier during a major solar disturbance.

These periodic outbursts, so annoying to CBers and other shortwave radio operators because of the interference which they create with transmissions, have their beneficial side effects to students and admirers of the aurora. In reality, although a major aurora was produced by the bombardment on July 13, the skies were not dark enough in Alaska for the display to be visually observed.

The spectacle was not overlooked, however, by scientists at the Geophysical Institute or the Electrical Engineering Department at the University of Alaska, or by engineers of the Golden Valley Electric Association on (GVEA).

As industrial growth extends toward higher and higher latitudes, more is constantly being learned about unexpected effects that… read more

The night of September 1, 1859 was one of the most extraordinary of modern times. On this night a great aurora, probably the greatest during the past two hundred years, spread down from the polar regions to cloak two thirds of the entire earth's sky. Even the residents of Cuba saw aurora directly overhead that night.

This spectacular happening followed some hours after another historic event, the first recorded sighting of a solar flare by the unaided human eye. Though recorded separately by two persons located some miles apart, the flare become known as Carrington's Solar Flare after one of the two, English astronomer Richard Carrington.

Carrington spotted the flare when it erupted from a group of sunspots he had been observing on a projected image of the sun. Carrington was quite taken aback by his sighting and could not at first quite believe what he was seeing, since no one had reported such a thing before. Later he recognized that the huge aurora to follow… read more

The air mass that exists over Alaska and Yukon Territory is one of the world's most interesting because a lot of action takes place within it. High mountains, volcanoes, moist Pacific air, the cold Arctic ice pack, the aurora and even the airplanes on the transpolar air route all play a role in what goes on in the air around and above our heads.

The Alaskan landmass separates the Pacific Ocean from the Arctic Ocean with the result, in part influenced by high mountain masses, that Alaska has three climatic zones. The Alaska Range in the south forms the boundary between regions of maritime and continental climate. Similarly, the Brooks Range divides regions of continental and Arctic Polar Basin climate.

Especially when the wind blows over Alaska from the south and southwest, the mountains have great influence. Warm moist air from the Pacific Ocean brings fog and low stratus clouds to the maritime zone. When the moist air tries to rise over the coastal ranges, it… read more

Sometimes one is surprised by the appearance of bright active auroras directly overhead as soon as it gets dark in the evening. When this happens, it is a good bet that the sky will be worth watching the rest of the night. Very likely the aurora will weaken from time to time through the night, but it usually will brighten up and become active again several times.

More usually one notices arcs and bands building up in the northern sky and slowly spreading southward. Especially when several close spaced arcs appear without showing much motion, one should expect spectacular activity to follow within the next few minutes to an hour.

Once the arcs begin to break up into swirling bands, it is common to see fast-moving rays with reddish lower tips racing back and forth along the auroral forms. Then after a few minutes of splendor, the whole scene grows disappointing, and everyone goes back inside the house to warm up.

However, if one will just go back outside… read more

Despite all that is known about the aurora, predicting when the Northern Lights will appear still is a dicey business.

One well-known trend is the 11-year solar cycle auroras are more numerous in years of maximum numbers of sunspots. Right now we are on the decline from a maximum that occurred a year or so ago.

Another cyclic trend relates to the 27-day period of the sun's rotation on its own axis. Sometimes sunspots last for months. Hence one that sprays the earth with aurora-generating solar wind particles on one solar rotation may well do so 27 days later.

There also seems to be a slight tendency for more auroras to occur in spring and fall rather than in summer and winter, owing to the changing annual relationship of earth to the plane of the sun's equator.

When it comes to predicting whether or not spectacular auroras will be seen on any given night, the best bet is to notice what happened the night before. If there was little aurora last night, the… read more

The northern lights are pretty to look at, but we all know that every silver cloud has a cruddy lining. At least it does for the electrical engineer.

One problem is that intense electrical currents in the ionosphere accompany large auroral displays. Sometimes currents as large as a few hundred thousand amperes flow along the aurora, 60 miles above the earth's surface. As these currents wax and wane from minute to minute, they induce voltages in the conducting surface of the earth. The induced voltage can be as large as one volt per kilometer, about six-tenths of a volt per mile.

This voltage also appears in wires such as telegraph or electrical transmission lines which are grounded to earth at each end. The voltage appearing is proportional to the length of the line, hence a long line can acquire a large voltage. A thousand volts will sometimes appear in a line a thousand kilometers long if there are strong auroras overhead.

In the olden days of… read more

Mid-August is the time to again start keeping an eye peeled for Northern Lights. The sky is now beginning to darken enough at night in the northern parts of Alaska and Canada that the aurora can be seen.

If it is dark enough, and if the sky is without cloud cover, the aurora can be seen every night in central and northern Alaska. At any particular moment the aurora might or might not be seen, but if one looks all night long aurora will show up.

Auroras tend to be brightest and most widespread near the peak of the 11- year solar cycle. In late 1981 we should be past the peak of the current cycle but not far past. Even during the minimum years of the cycle, there is plenty of aurora to be seen if one looks for it.

Only three planets in the Solar System have magnetospheres and this is because only Earth, Jupiter and Saturn generate their own magnetic fields. Since the existence of auroras on a planet requires a magnetic field, only Earth, Jupiter and Saturn can have this beautiful phenomenon.

The people of Earth did not know they had a magnetic field until they discovered lodestones and began to use them for navigation. The magnetic field is generated within the earth by electrical currents flowing deep inside it. (Every electric current generates its own magnetic field; a current in a straight wire generates a magnetic field pointed at right angles to the wire; the magnetic field becomes weaker the greater is the distance from the wire).

As far as is known, people do not directly sense the earth's magnetic field, although there is now strong evidence that the birds do it, bees do, and even sewage bacteria move in directions dictated by the local magnetic field. People… read more

By glowing red on Sunday night, April 12, 1981, the heavens over the United States displayed their pleasure with the successful flight of the shuttle Columbia. Perhaps because Columbia was up that night, more Americans than usual looked up at the sky and saw the red aurora that covered much of the nation, even as far south as Texas.

Unlike we northerners who are used to such sights, many Americans did not recognize the aurora for what it was. The Associated Press put out a story with conflicting statements about the event. Many observers thought the red light in the sky was caused by the shuttle's passage. Some thought the shuttle had crashed and caused the lights. Others offered explanations that included the coming of the Martians, the end of the world and the second coming of Christ.

The AP story even quoted a Tacoma, Washington, meteorologist as saying it must have been a display of noctilucent clouds because the aurora borealis doesn't travel east and west… read more

One of the aurora's mysteries that took a long time to solve was the nature of the ray structure often seen in auroral arcs and bands.

Standing in the aurora like pickets in a fence, the rays sometimes move sideways across the arcs and bands at high speeds. Sometimes one even sees them appear to move past each other both to the left and the right.

Rays line up along the direction of the earth's magnetic field, which points nearly vertically and somewhat to the northeast over Alaska and western Canada. To recognize the cross-sectional shapes of the rays, one needs to see them directly overhead in the sky. When they are in that position, they don't look like rays anymore; one reason why it took so long to discover their true shapes.

Not until very sensitive, high-speed television cameras were aimed at the bottoms of rays overhead was the mystery resolved. This solution to the enigma yielded a masters degree for now-a-Ph.D. Tom Hallinan of the Geophysical… read more

Though most of us see the aurora only occasionally, the aurora is, in fact, a permanent feature of the earth. It is always there to see if one is in the right place and darkness conditions permit.

Twin halos called the auroral ovals encircle the two polar regions of the earth. Each oval consists of a band of hard-to-see auroral glow within which are embedded visible auroral arcs, bands and other shapes. The oval in the southern hemisphere is nearly a carbon copy of the one in the north, so when one sees an aurora, he or she can be certain that a similar aurora is occurring in the other hemisphere at the same time. This statement is not quite correct because observations have shown that when a particularly extensive and bright aurora is in one hemisphere the exact counterpart to it in the other might not be found, or at least not at the expected location.

The two auroral ovals pivot around the earth's geomagnetic poles, located near Thule, Greenland and Vostok,… read more

Proof that scientists really do understand the direct cause of the Northern Lights comes from a series of rocket experiments performed in Alaska, Hawaii, Virginia and elsewhere in the world.

The first experiment was at the NASA rocket base at Wallops Island, Virginia, in 1969. An electron gun, a device capable of shooting out beams of high-speed electrons, was placed in the nose cone of a rocket and lofted high above most of the atmosphere. Using gas jets, the rocket payload was rotated until it pointed downward along the direction of the earth's magnetic field, which, even as far south as Virginia, points more downward than northward.

When all was ready, bursts of electrons were shot from the gun. Traveling at speeds near twenty thousand miles per hour, the electrons followed the direction of the magnetic field and penetrated the atmosphere. There they struck the atoms and molecules of the atmosphere and made them glow, producing the first controlled man-made… read more

The approach to the use of English and metric units in the articles appearing here usually is that of the political mugwumps of a century ago. As older persons will recall, a mugwump was one who stood on the political fence with his "mug" on one side and his "wump" on the other, and was afraid to come down on either side.

My main excuse for the balancing act is that this column appears in newspapers in both Alaska and Canada, so it is desirable to mix the units, or use both, to accommodate readers on both sides of the boundary. This practice of course creates some awkwardness.

Unfortunately it contributes to errors, too. Editors who try to eliminate one or the other sets of units make errors, and I do, too. My most recent goof appeared several weeks ago in an article on why local differences in air temperature occur. In that article I correctly stated that the adiabatic lapse rate was 0.6°C per 100 meters. But my conversion to degrees… read more

Although all data from far-flung stations are not yet available, it is possible to piece together a description of the unusual auroral display of December 19, 1980 using reports from those who saw the display and instrumental data acquired at Fairbanks and Fort Yukon, Alaska. Aside from the rarity of the blood-red auroras, this display is of special interest because it induced very large currents in the electrical transmission line between Nenana and Fairbanks between 5:00 am and 7:00 am on the morning of December 19 (Alaska standard time).

Black and white pictures taken each minute by an all-sky camera at Fort Yukon showed that a normally appearing auroral arc--probably a green one--developed directly overhead that location just after 7:00 p.m. on the evening of December 18, 1980. Several arcs and bands swirled overhead Fort Yukon during the next hour, not an unusual occurrence at that auroral zone location. The aurora then quieted down.

The first hint that this… read more

The magnetic storm is about the first of several aspects of the earth's environment to be recognized as caused by variations on the sun. During the last century, people noticed that there were occasional periods of a day or longer when the magnetic field of the earth changed in strength and direction. They called these periods magnetic storms.

Later, scientists realized that the times of magnetic storm were the times of most extensive auroral displays, and they realized that magnetic storms typically followed, by a day or two, large flares on the sun. When radio came into use about 60 years ago, people soon found that long-distance radio propagation was erratic or impossible during magnetic storms.

Erupting solar flares, typically associated with major sunspots, spew out large numbers of charged particles, mostly electrons and protons which stream outward to the earth to create the magnetic storms and related phenomena.

During storms, intense electrical… read more

In locations such as Fairbanks, where protecting hills still winter winds, dramatic differences in air temperature develop at various ground elevations. Furthermore, at a single location, in midwinter, the passage of a few hours time can result in a substantial temperature change even though there is little diurnal variation in solar heating.

The cause of these differences and temporal changes is the development and decay of inversions in air temperature. About half the time, there is no inversion in a locality such as Fairbanks. Then, if there is no wind or change in weather, the vertical profile of air temperature shows a fall with increasing altitude at a rate of approximately 0.6°C per 100 meters (0.3°F per 100 feet). This is the so-called adiabatic lapse rate. An air column with this temperature distribution is stable, that is, there will be no tendency for air in the column to move up or down. Consequently, this is the temperature distribution that would pertain if… read more

Written records telling of the observation of great auroral displays extend back to Roman times in the western world and to well beyond that in the Orient. Even as far back as the seventh century, there are written accounts of aurora being seen at middle latitudes in both the eastern and western worlds.

All this is of more than casual interest because the written record of great auroral displays over the past 1,500 years indicates changing levels of auroral activity. The change can be the result of long-term variations in sunspot activity and can also be due to long-term variations in the earth's magnetic field. Very likely, solar variability is the main cause. Since solar variability also affects weather, any insight into that variability acquired through study of auroral history can have consequence beyond just learning more about the aurora.

Another line of evidence on variation in solar activity appears in the content of radioactive carbon (Carbon-14)… read more

Early on the morning of December 19, 1980, a blood-red auroral arc suddenly appeared in the skies over British Columbia, Yukon Territory and Alaska. Because of the hour--the event started about 6:20 am, Pacific time, 4:20 am Alaska time--not many people were up to see it, even though it lasted for some time and was seen in central Alaska as late as 7:00 am.

Totally-red auroras occur infrequently, not more than a few have been seen in this part of the world during the last twenty years. The most widely-seen in North America in recent times was the spectacular red aurora of February 11, 1958. That night the sky over almost all of the continent was clear, so millions of Americans and Canadians, even those as far south as Florida and southern California, saw this beautiful display. All night long, the Alaskan sky was filled with red aurora so bright it made the snow on the ground look red.

All-red auroras are seen near the beginnings of large magnetic storms, and… read more

Many years ago people gave the name magnetic storms to those intervals lasting a few days wherein there appear the most extensive auroral displays and during which marked variations in the earth's magnetic field occur. A more recent discovery, made some years ago by Dr. Syun-Ichi Akasofu of the Geophysical Institute, is that magnetic storms contain shorter periods of increased activity, called magnetic substorms or auroral substorms.

Substorms typically last about an hour or so. When a substorm begins, the number of auroras seen in the sky may increase, and those that exist will brighten perceptibly. Rapid motions within the auroral forms and violent motion of the forms themselves occur. In a few minutes' time, the aurora can change from barely noticeable to a brilliant display extending across the visible sky.

Observations from satellites and from widely-spaced observing points on the earth's surface show that substorms typically originate at the auroral zone on… read more

A remaining mystery of the aurora is the reason why the thin auroral arc is the most common shape seen. Arcs stand in the sky like giant ribbons set on edge. In length they often extend from horizon to horizon, a distance of a thousand kilometers or more; sometimes arcs are several thousand kilometers long. Arcs reach upward from their lower borders in the direction of the magnetic field, which at auroral zone latitudes is nearly vertical. The height extent of the arc is usually a few tens of kilometers and sometimes far in excess of a hundred kilometers

Considering the great length and height extent of arcs, it is truly amazing that they sometimes are less than a hundred meters thick. Furthermore, the brighter an arc becomes the thinner the structure is. As yet, there is no universally accepted theory that explains this extreme thinness.

Seeing an arc low in the northern or southern sky, one is unable to discern the arc's thickness. Only when the arc sweeps up… read more

Since the Northern Lights rarely, if ever, reach down below altitude 60 km (about 38 miles), the earthbound observer is unable to perceive that the aurora has depth. The bottom of the aurora typically lies near altitude 100 km and its top is usually several tens of kilometers, sometimes several hundreds of kilometers, higher. But when it comes to viewing an object this far away, a person's eyes are too close together to permit visual depth perception. In effect, two eyes are no better than one for viewing objects so far away.

Two scientists at the Geophysical Institute have solved the problem by using two sensitive televisions to record auroral images. Dr. Tom Hallinan operates one camera located atop the Geophysical Institute and Professor Hans Nielsen operates another at his home two kilometers away. Both cameras are aimed in the same direction so that they see the same aurora. The pictures obtained by Professor Nielsen's televisor set are transmitted over a radio link… read more

Only during the last decade, when highly sophisticated satellites began to circle the polar regions, have we become aware that the aurora is a truly continuous part of the earth's environment. A person on the ground can see only a comparatively small part of the polar atmosphere wherein the Northern Lights reside, but the properly instrumented satellite can skim across the polar region to look downward and detect whatever aurora exists, wherever it may be. These satellites find that the aurora is always there.

Twin auroral halos crown the two polar regions. Each sits atop the denser part of the atmosphere, rarely penetrating down to altitudes below 70 km (40 miles): more usually the base of the aurora is near altitude 100 km. Called the auroral ovals, the two halos often consist of weak, parallel arcs embedded in a diffuse auroral glow a few hundred kilometers in width. At such times, the auroral ovals typically have diameter of only four or five thousand kilometers.… read more

Just as bright auroras come and go in the night sky, major auroral displays flit in and out among the years according to the prevalence of spots on the sun. Those persons living at moderate latitudes in the time from about 1640 to 1720 had little chance to see Northern Lights simply because very few of significance occurred.

The whole of the eighteenth century was a good time for auroras. Even then, because of the 11-year cycle of solar activity, some years were better than others. Auroral observing was not quite so rewarding for most at the outset of the 1800s, but it improved during the last half of that century, peaking in about 1870.

Surprisingly enough, records of sunspot activity show that the Klondike Goldrush era, 1896 to 1902, was a low time for the aurora. Nevertheless, the people who wintered over in Dawson, the Fortymile or other northern gold camps saw plenty of aurora. Robert Service certainly saw enough to cause him to spice up many of his poems… read more

The name "black aurora" was coined mostly in fun by graduate students and others at the Geophysical Institute, somewhat more than 20 years ago.

When making visual observations of the northern lights, these observers noticed that there sometimes occurred overhead in the sky what appeared to be close-spaced auroral forms with unusually black dark spaces between them. This situation did not occur often, but when it did, the auroral display seemed distinctive enough that people recognized it as special and commented about the apparent blackness of the sky between the auroras.

Being aware that the human eye and brain combination has a remarkable ability to distinguish between different shades of grey, the young observers thought that the apparent blackness between the auroras was not real, instead that it was an optical illusion. So as a joke aimed at themselves and their own limitations, and because the whole concept was obviously ridiculous, the students applied… read more

We have been taught that dramatic changes to the earth's surface can be created by almost imperceptible processes acting for very long times; e.g., a tiny stream flowing for millions of years can carve out a large valley. This concept is so embodied in our thinking that it is easy to forget that many geologic processes act in an altogether observable, though intermittent, fashion.

Mount St. Helens is a particularly good example. The mountain is a thousand-year accumulation of ash falls, lava flows and pyroclastic (hot avalanche) flows. Each fall or flow is a perceptible event if someone is there watching, but each forms only a tiny, perhaps almost insignificant part of the whole mountain. And of course, much of the top of the mountain slid or blew away in just a few minutes on May 18, 1980.

Less dramatic but similarly intermittent are the geologic processes that utilize wind and water to erode away or build up coastlines. These days, because of petroleum… read more

The Northern Lights and the aurora borealis are two names for the same thing. The term aurora borealis was first used by Galileo in 1619 to suggest the likeness of the northern lights to an early dawn in the northern sky, an appearance it sometimes has to those who live at low or intermediate latitudes in the northern hemisphere.

Once the term aurora borealis was introduced, Galileo and others used it as the name for the Northern Lights. The early history of auroral terminology is somewhat clouded because, at the time, Galileo was already under duress from the Roman Inquisition and was not supposed to be writing on astronomical matters. Therefore, his writings on the subject were appearing under the name of his student, Mario Guiducci. Galileo referenced the aurora as part of his arguments against the established idea that the earth was the center of the Universe. He wrongly thought that the aurora is caused by sunlight reflecting from the high atmosphere.

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The sky provides no guides to give the visual observer depth perception. Consequently an observer of the aurora cannot tell how high the aurora is above him nor can he determine the true shape of the configurations being seen.

However if one knows ahead of time the normal shapes and orientations of auroral forms, an observer can more readily follow and understand the changes that occur in a display, and also better appreciate the true size of auroral phenomena.

Those long arches that extend roughly east-west (actually magnetic east-west) from horizon to horizon are called arcs. If of nonuniform curvature, these forms are called bands. No really meaningful difference exists between arcs and bands, except that the more convoluted form, the band, is often brighter than the arc, and the appearance of bands usually signifies that the overall display is becoming more active.

Arcs and bands are thin ribbons set on edge parallel to the ground. The thickness of… read more

There can be no doubt that some people hear swishing or crackling sounds accompanying bright auroral displays. Usually the reports indicate that the aurora is directly overhead and fast-moving when the sounds are heard.

Since the aurora is at high altitude where the air is too thin to effectively transmit sound waves to the ground, it is certain that no audible sound is produced by the aurora itself. One possibility is that electric fields produced on or near the ground surface by the aurora are somehow causing audible sound.

Another suggestion is that the sounds are a form of self-delusion. The idea here is that one is so used to fast-moving objects also making sound that he or she assumes the fast-moving aurora makes a sound and thereby 'hears' a sound. Yet another idea is that there is perhaps no real sound but that electromagnetic fields produced by the aurora might create the sensation of sound within a person's nervous system.

Recently, Dr. Juan G… read more

When one lacks knowledge about the climate of the past, the safest guess as to what the climate might have been is to assume it is the same as now. But knowledge is accumulating to suggest that things were not always as they are at present.

Tree ring growth over the past 2,000 years indicates several serious droughts between 500 A.D. and 1700 A.D. In North America particularly severe droughts began near the years 510, 610, 830, 860, 1165, 1276, 1390, 1495, 1570 and about 1625 A.D.

During the droughtless eleventh century northern Alaska was several degrees warmer in summer than it is now, but during the more drought ridden sixteenth century, tree ring growth rates show the Mackenzie Valley and northern Alaska had colder summers than exist currently.

Evidently, since about 1670, North America has not experienced any truly great droughts such as occurred in the centuries before. Most of those early severe droughts lasted ten to twenty years, so they surely… read more

One of the stranger kinds of aurora is one rarely recognized by eye. Called flickering aurora by the University of Alaska researchers who first described it, this aurora undergoes rapid change somewhat akin to that seen when a candle's flame is struck by a sudden draft of air.

After more than a year of recording flickering auroras on sensitive television systems used to observe the night sky, the flickering aurora was finally recognized as being something other than a problem with the TV sets. The crucial observation came one night in 1966 when such an intense display of flickering aurora occurred that it was easily seen by the unaided eye as well as the sensitive TV systems.

Flickering occurs only near the time of the auroral breakup, this is the time when quiet auroral arcs rapidly grow brighter and twist into contorted shapes that sweep across the sky. Why flickering occurs only at this time and why it occurs at all are unknown.

Curiously, in each… read more

In the space of an hour, the summer sun rises in the north and swings around the horizon to dip again below the hills off to the north; the sky grows dark and the stars come out; the winter sun peeks above snow-clad mountains, scoots a few degrees westward and sets again; finally the aurora comes out to flash across the Big Dipper and paint colors across the darkened sky from horizon to horizon.

A fanciful impossibility? Not quite. The technology now exists to build in Alaska special viewing rooms that go beyond conventional planetariums. The starting point is a conventional planetarium consisting of a 30- to 40-foot diameter hemispherical dome beneath which 60 people could sit comfortably. Commercially available systems can project onto the inside of the dome images of the stars and the planets. Also commercially available are projectors that display cloud patterns and other sky scenes (the so-called atmospherium).

The next step is convert the planetarium and… read more

Like blue-white spider webs laced across the twilight sky, noctilucent clouds form a wispy filigree in the heavens. Truly a polar phenomenon, noctilucent clouds are never seen at latitudes below 45°. Thus, in North America, noctilucent clouds are pretty much the property of Alaska and Canada.

Nor are noctilucent clouds an everyday occurrence. In 1885, they were first recognized as something strange in the sky. Since then more than a thousand sightings have been recorded in the world. Several displays occurred over central Alaska in the summer of 1979.

The characteristic that distinguishes noctilucent clouds from all others is their remarkably high altitude, 82 (plus or minus a few) kilometers (about 50 miles). Rarely do normal clouds extend as high as 15 kilometers. Noctilucent clouds are seen only in deep twilight, when the sun is 6° to 16° below the horizon. Then the sky is dark enough for the thin noctilucent clouds to be seen and yet the sun is still in… read more

A raining down of hailstones as large as golfballs--or even baseballs, will quickly destroy crops, maim or kill animals and damage roofs. How do such large hailstones materialize out of thin air?

A clue to the formation of hailstones is seen when a hailstone is cut in half. Most show an onion-like layering of alternating clear and opaque ice. This layering demonstrates that the stone is built up by coatings of ice successively frozen onto the surface of the hailstone. Each coating evidences a buildup in an environment different from that in which the coat below formed. Clear ice forms in the part of the cloud where water is copious; ice with many trapped air bubbles, hence opaque, forms in drier portions.

Important to the buildup of hailstones is the existence in thunderhead clouds of supercooled water: water that remains in liquid form well below normal freezing temperature. Supercooled water droplets colliding with a foreign object--a piece of dirt, an… read more

Even during fair weather, small puffy clouds are common in northern skies. A warm area on the ground surface creates an updraft carrying moisture up which condenses to form clouds. Each cloud might last only a few minutes, especially if the nearby air is dry.

But when the moisture content of the middle atmosphere is high, and if the temperature decreases rapidly with altitude, minor updrafts can develop into major upward convective flows. Tall thunderclouds appear, reaching to altitudes above 20,000 feet (6,000 meters) as air rushes upward carrying moisture high above the freezing level.

In the upper part of the cloud the moisture particles condense into water droplets and ice particles. For a time these may be carried upward on the rising air. As the droplets and particles grow in size they become so heavy that the pull of gravity becomes stronger than the force of the upward-rushing air. Then as the particles fall, they drag against… read more

Tropical islands often are the locations of lightning storms, but lightning is rarely seen in the Aleutian Islands. Residents of Adak have asked for an explanation of why this is through a teacher who has spent some time there, Virginia Van den Noort.

Lightning is an electrical discharge of the air that can occur only when the atmospheric electric field is strong enough to break down the air. Such strong electric fields develop only when there is considerable vertical mixing of the air.

A condition that leads to thunderstorms and lightning is one where the ground surface is warmer than the air just above it. The ground warms the near-surface air, which then rises causing an overturn of the air mass. Upward-moving air together with downward- falling water droplets are thought to create the high electric fields required for production of lightning.

Such conditions occur over tropical islands and over warm land masses. But in the North Pacific, in the… read more

Weather and climate link closely together since climate is nothing more than the longtime average of the weather. By weather, we mean the air temperature, air humidity, wind, cloudiness, storminess and any other condition of the atmosphere.

If the weather is unusual a few years in a row, one wonders if a long-term climatic change is being signaled. Usually that seems not to be the case because there are cyclic or quasi-cyclic variations of atmospheric conditions. Short cycles--measured in tens or hundreds of days--might be thought of as weather cycles. Cycles lasting years obviously can be thought of as climatic.

Searches through old ships' logs and other historical documents dating back to 1700 have allowed identification of a climatic cycle near 30 to 40 years long. Changes of patterns of wind strength over the Pacific Ocean and ocean temperature show this cycle, according to Dr. Joseph Fletcher, discoverer of Fletcher's Ice Island (Ice Island T-3). He… read more

A characteristic of life in the north is the small daily range in air temperature, at least compared to regions to the south.

The main reason for the relative constancy of air temperature is the comparatively small change in solar elevation each day at high latitude. In the extreme, above the Arctic Circle, the sun does not come up at all in midwinter and so provides no warming heat. In midsummer, the sun scoots around the sky without changing its elevation angle by more than a few tens of degrees.

When the sun is low in the sky a large fraction of the energy in sunlight is absorbed by the atmosphere. Also, the sunlight that does get through strikes a larger area of the ground. Consequently a unit area of ground surface receives far less solar energy when the sun is near the horizon than when the sun is high overhead.

Even when the sun is directly overhead (elevation angle 90°), only about 60% of the sun's energy impinging upon the earth's atmosphere… read more

Wind-driven ocean currents behave in ways that, at first appearance do not make sense.

In thinking about the wind blowing over the ocean's surface, one easily recognizes that the moving air exerts a force on the top of the water in the direction the wind blows. Seems obvious that the water should move that direction, too, doesn't it? In fact, the water at the surface will move at an angle to the wind direction.

The reason for the deviation is that the daily rotation of the earth about its axis exerts an additional force on the moving water. That force is at right angles to the direction of the water's motion and is directly proportional to the speed of the water. The combination of this so-called Coriolis force and the force of the wind results in the water surface moving at a 45 degree angle to the wind direction--to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

To make matters more complicated, the moving surface… read more

Weather prediction is probably nearly as old as mankind. Which has advanced farthest over the years is perhaps a matter of conjecture. In EDIS, a publication of the National Oceanographic and Atmospheric Administration, Patrick Hughes notes that as early as Babylonian time, circa 2100 B.C., weather phenomena were being associated with the positions of heavenly bodies. At that time, weather prediction was done by priests who developed schemes of astrological-meteorological prediction, and weather prediction was based mostly upon myth. By 750 B.C. the Greeks were beginning to codify sound predictive techniques based upon observational experience. Later, the Romans included weather "signs" in handbooks and almanacs prepared for farmers.

No doubt the most serious weather forecasters were those feudal astrologers who, after the fall of the Roman Empire, were responsible for forecasting weather for military campaigns. If the forecaster made the correct forecast and the… read more

The ups and downs of the 11-year sunspot cycle are somewhat unpredictable. During 1978, the number of sunspots per month rose dramatically and contributed to more auroras and more radio interference in the polar regions. The maximum of the current cycle is predicted for winter 1979-80.

Why have CB communications been particularly difficult in Alaska the past few months? The answer to this question posed by Mr. C. A. Boyd of the Delta Junction area involves the ways of both Man and Nature.

Citizens Band is intended for local, essentially line-of-sight communications. The frequency range for the most popular CB band, near 27 megahertz, is particularly suited to portable short-distance communication. This band is high enough in frequency to permit short antennas and lightweight transmitters and receivers--the higher one goes in frequency, the smaller become the equipment and the power requirements. It is also more costly to build CB equipment designed for high… read more

Nowadays we use the name aurora polaris to describe the whole of the earth's aurora and call the auroras of the northern hemisphere the aurora borealis and those of the southern hemisphere the aurora australis. These three terms make a neat package. They and their meanings so logically fit together in an orderly unified way that it is easy to assume that this grouping was all carefully thought out by some methodical person. But, of course, that is not the way it happened.

New insight into the origin of the term aurora borealis is given in a short article in the December 197S issue of EOS, a publication of the American Geophysical Union. Editor Alton F. Spilhaus, Jr., wanted to entitle the article "More Than Anyone Would Ever Care to Know About the Origin of 'Aurora Borealis,"' but author George L. Siscoe objected, so they chose a more sedate title for Siscoe's article.

According to Siscoe, the term aurora borealis was first used as a metaphor by Galileo in… read more

It is no surprise that comparatively few people have ever seen pulsating aurora, even though it is one of the more common, if not the most common, type of northern lights. One reason is that the pulsating aurora normally occurs late in the night, usually from about midnight to dawn, when most everyone is, or should be, tucked into bed. Another reason is that pulsating aurora is relatively weak. Even during a strong display of pulsating aurora, a person looking up at the sky immediately after leaving a lighted room will usually fail to see this weak aurora.

Pulsating aurora does not swish across the sky like the bright, active auroras typically seen earlier in the night. It just blinks on and off, for reasons that auroral scientists do not yet understand.

Both pulsating arcs and patches are seen; the most obvious to the human observer are large pulsating patches, usually bigger than the Big Dipper from handle to cup. These patches blink on and off every few… read more

The aurora is another reason, besides cheaper fares and good ongoing connections, to take those late night flights between Anchorage or Fairbanks and Seattle. A person sitting in a window seat on the proper side of the airplane can have a grandstand seat on one of Nature's finer spectacles.

At altitude 30,000 feet (10 km), most of the earth's atmosphere is below the airplane where it cannot shield out the auroral light. Consequently, any auroras seen will be roughly twice as bright as they would be observed at ground level.

On a night of average auroral activity, the aurora will be to the east-northeast or north of an aircraft flying between Seattle and Alaska's major cities. Therefore, the best auroral watching is from a left-hand seat flying south to Seattle or a right-hand seat when flying north. Cabin lights reflecting off the aircraft windows can prevent one from seeing the northern lights well, but a blanket held up as a shield eliminates this problem.… read more

One of the elusive mysteries of the aurora is the question of auroral sound. So far, no person has made a truly comprehensive investigation of this problem or managed to record sounds in the audio range that could be associated with the northern lights. Yet many northerners have received the sensation of sound while observing bright, fast-moving auroras overhead. When something moves rapidly, one is inclined to think it should make a noise. That idea might explain some observations. But there are reported instances of people hearing the sounds before becoming aware of the aurora overhead.

People who are used to listening to the sounds of the wilderness away from the noisy background of urban living are most likely to have heard aurorally associated sound usually described as a rustling or crackling noise. Also, women and young people tend to report the sounds more often than older people or men. This tendency suggests that the auroral noise may be at the high-frequency… read more

Changes in sky color have long been known to portend change in the local weather. There is good reason for this association since changes in sky color can be caused by the movement of heavy cloud decks, and heavy clouds often produce rain, snow and lightning.

Such an instance was reported by residents of Kodiak who saw a peculiar green sky for about a half-hour during late evening in July 1978. Immediately following the appearance of the green sky, a rainstorm with much thunder and lightning struck the area.

Sky coloration is caused by the scattering of sunlight as it passes through the atmosphere. As we view the sky it is the scattered light that we are seeing. If there are no clouds in the sky, the sun illuminates all of the air near an observer and thereby causes his eye to receive scattered light from all parts of the atmosphere.

But the brightest light is that which has traveled the shortest distance through the atmosphere, the light that comes down… read more

Every weather forecaster wishes he could do as well as did Lieutenant S. M. Saxby of the British Navy one day in November 1868. He predicted, nearly a year in advance, that on October 5, 1869, the northeastern United States would experience an exceptionally violent hurricane with abnormal tides. A friend predicted the landfall of this storm to be Halifax, Nova Scotia. Sure enough, within 12 hours of the designated time a hurricane of great violence did strike, and it landed within 100 miles of Halifax.

Lt. Saxby stated that his prediction was based upon the moon's position. He knew that on October 5, 1879, the moon would be at its closest approach to earth, and it also would be very nearly on the line joining the center of the earth to the sun--conditions that cause the moon and the sun to pull best in unison to create the highest tides. Thus, Saxby's prediction of abnormal tides on October 5 was firmly based on known facts.

About the basis for his prediction of… read more

Fata Morgana, also known as Morgan le Fay, was a fairy enchantress skilled in the art of changing shape. In one traditional story she was King Arthur's sister and learned many of her skills from Merlin the Magician.

A special type of complex mirage, one that sometimes gives the impression of a castle half in the air and half in the sea, is named after Fata Morgana. She was known to live in a marvelous castle under the sea. Sometimes the enchantress made this castle appear reflected up in the air, causing seamen who mistook it for a safe harbor to be lured to their deaths.

The fate morgana mirage is one that can occur only where there are alternating warm and cold layers of air near the ground or water surface. Instead of traveling straight through these layers, light is bent towards the colder, hence denser, air. The result can be a rather complicated light path and a strange image of a distant object. A fate morgana actually is a superposition of several images… read more

When a major auroral display spreads across Alaska's skies, intense electric currents flow in the ionosphere about 110 km (70 miles) above the earth's surface. Sometimes a current as large as a half-million amperes flows, usually east-west, across Alaska and Canada.

If we could just get some of this auroral juice into our power lines it would seem like we might have a good thing going. The truth is that it does get into our power lines. Unfortunately, the end effect is more likely to increase rather than decrease our power bills.

The electrical currents in the ionosphere induce additional currents in the conducting surface of the earth and in any nearby conductors such as power lines and pipelines. Long conductors, particularly those running north-south, pick up the greatest current. Hence appreciable current flows in the Alyeska pipeline. Recent measurements of current in the power line running from the mine-mouth coal generating plant at Healy northward to… read more

Dust devils form most frequently in desert areas where the sun beats down on the poorly conducting sand surface. As Meg Hayes of Fairbanks has noted, they also occur in non-vegetated areas such as parking lots, especially if there are nearby large buildings to help cause irregular air currents. The hot desert or parking lot surface heats a thin layer of air just above--setting the stage for the dance of the sun devils.

Even though the hot near-surface air wants to rise up through the cooler, and therefore heavier, air above, quiet air tends to retain a degree of stability--a resistance to new air motion. One can visualize that resistance as something like the surface tension on water--it is strong but it does have a breaking point.

As the stability limit is approached, almost any sort of irregularity can cause the limit to be exceeded so that a bubble of hot surface air bursts upward. A place on the ground that is hotter than elsewhere will cause the limit to be… read more

On April 12, 1978, the national news media distributed the prediction that extensive auroras and radio blackout would cover much of the world. The reason for the prediction was the occurrence of a giant flare on the sun the day before, the largest flare to be observed in several years.

Solar flares jet out high-speed clouds of electrons and protons that reach to the earth's orbit in a day or two. If these clouds are aimed to hit the earth, a portion of them penetrates through the earth's magnetic field to strike the polar atmospheres. There, auroras and disturbances to the radio wave-reflecting ionosphere are caused.

On the night of April 13, big auroras were supposed to be seen far equator-ward of their normal high-latitude habitats. But these auroras were not seen.

The problem was that the solar flare did not occur at the right place on the sun for its ejected cloud to strike the earth. If a large flare develops in the center of the sun, as seen from… read more

Every once in awhile, the forces of the sea and wind combine to produce the rogue wave. A wall of water a hundred or more feet in height, the rogue wave can easily mash the bow of a large ship or break the ship in two.

Writing in Smithsonian Magazine, Peter Britton cites a study of giant waves in the Gulf of Alaska. Waves there are found to be no worse than in the northern North Sea, where extreme wave heights are near 100 feet. However, the study indicates that the maximum possible wave height in the Gulf of Alaska is a terrifying 198 feet.

In a sense, rogue waves are statistical accidents. They form when the crests of several different trains of waves, each with its own speed and direction, all come together at the same time. The wave height at that time is the sum of the heights of the individual waves. Since the individual wave trains are moving at different speeds, the rogue wave cannot last long. Either the waves of which it is made separate or the… read more

Clear, cold winter days in Alaska are conducive to seeing the green flash. Though a bit rare, the green flash happens often enough to pay to look for it just as the sun rises or sets. An observer in Fairbanks recently reported seeing the green flash at sunset when there was a strong temperature inversion (and much ice fog) in the Tanana Valley.

The green flash may last only a second or so near the time when the first edge of the sun comes up in the morning, or the last edge goes down in the evening. The green flash is the result of the atmosphere acting like a weak prism to bend each color of the sun's light by different amounts. The separation of color is small, but sometimes enough to remove from view the red and yellow light coming from the edge of the sun above the horizon. This leaves only blue and green light, but the blue tends to be scattered most by the air. So, if conditions are just right, a portion of pure green sun, the green flash, will be seen briefly. It… read more

Cultural Eskimo views on a person's destination after life vary widely from Alaska to Greenland. Eskimo parents of the Mackenzie region must always remember that the soul of the departed may enter the body of a newborn child where it will remain until death--unless that child be punished too often, in which case the spirit will leave. In other regions, the departed spirit goes to various levels of afterlife, the hereafter depending upon behavior in life and the manner of death.

A person who dies of sickness or other routine cause and who has not been a good person in life generally will end up in a bad place. That place may be beneath the sea or perhaps down in the bowels of the earth. The bad place is not necessarily a site for punishment, the views differ from Alaska to Greenland, but it may be very dark there, much snow and ice cover the land, and it is always stormy.

In general, it is believed that there is no assurance that life in the final land will be… read more

Only a few years ago almost every meteorologist and auroral physicist scoffed at the suggestion that the earth's weather might be influenced by variations in sunspots. True, statistical relationships between the 11-year cycle in sunspot occurrence and weather or climatic phenomena were being claimed. But it was common knowledge that one could find 11-year cycles in the stock market, the quality of wines, the length of women's dresses and almost anyplace one chose to look.

The problem has been that scientists could find no mechanism by which the particles streaming from the sun in association with sunspot variability could have an influence on weather or climate, even though these particles were known to create auroras and other so-called solar-terrestrial effects.

It seems to be characteristic of scientists that they are skeptical of apparent associations between different phenomena if it is not obvious why the two phenomena should be related. But give a… read more

Like many others, J. Raymond of Fairbanks has noted the vagaries of AM radio reception in Alaska and has asked if reception is better in Alaska than elsewhere. He rightly notes that the peculiarities of broadcast band radio in Alaska are related to the aurora.

Those same incoming charged particles (mainly electrons) that stream down along the direction of the earth's magnetic field over central and northern Alaska to create the visible aurora also modify the ionosphere. Irregularly shaped regions of enhanced electron density associated with aurora in the ionosphere, altitude 100 km (60 mi.) and above, both absorb and reflect radio waves.

For the most part, the auroral particles interfere with ionospheric radio propagation, making it less reliable in Alaska and other polar regions than at lower latitudes. But sometimes the auroral effects lead to weird and wondrous propagation paths. This is why listeners in Chalkyitsik sometimes receive AM radio from Hungary,… read more

As we move into summer weather, clouds change from widespread layered (or stratus) to a discrete cauliflower type of cumulus cloud. These cumulus clouds, due primarily to ground heating by the sun, otter develop into thunderstorms. Many Alaskan forest fires are caused by lightning from these thunderstorms. Because these fires often remain undetected for a long time, they account for most of the forest acreage burned (about 1 million acres per year.) A single thunderstorm lasts almost 20 minutes. Thunderstorms are associated with updrafts inside and downdrafts below it. These drafts can be as fast as 50 knots. The sudden wind shifts associated with downdrafts under a storm are most dangerous to aircraft.

Thunderstorms do not occur uniformly over the State. Very few, if any, are recorded north of the Brooks Range. Of the few preferred areas, the most extensive thunderstorm formation occurs in the mountainous region between the Yukon and Tanana rivers, extending into Lake… read more

Rather large amounts of power are required to produce the aurora seen in the two polar regions. During a moderate to large auroral display lasting one to three hours the energy dissipated by the auroral processes is about the same as released in a Richter magnitude 6 earthquake, in a cyclone, or in a small nuclear bomb.

It is almost certain that the energy required to power the aurora comes from the sun. From the sun there is a continual outflow of matter in the form of electrons and nuclei of atoms, mostly hydrogen nuclei (protons). This flow, called the solar wind, streams at speeds near 400 km/sec (900,000 mph) and therefore takes severel days to reach the earth, whereas light takes only eight minutes.

Near the earth, the energy of motion within the solar wind is converted to electromagnetic energy--by the same process that an electrical generator converts energy of motion to electrical energy. That energy is again converted to energy of motion of those… read more

All it takes to find the aurora, day or night, is a pair of sticks. Willow wands will not work because the sticks must be conducting. And, instead of walking across the ground with them, one must drive the metal rods into the ground, at locations several hundred feet apart. A wire is attached to each rod and also attached to one post of a sensitive ammeter or voltmeter.

When the aurora appears overhead, a voltage will be induced in the earth between the rods and electricity will flow in the wire attached between the rods and the meter. If the meter has the ability to record the voltages or currents passing through it, a record similar to the one below will be produced.

During quiet times, when there is no aurora, the recording meter will draw a straight line down the center of the graph. When really bright aurora is overhead, the pen of the meter will sweep back and forth across the paper in response to the auroral activity. The meter can be converted into an… read more

Normal June rainfall in Fairbanks is 1.39 inches; June 1967 was slightly drier, 1.10 inches, in consequence of relatively dry air moving northward over the Chugach and Alaska Ranges into interior Alaska.

However, in July 1967 there developed a low north of Alaska and a high in the North Pacific. These combined to create increasing flow of moist ocean air from the southwest so that Fairbanks received 3.34 inches of rain instead of the normal 1.84 inches.

In early August 1967 large-scale pressure patterns developed to enhance the flow of air from the southwest and an inflow of Arctic air from the northwest into northern Alaska. A few days before the flood there occurred a strong movement of warm, moist air into the northwest Pacific from a decaying tropical circulation pattern. This air mass evidently was the real source of the water that created the flood. By August 12, 1967, pressure patterns over Alaska were forcing this wet air toward… read more

Why such a mild early winter in Fairbanks? Why more than 100 inches of rain in Cordova since August? Why the driest fall in 90 years near Seattle? Why unusual cold and storm in the northcentral states?

All these unusual weather patterns are related, and they have a single cause--they are the predictable result of an unusually persistent pattern that has developed these past few months in the air circulation of the Northern Hemisphere.

Normally the upper average jet stream air flow over the Gulf of Alaska is west to east. Having moved across the Pacific Ocean, this air is warm and moist. Its normal flow across the Panhandle and the Pacific Northwest gives the rainfall usually experienced there. Central Alaska in winter normally receives cold air from the north and west, dry air that has swept across Siberia or the ice-covered Arctic Ocean.

The normal west to east flow pattern around the earth at middle… read more

In March of 1973, Nature magazine published a short report on research on global climate changes during the past 20 years or so. It stated that climatologists generally accept the fact that the earth's climate is tending toward an ice age of some sort and that a new North American ice sheet may be forming.

Since we are talking bout the relatively near future, with is the implication for Alaska? Probably not much. Although one tends to think of ice sheets occurring when the weather is very cold everywhere, this is not necessarily true. Even at the height of the last ice age, temperatures around Fairbanks were probably much as they are now. Of course, then as now, one could say that an ice age descends upon Fairbanks every winter.

But a changing climate affects weather patterns also and here Fairbanks shows some effect. Precipitation records for the last 20 years show a steady decrease in rainfall. (1967 was a spectacular exception.) The average annual… read more

The Geophysical Institute's Dr. Takesi Ohtake is proposing to write letters on the clouds, giant letters big enough to be recorded by photo imaging systems on weather satellites. He and coworkers from the Denver Research Institute are hoping to test seeding methods for dissipating the low-level summer clouds along Alaska's arctic coast. These clouds hinder navigation and may also adversely affect the plant and animal life of the northern coast which receives precious little sunshine at best.

Using a light aircraft for seeding operations, Dr. Ohtake and his fellow scientists hope to fly patterns that will produce mile-long holes in the clouds in the form of letters of the alphabet. These then should be recognized by imaging systems on a satellite scheduled to fly over Alaska shortly after the cloud seeding. We wish Dr. Ohtake success and admonish him to keep it clean.

The aurora is one of nature's most beautiful dramas. Played against a cosmic backdrop, the colors and motions are often subtle and quick, but such a show is not difficult to photograph if strict attention is paid to certain procedures which are peculiar to auroral photography.

First, find someplace where you have a clear view of the sky and horizon, away from streetlights. You will need a sturdy tripod, a camera with an f/2.8 lens or faster, a high-speed black and white or color film, and a cable release. The wider angle lenses are easier to work with if they are fast enough.

Between 10:30 p.m. and midnight, you'll have the best chance of seeing the bright arcs and forms which are most photogenic. Pay attention to the foreground; it provides a stable means of composition and orientation, as well as an attractive setting. Use a "night light" in the foreground, such as a cabin window. Regular outside lights are too bright and may overexpose the film during the 3 to… read more

According to some people, the aurora swishes, hisses, sizzles, rustles, rushes, whizzes, crackles, or whispers. It can sound like the tearing of silk, the wind in the trees, the noise of flying birds, the sweeping of sand, or the flapping of a ship's sails. Or it can sound like nothing at all and, in fact, many northerners have insisted that the aurora is soundless, and have questioned the claims of successful auroral auditors.

Carl Lomen, once the "Reindeer King" of the Seward Peninsula, liked to say that observers of the Northern Lights need only close their eyes to shut off sounds imagined while watching the display. David Thompson, an 18th century explorer for the Hudsons' Bay Company, blindfolded his companions during a display because he thought their eyes were deceiving their ears. Sure enough, the sightless men stopped hearing the noise. Other polar explorers (John Franklin, Robert Hood, John Richardson, Elisha Kent Rane, and Vilhjalmur Stefansson among them) have… read more

Listeners of "shortwave" radio bands, ham radio operators and "CBers" all have one thing in common--their activities are interfered with by the aurora.

The same energetic particles that come in from outside the atmosphere to create the visible aurora alter the ionospheric layers that affect radio propagation. These particles have a variety of effects. One is to cause absorption of radio waves that normally would be reflected by the mirror-like ionospheric layers. Then long distance communication that depends upon ionospheric reflection may cease simply because of the absorption. The incoming particles can also create peculiar reflecting regions. In such instances it may be possible for a ham operator in Anchorage to talk with one in Fairbanks even though both their antennas are pointed northward--in such a case they are actually bouncing their signals off the auroral region.

This also is the reason why a "CBer" can sometimes receive signals from distant Alaskan… read more

After corresponding with us, Mrs. Ward Seyler, a retired teacher of Denver, Colorado, decided to come to the Geophysical Institute this month to see the Aurora. Being lucky, she saw a moderate display her first night here. She then spent the next night at Ester Dome Observatory with Dr. Tom Hallinan to watch him observe auroras with television cameras. Their vigil was rewarded with a spectacular multicolored display. The next night Ms. Judy Holland took Mrs. Seyler to Poker Flat to watch rocket launches.

Mrs. Seyler said she had wanted to see the aurora for many years. Next, she said, she wants to see the stars against a really black sky, something that is no longer possible in the Denver area because of air pollution. She plans to go to the Kitt Peak Observatory in Tucson, Arizona for stargazing. Things we in Alaska take for granted, such as aurora and clear skies are special treats for persons like Mrs. Seyler

A reader, Mrs. L. Hollister, reports that a neighbor lady claims to be fairly successful in predicting local wind conditions by observing the nature of the clouds in certain directions from her house. The question is whether such claims make sense and why is it that one sometimes can do better than the experts in predicting weather.

To some extent everyone learns to be an expert on the weather that affects them directly. A person interested in gardening worries about frost and learns within a few years whether his garden location is likely or not to suffer a frost if a frost warning is given. Those who launch rockets from the Poker Flat Research Range have learned to pay attention to weather forecasts, but they have found that nighttime skies are usually clearer than Weather Service predicts.

It does seem true that an observant, self-taught weather watcher can do rather well in many instances, especially if he or she remains in one location for a long time.… read more

August's darkening nighttime skies start making it possible to see auroras again. The Northern Lights have been out all summer but, since April, high sky brightness has made them invisible.

To see them, look for arc-like structures in the northeast and up as high as the zenith. Their changing intensity, motion and perhaps a hint of green or red color make it possible to distinguish auroral forms from thin clouds.

Remember that auroras are best seen when your eyes are dark-adapted, a process that takes several minutes. Once you look at a car headlight or other bright light source, the adaptation is ruined for a few more minutes.

There is a slight tendency for more auroras to occur in spring and fall than in summer and winter.

Extending from the tropics to the polar regions, the continental plains of North America and Asia are the favored locations of tornadoes. Most occur in summer during the daytime; each year they kill hundreds and cause many millions of dollars in damage.

A tornado is a violently revolving funnel cloud usually a few hundred meters in diameter. Intense upward flow of air at its center leads to very low pressure there. The funnel itself is visible because it contains small water droplets formed by cooling and condensation of air expanding into the low pressure region. Heat given up by the condensation evidently provides the energy to drive the rapidly rotating air of the outer funnel at speeds as high as 500 miles per hour.

Buildings explode from the force of the air within when the low pressure of the funnel center passes over them; then the high wind in the outer funnel completes the devastation.

Strange things happen in tornadoes--straw drives through… read more

Ball lighting is one of those strange phenomena that rarely occurs and is not understood. Only in recent years have many scientists accepted ball lightning as other than an illusion; perhaps some still view it as such.

Ball lightning evidently can enter a house through a chimney only to roll harmlessly across the floor with a hissing noise and then vanish with a loud pop. Bright blue in color, golf ball or basketball size, ball lightning can move erratically, sometimes against the wind. Ball lightning probably is a self-contained mass of ionized air held together by its own magnetic field. As such it would be called a plasma rather than a gas, liquid or solid.

Recently a British woman reported she was struck by such an object. Her dress, made of synthetic fiber, was burned through. She received a slight burn on her finger around her wedding band as she brushed the ball away; otherwise she was unhurt.

This energy release from ball lightning is somewhat… read more

Flights of instrumented aircraft over Alaska and south of New Zealand have shown that the southern aurora can duplicate the boreal aurora. Also, the flights have shown that the auroras over Alaska are typically 20-30% brighter.

Putting this observation and others together, scientists at the Geophysical Institute have concluded that the aurora over Alaska and eastern Siberia is probably brighter than over eastern Canada, Iceland and Northern Scandinavia.

An explanation for the difference in brightness with longitude comes from the knowledge that the earth's magnetic field strength varies with longitude. The magnetic field strength helps determine how many electrons and protons can enter the earth's atmosphere to cause the aurora. The more charged particles entering, the brighter the aurora.

It has long been known that large displays of the Aurora Australis occur when there are large displays of Aurora Borealis. Lack of simultaneous observations at conjugate points, points on the two ends of a magnetic field line, long prevented determination of the degree of exactness between Northern and Southern Hemisphere auroras.

Several years ago researchers from the University of Alaska and Los Alamos Scientific Laboratory joined forces to investigate auroral conjugacy. They mounted auroral cameras in long-range jet aircraft based at Anchorage and Christchurch, New Zealand. The aircraft flew simultaneously over carefully designed paths crossing the northern and southern auroral zones. Eighteen such flights showed that the auroras in north and south behave alike and sometimes are exact copies of each other. The degree of exactness and the nature of the differences that do at times occur is useful information that yields a better understanding of the aurora and the… read more

Northern lights and aurora are two names for the same phenomenon. The aurora is caused by charged particles, electrons and protons, striking the earth's atmosphere. These particles stream downward along the earth's magnetic field, which at Fairbanks is nearly vertical.

The particles give energy to the oxygen and nitrogen molecules of the atmosphere. This energy is then given off in the form of light. Green is the main color in the average garden-variety aurora which occurs at an altitude near 100 km. When the incoming particles are especially energetic, they create red light on the lower edges of aurora; such auroras may be as low as 80 km.

Again this year rockets are being flown from Poker Flat Research Range, near Chatanika, to create high-altitude barium releases. Five rockets, each carrying four to twelve releases, are being flown, on clear nights sometime in late March and early April.

Each release ejects a small quantity of barium vapor that is visible from the ground and which permits measurement of the wind and the electric field in the upper atmosphere. The release first appears in the form of a rapidly expanding yellow-green ball. Part of the barium vapor remains neutral and drifts with the wind forming a green cloud. From this cloud a reddish-purple cloud of ionized barium vapor emerges. This cloud drifts away under the influence of the electric field.

Since the releases are at very high altitude, 150-300 km, they can be seen everywhere in central and northern Alaska. When feasible, there is an attempt to notify area radio stations of impending launches so that Alaskans can observe the… read more

Alaska Science Forum's first correspondent, Mrs. Claude Swain, requests comment on The Jupiter Effect, a recent book by two scientists suggesting unusual occurrences of geophysical events in 1982. This book suggests a major increase in auroras with attendant disruption to radio communications, changes in weather patterns and major storms that could devastate coastal cities. It also predicts potentially devastating earthquakes.

The authors of The Jupiter Effect, John Gribben and Stephen Plagemann, suggest a major change in sunspot activity in 1982 due to magnetic and gravitational effects of the planets which, in 1982, will be aligned on one side of the sun. Much evidence exists that such effects will be minor and that 1982 will not be a markedly unusual sunspot year.

The authors then further speculate that the supposed change in sunspot activity will produce major effects on the earth's weather, air circulation and rotation. Though changing sunspot… read more

Strange lights seen in Alaskan skies on late February and early March 1978 evenings have a reasonable explanation. These were chemical releases performed at high altitude aboard rockets flown from the University's Poker Flat rocket range near Fairbanks.

The two most beautiful sequences, on February 27 and March l, were conducted by a group of Danish scientists, the first truly international users of Alaska's scientific rocket range.

Each Danish rocket released a chemical called trimethylaluminate (TMA, for short) as it sped upward through altitude 80 km (50 miles). At this altitude the rocket was still in darkness and the TMA formed a yellowish trail. Then as the rocket entered sunlight, the TMA being released glowed a beautiful blue color.

By photographing the deformation of the TMA trail with cameras at Arctic Village, Fort Yukon and Fairbanks, the Danish scientists measured the wind in the region through which the rocket was flying.

A minute… read more

We keep hearing about the inversion over Fairbanks. What is it?

Normally, the air near the ground is warmer than the air at higher altitude. An inversion is the reverse situation--colder air at ground level than higher up.

Cold air is heavier than warm air. Thus once an inversion forms, the air is very stable. Mixing that would normally occur by the rising of warm air is inhibited. Consequently pollutants such as carbon monoxide, sulfur compounds and ice fog remain trapped near the ground when there is an inversion.

Fairbanks has some of the world's strongest inversions, sometimes 30° to 40° F colder at ground than at several hundred feet above ground.

Fairbanks is surrounded on three sides by hills and has one of the lowest wind conditions in the world. The lack of wind allows the air over the city to remain relatively stagnant.

When the sky is clear, the ground and the air near it radiate heat energy to outer space. Clouds over the city prevent this radiation. That is the reason why, at the same temperature, it feels warmer outside under a cloudy sky than it does when the sky is clear. It is also the reason why you should shutter or curtain your windows on clear nights to prevent radiation to the cold sky.

When the sky is clear, the ground cools and cools the air near it. Thus an inversion forms, an inversion being the condition of higher temperature at altitude than at ground level.

The strongest inversions occur in winter; weaker ones occur in summer when the air is still. During winter nights and days there is an inversion more than 70% of the time.

March is one of the better months to go outside to see the northern lights. The sky is often clear and yet it can be warm enough to enjoy staying out more than a few minutes.

There is a tendency for better auroras in fall and spring. Though the aurora occurs year round over Fairbanks, by mid-April the sky is too light to see the aurora. The best times to watch are between 9:00 pm and 2:00 am, but the aurora can appear anytime during the nights.

The ozone layer--the thin high-altitude shield of O 3 molecules that protects life on earth from damaging solar ultraviolet light--continues in the news. Chemicals released by aerosol spray cans and SST aircraft have the potential to destroy ozone, but just how large these effects are remains controversial.

Now, a recent TIME (February 23, 1976) article cites the effect on ozone of large solar flares. Similar processes occur over Fairbanks when the aurora appears. The same incoming particles (fast electrons and protons) causing the aurora affect the chemistry of the high atmosphere. Nitrogen oxides are formed which attack the ozone.

Consequently, the ozone content of the air over Fairbanks rapidly goes up and down depending upon the amount of aurora. Whether or not this causes us any special problems here is not yet known.

Normally warmer than February, March usually brings many nights of clear sky and northern lights. It is a good time to try your hand at auroral photography.

Use a camera with a lens of f/3.5 or faster and one which permits time exposures. For color photographs, Kodak Hi-Speed Ektachrome is best; for black and while, Kodak Tri-X or any relatively fast panchromatic film works well.

Even with a fast lens and sensitive film, time exposures of a few seconds are necessary, so it is essential to use a tripod to hold the camera steady. Try taking a series of different time exposures, ranging from about 3 sec to 15 sec to gain experience with your camera. With practice you can then alter the exposure depending upon the auroral brightness to get good pictures.

Photographing the aurora is a real challenge, but with luck you will get a few pleasing pictures the first time you try.