NSF OPP (SGER) Grant No. 9872626 to Hajo Eicken, Geophysical Institute, University of Alaska Fairbanks, 6/15/1998-6/15/1999 (overview of research results)

Fluorescent and stable-isotope tracers have been utilized to derive pathways and fluxes of snow and ice meltwater through Arctic summer sea ice. Transport and sequestration of meltwater are of considerable importance in the context of summer ice albedo evolution, the sea-ice mass balance, ice-ocean interaction and the dispersion of pollutants.

Field experiments have been carried out at the SHEBA (Surface Heat Budget of the Arctic) Site during the summer of 1998. The contrasts in the stable-isotopic composition of precipitation, ocean water and sea ice were utilized to derive the residence time of meltwater in surface melt ponds, the invasion of meltwater into the ice from below and the trapping of meltwater in under-ice ponds. Fluorescent tracers (Fluoresceine, Sulforhodamine, Rhodamine) were released to track advective lateral transport of meltwater on and in the ice cover. Longer-term experiments were designed to provide information on the vertical and lateral percolation of meltwater through the upper ice layers and its importance for ice desalination. These data sets were augmented by permeability measurements (as the most important boundary condition controlling flow through the ice matrix) and determination of the hydraulic gradients as the major driving force of fluid flow.

The following results were obtained. (1) Melt pond shape and coverage during the early melt season are controlled by the ice permeability structure in combination with the meltwater production rate and redistribution along the sea-ice topography. (2) Sites of meltwater drainage, composed to more than 60% of melted snow during the first weeks of melt, lead to rapid formation of underwater ice and false bottom formation, trapping a significant fraction of the meltwater under the ice. (3) The tracer studies also show that during the second half of the melt season, lateral transport and invasion of freshwater into the ice cover from below are associated with a significant heat flux and may play an important role in the decay of seasonal sea ice.

Selected presentations and publications

Eicken, H.: Tracer studies of meltwater transport and ablation of Arctic sea ice; Poster Presentation at the SHEBA/FIRE Science Meeting, Tucson, Az., January 1999

Eicken, H.: Ablation and albedo of Arctic summer sea ice: studies of meltwater transport and suggestions for improved albedo parameterization schemes, Presentation at the IARC Workshop on Atmosphere-Ice-Ocean Interaction, Fairbanks, May 1999

Eicken, H. et al.: Tracer studies of Arctic sea-ice growth and ablation, Presentation at the International Union of Geophysicists and Geodesists Symposium, Birmingham, July 1999

Eicken, H. et al.: Indirect measurements of the mass balance of summer Arctic sea ice with an electromagnetic induction technique, Presentation at the International Glaciological Society's Symposium on Sea Ice and Its Interactions with the Ocean, Atmosphere and Biosphere, Fairbanks, June 2000

Eicken, H., W.B. Tucker III, D.K. Perovich (2001) Indirect measurements of the mass balance of summer Arctic sea ice with an elotromagnetic induction technique, Ann. Glaciol., 33, 194-200. (download this paper as an Adobe pdf file)

Eicken H., H. R. Krouse, D. Kadko, and D. K. Perovich (2002) Tracer studies of pathways and rates of meltwater transport through Arctic summer sea ice. J. Geophys. Res., 107(10), 10.1029/2000JC000583. (download this paper as an Adobe pdf file)

Data sets

Sea ice and melt pond data sets resulting out of this project have been transferred to the SHEBA/ARCSS data base and can also be obtained by contacting Hajo Eicken .

Overview and first results

A more detailed description of the project including figures and photographs can be found at:
Tracer studies of meltwater transport and ablation of Arctic sea ice - Overview and first results