The eastern Laptev and western East Siberian Seas are characterized by substantial river input from major rivers (Lena, Yana, Indigirka, Kolyma) accounting for more than a fifth of the total freshwater supply to the Arctic Ocean and delivering substantial amounts of dissolved and particulate matter to the shelves. The coastal zone in this region is furthermore characterized by some of the highest rates of coastal retreat (meters to >10 m/yr) found anywhere in the Arctic. In this context, coastal sea-ice processes can play an important role in curbing or enhancing land-ocean interaction as well as in the redistribution of particulates supplied to the nearshore zone from coastal erosion and other processes.

As part of this project, we are considering linkages between freshwater discharge and coastal/offshore ice formation as well as their importance for sediment entrainment and transport processes. As with the study of regional and interannual variability of sediment entrainment, we have to rely on remote-sensing data (specifically SAR and AVHRR) to achieve this goal. In particular, the backscatter signatures and zonation of coastal ice types (freshwater, brackish and sea ice, bottomfast ice) were studied in more detail as they pertain to the overall goals of the project. The paper accessible below describes in more detail the methodical aspects of this work. Currently, we are integrating field measurements carried out during the 1999 Russian-German Transdrift VI expedition with remote-sensing data to assess the variability of freshwater dispersal and its impact on ice formation and processes important for sediment transport. The SAR scene of the ice off the Lena Delta provides an indication of the information accessible through radar remote sensing.

Figure 1. Map of the Lena Delta in the southern Laptev Sea. The box marks the region covered by the satellite scene shown in Figure 2.

Figure 2. Radarsat SAR scene of the eastern Lena Delta and adjacent sea ice cover for March 5, 1997. A belt of high-backscatter brackish and freshwater ice lines the entire width of the coast. Also shown are sampling locations (S1-S3) for salinity measurements in the transition between brackish and seawater as well as subregions for detailed analysis of backscatter signatures (for details refer to reference at bottom).

 

A conference proceedings paper summarizing early results of this research can be downloaded as an Adobe pdf file:

Eicken, H., U. Blahak, W. Dierking, I. Dmitrenko (1999) Spatial and temporal variability of SAR backscatter signatures of coastal sea-ice types off the Lena River Delta (Laptev Sea). IGARSS 99. (download this paper as an Adobe pdf file)