Vivian Underhill

2011 JISAO Summer Research Internship

Sea ice distribution in the Bering Sea

Vivian UnderhillI spent the summer working with Dr. Kevin Wood investigating sea ice distribution in the Bering and Chukchi Seas. In particular, we looked at a border of ice about 50 km wide along the Northern Siberian coast, past Wrangell Island and out to the tip of Cape Dezhnev. While this tail of ice occasionally rounds the corner of the cape, it usually seems to break off and get exported into the Bering Sea.  Using historical sea ice maps and modern satellite data, we reconstructed a timeline of the feature’s appearances for the last century. The presence of the SIT seems to be disappearing; in the first half of the century, it was present in about 1/2 of summers, but it has since appeared less frequently: over the past century as a whole, it has appeared only about 1/3 of the time, and hasn’t been seen at all since 1998. 

We reconstructed an index of the SIT’s occurrences over the past century using four different sources: Danish sea ice maps from the beginning of the century, Russian air reconnaissance maps from the 1930s to the present, and two different satellite sources.  Each data set overlaps another in time, so we were able to piece together a single index for the whole time period. We used the 20th-Century and NCEP/NCAR Reanalyses, to investigate possible linkages with larger-scale meteorological and climatological processes. It seems that the presence of this tail of ice could be a proxy index for the presence of the SCC, given that there is a large enough source of multi-year ice. In the future, a record that extends further into the past will help describe this phenomenon more accurately, and continued data on modern wind and current conditions in conjunction with ice distribution will tell us more about these linkages.



Vivian's research poster

Click on poster for full-size image [PDF]