The quasi-permanent sea ice cover of the Arctic Ocean is a central component of the northern high latitude climate system, and secular changes in the concentration and thickness of the sea ice can be important proxy indicators of wide-spread arctic climate variations. While interannual differences in ice concentration and extent are relatively easily documented from microwave satellite imagery, variations in thickness require the analysis of direct in- situ observations. This project is an effort to analyze selected sea ice draft profiles obtained with an upward looking sonar by U.S. submarines while crossing the Arctic Ocean. These data have been obtained routinely since 1975, but have not yet been subjected to a rigorous examination, nor have they been related to other in situ and remotely sensed environmental data. The proposed statistical techniques are expected to be sufficiently precise to reveal interannual variations in the arctic ice thickness on the decadal time scale, which may be an early indicator of hemispheric climate change.
