ABSTRACT The PIs propose to examine the iceberg keel depth data taken on U.S. nuclear submarines under the Arctic pack ice for a record of temporal changes in ice thickness in the Arctic Ocean. These data provide the only means of looking at the historical record of ice thickness for the past 30 years and, as such, are an excellent recorder of the possible impact of global change on the Arctic. The results of this study are very important for understanding the persistence of the ice pack in the past with the possibility of predicting changes that could occur in the near future. The results will be a valuable test of predictions from climate models that indicate a magnified global warming effect in the Arctic that might result in the disappearance of the pack ice.
