Quantifying Sea Ice Formation Rates In The Laptev Sea By Means Of ENVISAT SAR Scenes And Airborne Ice Thickness Measurements

Abstract

The Laptev Sea is considered as one of the most significant sites of net ice production in the Arctic Ocean. However, the few existing satellite and model-based studies on ice formation rates in the Laptev Sea show large differences in ice flux estimates. These discrepancies can be explained by the use of different sensor systems, models, observation periods and the lack of observational data. The latter gap may be filled by the so called electromagnetic (EM) Bird of the Sea Ice Group at the Alfred Wegener Institute. The Bird is an airborne system that utilizes the contrast of electrical conductivity between sea water and sea ice to determine the ice thickness along the flight path. Together with the EM-Bird ice thickness measurements, polynya area estimates obtained from ENVISAT SAR satellite images were used to quantify seasonal ice export and production rates in the Laptev Sea. The approach yielded a total ice volume of 81 km³ that originates from polynyas in the eastern Laptev Sea in 2008 (9 % of the net annual ice formation in the Laptev Sea). Our results imply that the contribution of polynyas to the net sea ice formation in the Laptev Sea is indeed higher than suggested by previous studies