Abstract:

This study investigates the temporal and spatial variability of sea ice area in the Chukchi Sea from 1991 to 2015 and the impact of Bering Strait Throughflow (BST) using satellite sea ice concentration data obtained from the National Sea and Ice Data Center (NSIDC). Results show that the sea ice area of the Chukchi Sea has decreased at a rate of 0.7 %·a^–1, and that sea ice cover has maintained a low stand since 2002. The heat flux of the BST, together with its circulation pattern in the Chukchi Sea, has an important influence on the temporal and spatial variation of Chukchi sea ice. Sea ice area is strongly correlated with the throughflow’s heat flux (R=–0.86). Both the correlation and variation rate are most significant in summer (May-August), indicating that the increase of heat flux can explain the reduction in sea ice area. The area where the sea ice concentration reduced most significantly on both seasonal and interannual scales is likewise attributable to the circulation of BST in the Chukchi Sea. Sea ice reduction is most significant in May to July above the three main pathways of the BST (Herald Canyon, Central Channel, Barrow Canyon). Supporting this causal mechanism, both the sea ice area and concentration have a lag response relative to the BST heat flux.

Key words: Chukchi Sea, sea ice area, temporal-spatial variability, Bering Strait throughflow, heat flux, circulation