Seasonal Mechanism of sea ice melting in the Arctic Seas

Monthly ERA interim reanalysis data are analyzed via CSEOF analysis to understand the mechanism of sea ice melting in the Arctic Ocean and the Arctic amplification. While sea ice melting is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains to be thin in winter only in the Barents and Kara (BK) Seas. Excessive turbulent heat flux through sea surface exposed to air due to sea ice melting warms the atmospheric column. Warmer air increases downward longwave radiation, which ultimately increases surface air temperature and leads to further sea ice melting. This mechanism is not clearly observed in the Laptev, East Siberian, Chukchi, and Beaufort (LECB) Seas, since sea ice refreezes in late fall (November) before excessive turbulent heat flux is available for warming the atmospheric column in winter. Detailed seasonal heat budget is presented in order to understand specific differences between the BK and LECB regions. The positive feedback in the BK is estimated to accelerate at the rate of ~8% per year. Sea ice is expected to disappear in the BK by around 2025.