Analysis of Sea-Ice Areas Undetectable by the ASI Algorithm Based on Satellite Microwave Radiometry in the Arctic Ocean

In the period of intense ice melting, algorithms retrieving sea-ice concentration from satellite microwave radiometry (SMR) data may fail to detect vast regions of floating ice. Late-stage melting is characterized by an abundance of melt ponds on ice, resulting in considerable underestimation of sea-ice concentration. Also, during melting, ice concentration decreases and ice breccias disintegrate; therefore the size of ice floes decreases. In winter, at river mouths in the shelf seas, ice is formed with a heavy load of terrigenous sediments carried by the rivers. A dirty ice surface becomes visible in summer when snow cover melts off. SMR techniques fail to adequately determine dirty ice concentration. The paper considers the impact of ice melt, concentration, floe size, and dirtiness on the determination of sea ice extent in the Arctic in summer using the ARTIST Sea Ice (ASI) algorithm. Our study shows that the portion of ice cover left undetected by the SMR technique may range in different years 5.7 to 23.3% of the total Arctic sea ice extent.