The Effect of River Runoff on the Interannual Variability of Sea Ice Extent in the Kara and Laptev Seas

The ice cover variability of the Kara and Laptev seas in 1978–2022 and the effect of river runoff fluctuations on the ice processes in the seas are studied. A significant decrease in sea ice extent is detected for the analyzed seas. It is found that the influence of river runoff on the interannual variability of the sea ice extent increased in 2004–2022. An increase in the average annual sea ice extent was observed in the Kara Sea at a high water content of the Yenisei River and in the Laptev Sea at a high water content of the Lena River. The Ob River runoff affected the ice processes in the Kara Sea less than the Yenisei runoff. In the Kara Sea, there was a faster growth of sea ice in autumn and its delayed melting in spring during years with a high water content of the Yenisei. An increase in the Ob runoff caused a trend toward faster ice growth in autumn, but did not significantly affect ice cover melting in spring. The high water content of the Lena was associated both with the accelerated sea ice growth in the Laptev Sea in autumn and with its delayed melting in spring.