Лëд и снег (Aug 2020)
Contribution of ice cover anomalies in the Barents and Kara seas to the circulation and temperature regimes of Northern Eurasia since the mid-1990s
Abstract
The intra-seasonal features of changes in the surface air temperature in winter of the North of Eurasia are considered for the purpose to find a relationship between them and the reduction of the ice cover area in the Barents and Kara seas and the atmospheric circulation modes in 1979–2013. Regression estimates and analysis of the regional distribution of the relationship between winter temperature, geopotential height anomalies of 500 hPa and an index of the Scandinavian mode (Scand) with the ice cover area anomalies show that its autumn reduction contributes significantly to the formation of Arctic invasions and abnormal cold weather conditions in Northern Eurasia at the beginning of winter – in December and January. In February, which, according to the received estimates, is associated by 90% with the trend towards decreasing of the average winter temperature in the North of Eurasia since the mid-1990s, the linear dependence of the Scand index and the temperature anomalies on the autumn reduction of ice cover is not found. The stable dependence of cold anomalies in the North of Eurasia at the beginning of winter on the strengthening of Scand allows us to consider it the main circulation mechanism that determines the intensity, scale and regional structure of these anomalies. In turn, the connection of the Scand anomalies with the ice cover area of the Barents and Kara seas in October indicates their potential predictability, which can be used to predict the circulation conditions for the formation of abnormal frosts in Siberia and the European part of Russia in December and January.
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