Dynamics of Climate Extremes in Northern Eurasia in the Late 20th Century

摘要

Changes in climatic parameters and in temperature and precipitation extremes in northern Eurasia in the late 20th century are analyzed.A spatial distribution of temperature and precipitation anomalies and of a set of indices of climate extremes is presented.Changes in climate extremes show a tendency toward a milder climate,mainly in winter.At the same time,the frost-free period has substantially decreased in the eastern,northern,and central parts of European Russia.In some regions during summer,there is an increase in the frequency of extreme events such as heavy rains,droughts,and sharp cooling.It is shown that the geographic pattern of present-day climate anomalies is linked to variations in the large-scale atmospheric circulation.The main mechanism of the current warming in northern Eurasia is a winter intensification of zonal flow linked to the increased frequency of positive anomalies of the North Atlantic Oscillation index.