The Arctic Climate Warming and Extremely Cold Winters in North Eurasia during 1979-2017

Daily surface air temperature from ERA-Interim reanalysis is used to study the cold and warm anomalies observed in December-February 1979-2017 over three regions of North Eurasia. The air temperature anomalies were selected that exceeded the standard deviation in the absolute magnitude and persisted 7 days and longer. The anomalies were analyzed in terms of the frequency of occurrence, strength, persistence, extension and the integral index of severity. The reproducibility of the statistical characteristics of the anomalies was also considered using ensemble simulations with the MGO atmospheric general circulation model and prescribed boundary conditions from observation for the period 1979-2017. The observed and simulated trends of the anomaly characteristics over the whole period and their link to the surface air temperature anomalies in the Barents and Kara seas were also discussed. It was shown that the most significant cold anomalies have been observed in Western Siberia since the beginning of the 21st century, when positive winter temperature anomalies were recorded over the Barents and Kara seas.