The Autumn-winter Response of Air Temperature to the Blocking Frequency in the Atlantic-Eurasian Sector

The changes in the response of air temperature to the variations in the instantaneous blocking frequency (IBF) ( ) between the periods 1979–1999 and 2000–2020 are studied. Blocking patterns, which are the spatial distributions of the coefficients of correlation between the IBF and the 1000 hPa temperature field, are used as the main characteristic. The blocking frequency is calculated in ten longitudinal sectors in the eastern direction from the west of the North Atlantic region to the eastern borders of Siberia and the Pacific Ocean. It is found that blocking patterns moved northward over the Atlantic region (November, December, and February), the Ural region and Siberia (November, January, and February) in 2000–2020. In addition, they were characterized by more pronounced areas of negative correlations over Eurasia and North America as compared to 1979–1999. Along with the pronounced correlation pattern of the Atlantic region, the patterns of the Ural region and Western Siberia (U-WS) proved to be the most significant. It is assumed that the IBF variability over the U-WS sector is an important indicator of the development of the most significant blocking processes over Eurasia in terms of the temperature regime anomalies. The influence of U-WS blockings was the least noticeable in 2000–2020 for December and in 1979–1999 for January, when the response of the temperature field to the blocking changes was similar to the response of the negative phase of the North Atlantic Oscillation.