Anticyclonic quasi-stationary circulation and its effect on air temperature anomalies and extremes over western Russia

Episodes of anticyclonic quasi-stationary circulation (AQC) are defined as sufficiently prolonged episodes during which the anticyclone overlaps a certain geographical domain. An algorithm for the identification of the AQC is described, and AQC numerical characteristics are introduced. A comparison with other blocking indices is presented. Analysis is presented for the geographic distribution of AQC frequencies in the Atlantic-European region, connections between air temperature anomalies (extremes) and different regimes, temporal variations of AQC characteristics, and accompanying changes in the frequency of temperature extremes in western regions of Russia in the last decades of the 20th century.