Extreme Heat Waves and Extreme Summer Seasons in European Russia

Abstract

In the study, the large-scale heat waves manifested in one or more latitudinal zones of European Russia: south of 50° N, within 50°–60° N, and north of 60° N are considered. For each zone, the changes in the total seasonal duration of heat waves since the beginning of the 20th century and associated changes in the average seasonal temperature in the region are analyzed. For the periods 1901–1960 and 1961–2020, the total number of waves for different gradations of their duration has been obtained. A catalog of the largest (extreme) heat waves with a duration of three weeks or more with possible transitions between the zones has been compiled: there has been only 11 such waves since the beginning of the 20th century, including 6 waves after 2000. For these heat waves, their correspondence to the phases of the EA/WR, AMO, and PDO climate modes was analyzed. For three of them (1972, 2010, and 2016), the description of the geographical structure (temperature, mid-tropospheric circulation) and evolution according to the data on the circulation in the middle (including the correspondence to the episodes of anticyclonic quasistationary circulation (AQC)) and upper troposphere was performed. It has been found that at the stage when the tropospheric ridge over European Russia penetrates into high latitudes, additional blocking structures similar to the Rossby wave breaking appear, which seemingly prolong the persistence of the AQC region over European Russia.