Summertime Polar Front over the Russian Plains

摘要

The geographical position of the climatological polar front over the Russian plains in summer of 1948-1960, 1961-1990, and 1991-2007 is detailed. The location of the polar front is derived using the frequency of cyclonic centers and the module of horizontal temperature gradient computed from the reanalysis data of UEA CRU 2.5° × 2.5°. The East European and Asian branches of the polar front are reliably distinguished by all indicators. The geographical position of branches differs from S.P. Khromov's polar front map in July in details only. The present-day southward shift of the polar front over the East European Plain and the northward shift over the West Siberian Plain are revealed relative to the period of 1948-1990.