Циркуляционные факторы изменения климата на территории Иркутской области

Abstract

The paper presents the results of research conducted on large-scale and zonal atmospheric factors of climate variability over the territory of the Baikal region, which, according to Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet) is considered to be one of the regions characterized by highest rates of climate change. On the basis of trend, correlation, and spectrum analyses, investigation was made of high- and low-frequency components in multidecadal timescales of climatic indices dynamics, which determine and distinguish variability in pressure fields and geopotential at high latitudes in the Northern hemisphere, in the northern parts of the Atlantic and Pacific oceans throughout the time period of 1950–2017. In the dynamics of climate indices, cyclicity is manifested. It reflects the contribution of short-term and long-term variations, which are close in duration to the variability of continental and oceanic centers of atmospheric action in the Northern Hemisphere. Among climatic indices, the highest levels of correlation with changes in average monthly temperatures in the city of Irkutsk can be traced for the Scandinavian index. With an increase in surface pressure in the territory of Scandinavia, the contribution of advective heat and moisture fluxes from the Atlantic is weakened. The latter have a warming effect in the winter months on the territory of the Irkutsk region. Particular emphasis was put on searching for causes of increasingly arid climate in the Baikal region in summer months of 2000–2017, when the number of forest fires in the region rose dramatically.