CHANGES IN THE HYDROTHERMAL COEFFICIENT AND IN THE FREQUENCY OF EXTREME HUMIDIFICATION CONDITIONS ON THE TERRITORY OF BELARUS DURING CLIMATE WARMING

Abstract

It is important to study the heat and moisture supply of the territory under climate warming conditions in Belarus since 1989, as well as changes in the occurrence frequency of extreme moisture conditions. The features of the spatial change in the averaged hydrothermal coefficient (HTC) for the period of climate warming (1989–2019) and the colder period preceding it (1960–1988) in the months of the growing season were revealed based on the maps constructed by interpolation. A decrease in the aridity of conditions in May and September in the southeast and east of the country, an increase in aridity in June and August (especially in the southern regions), an increase in the area with excessive moisture in July and its decrease in September were defined. 
 The article shows the features of changes in the frequency of droughts (HTC ≤ 0,7), less arid conditions (HTC = 0,71–1,0) and excessive moisture (HTC > 1,6) from May to September in 1989–2019, according to compared with the period 1960–1988. It was found that during the period of climate warming from May to September, there is a significant increase in the droughts frequency at meteorological stations in various regions of Belarus. A decrease in the number of years with drought in May and June is observed at several eastern and southern meteorological stations, in August – at the Zhitkovichi meteorological station, in September – at the Kostyukovichi meteorological station. The frequency of arid conditions in May, July and September decreases at many meteorological stations, and its changes are characterized by territorial heterogeneity. An increase in the number of years with less arid conditions is observed in most of Belarus in June and August. A significant increase in the frequency of excessive moisture was noted in July in most of the territory
 of Belarus, in May – in some regions. A decrease in the frequency of excessive moisture is observed at many meteorological
 stations in June and August; the number of years with excessive moisture increases only in the northern region. Spatial heterogeneity and less pronounced changes in the frequency of excessive moisture are noted in September.