Climatic characteristics of thaw in the territory of the Zhaiyk-Caspian water basin

Abstract

The climatic series of daily values ​​of average daily, minimum and maximum air temperatures from the beginning of instrumental observations until 2022 inclusive at 47 meteorological stations of the Zhaiyk-Caspian water basin is considered. The main characteristics of the distribution of air temperatures were calculated, the dates of the stable transition of the average daily air temperature through 0 °C, the average long-term dates of the beginning and end of the stable frost period in the territory under consideration were determined. A comparative assessment of the duration (number of days) of the stable frost period and the number of thaws with different durations for two periods (from the beginning of instrumental observations until 1973 and the modern period from 1974 to 2022 inclusive) was carried out. Most meteorological stations in the region under study recorded a decrease in the number of thaw events, which lasted up to 5 days. At the same time, the number of thaws lasting up to 10, 20 and 30 days increased significantly – from 2 to 6 times. In general, the frequency of thaws has increased, with the following months making a particularly noticeable contribution to this increase: November, February and March.