We studied moisture content/aridity conditions in Buryatia (Russia) in summertime for the period of 1979–2019. Selyaninov’s hydrothermal coefficient (HTC) was used as the aridity criterion. The HTC was calculated on the basis of precipitation and 2 m temperature data from two datasets: meteorological stations and the ECMWF ERA5 project. A comparison of the HTC calculations for these two datasets was performed. The ERA5 data showed underestimated HTC values compared to the observations. The inconsistencies found are mainly related to the underestimation of precipitation in the ERA5 project compared to the observational data. The air temperature obtained from the two datasets agrees well for most stations, both in value and in long-term dynamics. It has been shown that at the stations in central and southern Buryatia, the increase in aridity (and decreased HTC) in 1979–2019 is mainly due to the increase in air temperature.

The bulletin of Irkutsk State University. Series «Earth Sciences»

The bulletin of Irkutsk State University. Series «Earth Sciences»

The article is devoted to the study of changes in duration and recurrence of heat waves in Irkutsk region, which are a significant component of global climate change process. The authors conducted an extensive analysis of observations on maximum air temperature during summer seasons from 1960 to 2023. It was found that the average number of thermal periods with temperatures above 25 °C has increased in many regions of Irkutsk area. A particularly noticeable increase occurred over the last decade, especially notable were years such as 2017, 2019, and 2021, marked by record indicators for both duration and intensity of heat waves. The most intense rise in cases of anomalously high temperatures occurs at meteorological stations Zhegalovo and Chervyanka. Three phases have been identified in the evolution of heat wave characteristics. The first phase covers the beginning of observation period (the 1960s–1970s), characterized by growth in the number of heat waves; the second phase (late 1970s – early 1980s) features their decline in activity; while the third phase (started in late 1980s) sees stable increases in mean temperature along with prolonged hot spells. Episodes of abnormal heat occur most frequently in July, accounting for 51 % of total days with this phenomenon throughout the summer season. The most intensive heat waves took place in 2019, 2017, and 2015, having the greatest impact on population and ecology due to their long continuous durations.