REGIONAL FEATURES OF CLIMATE CHANGE IN RIVNE AND POLTAVA REGIONS

The purpose of the research is to establish trends in climatic factors during 1974-2023 according to data from Rivne and Poltava weather stations and to compare them for 1974–1998 and 1999–2023. Meteorological databases (average annual, minimum, maximum temperature, annual precipitation, relative humidity) have been created for the cities of Rivne and Poltava, which are located in the forest and forest-steppe natural zones. When comparing climatic factors for 1974–1998 and 1999–2023 for the weather stations of the cities of Rivne and Poltava, it was found that for Poltava in the second period compared to the first, the average annual temperature increased by 1.7◦С (18.2%), for the city of Rivne the temperature increase was 1.6◦С (18.2%), The rates of increase in maximum temperature were recorded for the forest zone, where the maximum temperature increased by 2.0◦С (15.4%), for the forest-steppe zone, respectively, by 1.8◦С (13.1%). The minimum temperature for Rivne weather station increased in 1999-2023 compared to 1974-1998 by 0.8◦С (20.1%), while for Poltava the corresponding value was 1.7◦С (32.97%). That is, the increase in the minimum temperature was greater for the forest-steppe zone compared to the forest zone. A slight increase in annual precipitation was observed for both weather stations: for the Rivne weather station, this difference for the two periods was 17.7 mm (2.9%), and for the Poltava weather station – 13.9 mm (2.4%). Relative humidity, on the contrary, decreased in the second period for both weather stations: for Rivne - by 2.7% (3.5%), and for Poltava – by 2.3% (3.2%). Hydrothermal coefficients reflecting the hydrological conditions of the growing season were higher in Rivne than in Poltava and changed at a faster rate. Conclusions. When comparing climatic factors for 1974–1998 and 1999–2023 for the weather stations of Rivne and Poltava, it was found that the increase in average, maximum and minimum temperatures in the second period occurred in the range of 13-33%. In the second period, the increase in precipitation for the Rivne weather station fell mainly on the cold period (from December of the previous year to April of the current year) in contrast to the warm period (from May to September), the amount of precipitation decreased. During October-November, the amount of precipitation was almost the same for both periods. For the Poltava weather station, the increase in precipitation in the second period compared to the first period also occurred during the cold period (from November of the previous year to February of the current year), and during March-May (the exception is June) the opposite was observed - a decrease in precipitation. Amount precipitation also increased in the second period by 2.4-3.5%, in contrast to relative humidity, which decreased by 2.7–3.2% for both weather stations in the second period. This indicates that a slight increase in precipitation could not compensate for a significant increase in temperatures, which led to a decrease in relative humidity for the Rivne weather station. Hydrothermal coefficients (de Martonne coefficient and Selyaninov hydrothermal coefficient) were higher in Rivne than in Poltava and changed at a faster rate. There was increasing aridity during the growing season in both natural zones (forest and forest-steppe), with this process occurring more rapidly in the forest zone. There is an increase in aridity during the growing season in both natural zones (forest and forest-steppe), with this process occurring faster in the forest zone. Keywords: average annual, maximum and minimum temperatures, precipitation, relative humidity, hydrothermal indicators, Rivne weather station, Poltava weather.