STRUCTURE OF THE PHENOLOGICAL YEAR IN VOLYN REGION AND ITS VARIABILITY IN TIME AND SPACE

Abstract

The relevance of the research: regional, and particularly local, climate changes require further investigation, therefore studying phenoclimatic periodization of the region under conditions of intensive transformation of the global climate system is important and timely. Research subject is the chronological boundaries, duration of meteorological seasons in Volyn region and trends of their dynamics in time and space. The purpose of the study: to conduct chorological and chronological analysis of trends in changes of duration and temporal boundaries of meteorological seasons at weather stations in Volyn region from the beginning of the 21st century to 2023.Research methodology: the study is based on analysis of data from the Volyn Regional Center for Hydrometeorology (hereinafter – VRCHM) at six weather stations in Volyn region (Svitiaz, Liubeshiv, Kovel, Manevychi, Volodymyr, Lutsk) for 2001–2023 using methods of mathematical statistics, graphical, cartographic modeling. The results of the study: in the structure of the natural year, meteorological winter in Volyn constitutes 18% (averaging 67 days over the study period), summer – 31% (114 days), autumn and spring – approximately 25% each (92 days each).Winter is characterized by a tendency toward decreasing duration, while summer and spring show increasing trends.Autumn is the most stable season in terms of duration; four weather stations in the region show a very weakly expressed tendency toward reduction of its duration. In the west-to-east direction of the studied region, a decrease in spring duration and an increase in winter duration is observed. Autumn duration decreases from northwest to southeast of the region. Summer has the greatest duration at Svitiaz and Lutsk weather stations, decreasing toward the central part of the region. Such spatial features of meteorological season duration changes are explained by increasing climate continentality in the eastward direction and characteristics of underlying surface of the region (hypsometric elevation marks, water body areas, and areas with artificial coverage). Practical significance: the obtained results enable forecasting changes in the natural environment and related economic and social consequences, optimizing the functioning of housing and communal services, tourism activities, agriculture, forestry and water management.Conclusions: summer duration in Volyn region increases due to September, spring duration – due to positive air temperatures prevailing in January and February. Meteorological winter shortens as a result of warming during the cold period of the year. Autumn is the most stable season in terms of duration, with only its chronological boundaries changing. The prospect of further research lie in studying air temperature and humidity, precipitation patterns, and frequency of hazardous meteorological phenomena within meteorological seasons.