Spatiotemporal variability of atmospheric drought during the growing season in Poland: a multi-index analysis based on SPEI, VPD, and HTC (1980–2024)

Atmospheric drought constitutes one of the most significant manifestations of contemporary climate change in Central Europe, including Poland, where rising air temperatures and changes in precipitation patterns lead to increasing water deficits. The aim of this study was to analyze the temporal and spatial variability of atmospheric drought in Poland during the growing season over the period 1980–2024, with particular emphasis on the calendar periods of plant development. The analysis was based on gridded E-OBS data (Copernicus Climate Change Service). Three indices were applied to assess drought conditions: the Standardized Precipitation Evapotranspiration Index (SPEI), Vapor Pressure Deficit (VPD), and the Selyaninov hydrothermal coefficient (HTC). Trends were determined using Sen’s slope estimator and the Mann–Kendall test. The results indicate a clear intensification of atmospheric drought in Poland during the analyzed period. A statistically significant decrease in SPEI values (− 0.27/10 years) and a simultaneous increase in VPD (0.04 kPa/10 years) were observed across most of the country, indicating a deterioration of the atmospheric water balance and an increasing evaporative demand. The most pronounced changes were recorded in central and northern Poland. Seasonal analysis showed that the greatest deterioration in moisture conditions occurs during the mid-growing season (June–July), a period of high atmospheric water demand. Despite only a slight negative annual trend in HTC, decreases in its values during key growing-season periods indicate spatially heterogeneous changes in hydrothermal conditions. The obtained results indicate increasing atmospheric drought risk in Poland, with potential implications for agricultural vulnerability, and highlight the need for regionally differentiated adaptation strategies in water management and agricultural production.