Near-surface air temperature in the Ukrainian Carpathians up to the middle of the XXI century by the EURO-CORDEX models

Abstract

The results of the assessment of future changes in the thermal regime of surface air in the Ukrainian Carpathians for the period up to 2050 are presented in this article. The assessment was performed on the basis of a set of climate indices (mean annual air temperature, number of frost days - FD, number of summer days - SU and number of tropical days - TR) calculated with high spatial resolution (0.05° × 0.05°) based on daily meteorological observations (1960-2020) and the results of 11 regional climate models of the EURO-CORDEX project (2021-2050). To obtain reliable, unbiased projections of air temperature, the model data were bias-corrected using linear scaling and variance scaling. Climate change was assessed based on the calculation of index increments for the period 2021-2050 relative to the period of the current climate 1991-2020. General trends towards an increase in surface air temperature in the region by the middle of the twenty-first century have been detected. Quantitative indicators of such changes: background increases are in the range of 0.35-0.41 °C (or, conditionally, 0.12-0.14 °С·decade-1) for the RCP4.5 scenario, and 0.53-0.56 °C (0.18-0.19 °С·decade-1) for the RCP8.5 scenario. The maximum increases in average annual temperature compared to the period of the current climate in 1991-2020 are 0.56/0.71 °C, respectively, and are confined to the highlands in the southeastern part of the region, i.e., higher warming rates are expected for the highlands. Changes in the threshold climate indices by the middle of the XXI century will have certain spatial differences: higher summer temperatures (SU, TR) are more likely for the northeastern macroslope and the southeastern part of the study area, and in the cold season (FD) of the year, under both scenarios, air temperatures will increase mainly in the northwestern and southwestern parts of the study region.