A century-long tendency of change in surface air temperature on the territory of Ukraine

Abstract

Early historical meteorological observations of air surface temperature on 11 meteostations in Ukraine (since 1808) were analyzed. However, since a larger number of stations have time series of temperature starting in 1821—1825, for more reliable estimates of the linear trend, the period 1824—2021 was required. The trend is 0.78 °C per 100 years for this period. According to the analysis of meteorological data, the average annual surface air temperature on the territory of Ukraine in 1900—2021 was 8.6±0.9 °C. However, for the more recent period of 1991—2020, it increased to 9.5±0.9 °C. The temperature in Ukraine exhibited an increase of 1.31±0.42 °C per 100 years during 1900—2021. Over the last 30 years, a more pronounced increase in annual surface air temperature, by 0.79±0.08 °C per decade, was observed. Changes in the temperature regime exhibit spatio-temporal patterns. In most parts of Ukraine in 1900—2021, a temperature increase is within 1.5—2.0 °C per 100 years. Simultaneously, some parts of northern, northwestern, and eastern regions, as well as the Vinnytska and Zaporizhzhska oblasts, are characterized by more intense warming, reaching 2.0—2.5 °C per 100 years, in contrast to southwestern, southern regions, and the territories adjacent to the Ukrainian Carpathians, where the temperature rise is within 1.0—1.5 °C per 100 years. Temperature anomalies from 1900 to 2021 indicate the lowest annual averages occurred in 1933, 1956, 1976, 1985, and 1987, while the highest annual averages were observed in 2007, 2015, 2019, and 2020. Between 1900 and 2021, the average monthly air temperature in Ukraine substantially increased in colder months (from October to March), ranging from 0.7 to 2.0 °C per century. Simultaneously, warmer months (from April to September) saw an elevation ranging from 1.0 to 1.9 °C per century. In the 1991—2020 norm, an overall warming trend of 0.5—1.3 °C per decade was observed. Notably, January showed a slight decrease in the warming rate, with a trend value of –0.1 °C per decade. An indicator of the seasonality of climatic conditions is the amplitude of surface air temperature (A). In Ukraine, the average amplitude A was 12.7±1.1 °C from 1900 to 2021 and 12.5±0.8 °C from 1991 to 2020. Analysis of the temperature amplitude over the 20th century and the early 21st century revealed a general tendency of decreasing A values (the trend is –0.5 °C per 100 years), primarily due to warming in the colder months. However, from 1991 to 2020, the trend in A values was only –0.001 per decade, attributed to a significant temperature rise during the warmer months. Based on the analyses of the Johansson-Ringleb continentality indices in Ukraine, the indices’ values were determined to be 59.3±3.7 for the period spanning from 1900 to 2021, and 59.0±3.4 from 1991 to 2020. An overarching trend indicates a decrease by 0.4 % per 100 years. However, from 1991 to 2020, a contrasting pattern emerged, revealing an increase by 6.4 % per decade. The three scenarios of annual average surface temperature changes in Ukraine (SSP1-2.6, SSP2-4.5, and SSP3-7.0) relative to pre-industrial levels in the late 19th century, based on greenhouse emissions scenarios by 2100, are discussed.