Long-term Changes in the Characteristics of Growing Seasons in the Cis-Ural Region due to Climate Change

The peculiarities of the variations in the growing season characteristics in the Cis-Ural region over the 20th and early 21st centuries were studied. The information on average daily air temperature and precipitation at four weather stations was used. It was found that, against the background of a general increase in air temperature, there was a positive trend in the length of growing seasons due to the changes in the dates of spring warming and autumn cooling. Starting from 1936, three periods of changes in the growing season length were revealed, and the last one, which started in 1990, has been the longest. The sum of active temperatures, as well as total precipitation, insignificantly changed during the study period, which was confirmed by a small positive trend. The average daily temperature in growing seasons has almost not changed over 85 years. The comprehensive assessment of the weather conditions affecting the growth of grain crops was performed based on the analysis of the hydrothermal coefficient. The coefficient was used to estimate the frequency of droughts having different intensity. Some increase in the coefficient, as well as the positive trends in the amount of precipitation (especially in the Perm krai), indicate the improvement of the conditions for spring grain crop cultivation in this part of the Cis-Ural region.