Home – Home – Jornals – Geography and Natural Resources 2023 number 1

Based on a statistical analysis of long-term observations, an assessment is made of the spatio-temporal distribution of frosts in the southern taiga of Western Siberia. In spite of the fact that a steady crossing of the average daily temperature of 5 °C during the last 15 years occurred 5-7 days earlier, on average, there still remains a high likelihood for the onset of frosts every year throughout the study territory. A spatial differentiation of the duration and intensity of frosts is observed; the average annual number of days with frosts from May to September changes from 7.5 in the south-west to 12 in the north-east and significantly varies from year to year. Over the last 35-year period the largest number of days with frosts was recorded in 1986, 1988, 1989, 1991, 1998, 2006 and 2010. The range of variability in the average long-term period without frosts is about 40 days. Frosts are a significant risk-forming factor for agriculture in the study area. To reduce risks in plant production, the probability that frosts occur in spring, summer and autumn is calculated for 10-day periods. It is noted that the greatest risks to the local system of plant production depend on late spring frosts. The probability of frosts in the third 10-day period of May is from 18 to 32 %, and the probability of frosts in the first 10-day period of June for the northwestern part exceeds 10 %. In recent decades, however, the number of events with the most dangerous late spring frosts with the temperature drops to -3 °C and below for most weather stations in the study area has been decreasing. In the region as a whole, a high probability of frosts in the following years cannot be excluded, especially for the spring-summer period.