Современные тенденции изменения климата в бассейне реки Урал

Abstract

The study focuses on the transformation of main climate parameters (surface layer temperature and precipitation) in the Ural River basin at the current level. The study is relevant due to the location of a greater portion of the Ural River basin area within arid and water-deficient regions. Conclusions about the regional climate change in the studied basin are formulated on the basis of standard methods of statistical data analysis. Statistically significant linear trend coefficients illustrate a steady increase in the average annual air temperature in the Ural River basin. The trend component (R2) varies from 12 % (Kuvandyk) to 25–26 % (Aydyrlya, Belyaevka) and 36–42 % (Bredy, Uralsk, Orenburg, Atyrau). The largest contribution to the growth of average annual temperatures is made by the first three months of the calendar year (January-March) and the autumn months (October-November). The long-term precipitation amounts show no directional and statistically significant trends. In annual terms, a statistically significant increase in precipitation was found only in the western part of the Ural River basin (MS Ilek – 10 mm per 10 years; Sharlyk – 13 mm per10 years) and in adjacent areas (MS Buzuluk – 18 mm per 10 years). The key macro-regional trend in changing the precipitation regime is an increase in the proportion of the cold period precipitation. Within the studied basin, a steady trend of seasonal precipitation redistribution was recorded for all sectors of the catchment area, except for the lower reaches of the Ural River. In conclusion, the identified trends in the regional climate transformation indicate that these changes reflect changes in climatic conditions on a larger scale.