Трансформация максимальных осадков и стока Днестра в условиях изменения климата

Abstract

Global climate change causes the need to study the formation of water resources in certain areas. Here for the first time ever we studied both annual and intra-annual trends of changes in maximum precipitation and flow of the upper and middle Dniester tributaries. We expressed statis tical significance of the trends by the Mann-Kendall test and the trend index calculation. When considering annual maximum precipitation and flow during the entire observation period (1961-2010), there were statistically significant increases in the maximum discharge only of the upper Dniester observed, while in most of the left tributaries of the middle Dniester, the maxi mum discharge reduced. When considering the intra-annual changes, we divided the year into intra-annual intervals the boundaries of which were determined according to the changes in the conditions for formation of the maximum flow in the catchment area. The definition of trends within these intervals allowed revealing the tendencies of the decrease in maximum precipitation in the winter and spring seasons and an increase in the autumn period, especially in the mountainous part (right-bank) of the catch ment. When considering the intra-annual changes to maximum flow, we found a positive trend in the winter period and negative in the spring period. In the autumn period, the most significant in crease in the maximum discharge occurred in all the rivers of the Dniester Basin, caused by an in crease in the amount and intensity of precipitation during this season. The results of the research should be used in the water industry in Ukraine (operation of hy dropower facilities) and in the organization of flood prevention activities.

Глобальные изменения климата обуславливает необходимость изучения формирова- ние водных ресурсов определенных территорий. При рассмотрении годовых максимумов осадков и стока за весь период наблюдений (1961-2010 гг.) выявлены статистически значимые повышения максимальных расходов только верхней части Днестра, а на большинстве левых притоков среднего Днестра сни- жение максимальных расходов. Анализ внутригодовых изменений показал трансформации в распределении макси- мальных осадков и максимального стока. В осенний период происходил наиболее значимый рост максимальных расходов на всех реках бассейна. Результаты исследований необходимо использовать в водном хозяйстве Украины (режимов работы гидроэнергетических объектов) и для организации мероприятий по пре- дупреждению наводнений.