Droughts in the High Continental Climate of Central Asia

Drought, one of the manifestations of emergencies, is a serious problem for Central Asia. Experts estimate that more than 70 per cent of the region's territory is considered vulnerable to natural disasters. Droughts are less frequent than floods, but affect more people. Over the past decade, 60 per cent of the population exposed to extreme weather events has been affected by drought. The most tangible impact of drought is on agriculture and food security in the region. Droughts are expected to become more frequent in Tajikistan, Turkmenistan and Uzbekistan due to projected temperature increases and longer periods of extreme heat and evaporation in areas with lower precipitation. In establishing drought monitoring and early warning systems in Central Asia and adapting drought prediction models, the monitoring of climate indicators and the availability of a rich and deep database of years is an important link. The purpose of this work is to monitor the probability of drought occurrence depending on the meteorological conditions of the Kafirnigan River basin in Tajikistan. The formation and dispersion zones of the Kafirnigan River differ significantly in their meteorological characteristics. The monitoring of droughts in the area of the river's formation and dispersion and their comparison with meteorological conditions allows establishing the existence of certain regularity between them. The results of such dependencies can form the basis for the development of drought early warning systems. A characteristic feature of the drought indices (SPI and SPEI) in the southern Tajik lowlands is their decreasing nature and the significant difference in the trends of change. Differences between SPEI-6 and SPI-6 are due to potential evapotranspiration (PET), which is determined by the difference between precipitation and evaporation. The similarity between SPEI and SPI in winter is reasonable because this is the period when PET tends to have the lowest ratio to precipitation, resulting in a functional approximation of SPEI to SPI. According to the same principles, the largest difference is observed in November, which covers the period from June to November, when PET is highest in relation to precipitation. It is found that for the period 1950-2023, monthly mean precipitation values are significantly lower and temperatures are higher than the climatic norm of the southern Tajik lowlands, leading to negative values of mean annual SPEI and SPI and favoring the occurrence of drought.

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