Thermodynamic Characteristics of Atmospheric Drought and Circulation Conditions of its Formation in Western Uzbekistan

This study analyzes the thermodynamic and circulation conditions that contribute to the formation of atmospheric drought (AD) in Western Uzbekistan – Bukhara, Navoi, Khorezm regions, and the Republic of Karakalpakstan – between 1991 and 2024. The thermohygrometric coefficient of air dryness (THC) was applied as the primary atmospheric drought index to characterize the thermohygrometric conditions associated with drought events of varying intensity. The circulation patterns in Central Asia contributing to AD formations are related to tropical Turanian, moderate Turanian, and moderate southern air masses. Temporal trends in AD assessed using the non-parametric Mann-Kendall test revealed a general increase in the duration and severity of droughts. A comparative analysis between THC and the vapor pressure deficit (VPD) indicated that THC provides higher sensitivity to the seasonal and spatial variations in air dryness. The results contribute to the development of AD monitoring and early warning tools for arid regions of Central Asia.