A Synoptic- and Remote Sensing-based Analysis of a Severe Dust Storm Event over Central Asia

A severe dust storm blanketing Central Asia on 3-4 November 2021 was investigated employing satellite remote-sensing, synoptic meteorological observations, reanalysis and HYSPLIT back-trajectories. The prevailing meteorological conditions showed an intensification of air subsidence over eastern Kazakhstan, featured in a typical omega-blocking system over the region and two troughs to its west and east axis, one day before the dust storm. The prevailing high-pressure system and temperature gradients over Kazakhstan modulated the dominant anticyclonic wind pattern generated from the south Balkhash basin toward the Caspian Sea, causing a huge dust storm that covered the southern half of Kazakhstan and large parts of Uzbekistan, Tajikistan and Turkmenistan. The dust storm originated in the steppes of southern Kazakhstan by violent downdraft winds. Initially it swept over eastern parts and then the whole of Uzbekistan, reaching the Caspian Sea in the west. Meteorological measurements and HYSPLIT back-trajectories at selected sites in Central Asia (Turkmenabat, Khujand and Tashkent) showed a remarkable dust impact that reduced temperature (by 2-4°C) and visibility to below 1 km at different periods, as the thick dust plume expanded in various directions. The extremely high PM concentrations (PM_(10) ＞ 10,000 µg m^(-3) in Tashkent) could endanger both human health and the environment, especially in a region suffering from high susceptibility to wind erosion and significant land degradation and desertification. Effective and immediate stabilising measures to control wind erosion in vulnerable areas of Central Asia are warranted.