Simulated regional transport structures and budgets of dust aerosols during a typical springtime dust storm in the Tarim Basin, Northwest China.

Occupying an area of about 1,020,000 km2 with the sparse vegetation and the Taklimakan Desert(TD), The Tarim Basin (TB) is isolated by the surrounding mountains and plateaus, especially to the north of the Tibetan Plateau (TP) with a large drop in elevation. An intense dust storm occurring over TB, Northwest China from April 27 to May 1, 2015 was simulated by using the Weather Research and Forecasting model with chemistry (WRF-Chem v3.8.1). The sources of dust emissions were centered over the northeastern TB with the high dust emission flux reaching 24μgm−2 s−1 injected by strong near-surface northeasterly winds from basin mouth invading the TD. A large amount of dust aerosols accumulated in the windward northern slope of the TP. Dry deposition is the dominant removal process of dust aerosols from the atmosphere over the arid TB. The spatial distribution of dust dry deposition in the TB was similar to the columnar dust loading pattern during this dust storm event. With the impacts of the TB deep terrain structures on atmospheric circulation, the high column loading of dust aerosols was concentrated over the southeastern TB, where dust aerosols mainly accumulated at the lower troposphere below 3000 m. Once dust aerosols were lifted at a high elevation (>3500 m), they were exported from the TB driven by the westerlies in the free troposphere, and the zonal transport flux of dust aerosols (>3000 μgm−2 s−1) peaked at an elevation of approximately 4000 m along 41° N over the TB. The eastern border of TB was found to be the largest contributors to dust export from the TB. It was estimated for this intense dust storm that among the dust aerosols emitted from the dust emission sources over the TD, about 22.28% of dust aerosols were relatively inefficiently exported for the downwind dust regional transport from the TB compared to about 27.17% dust aerosols deposited on the basin surface, and a high fraction of about 50.54% dust aerosols suspending in the atmosphere over the TB, implying a significant implication of dust aerosols from the TD for climate and environment over the central Asian region. The Taklimakan Desert (TD) is located in the Tarim Basin (TB) isolated by the surrounding mountains and plateaus with the only an open in the northeastern TB edge. The effect of topography especially the Tibetan Plateau on dust aerosol distribution over the TB. Once dust aerosols were lifted at a high elevation (>3500 m), they were exported from the TB driven by the westerlies in the free troposphere, and the zonal transport flux of dust aerosols (>3000 μgm−2 s−1) peaked at an elevation of approximately 4000 m along 41° N over the TB. The eastern border of TB was found to be the largest contributor to dust export from the TB. The high fraction of 50.54% dust aerosols suspending in the atmosphere over the TB potentially exerted a large impact on regional changes of climate and environment over the TB for this dust storm event. Unlabelled Image • A strong effect of the Tibetan Plateau on the dust aerosol distribution over the Tarim Basin. • The zonal transport flux of dust aerosols peaked at an elevation of approximately 4000 m over the Tarim Basin. • The eastern border of Tarim Basin was found to be largest contributor to the downwind regional transport of dust aerosols. • A high fraction of about 50.54% dust aerosols suspending in the atmosphere over the Tarim Basin. [ABSTRACT FROM AUTHOR]