Study on typical dust aerosol transport processes and radiative effects in Central Asia using EOF decomposition

Dust aerosols in Central Asia significantly shape global climate change through their optical, microphysical, and radiative properties. This study uses MERRA-2 and CALIPSO data from 2007 to 2021 to examine the dust budget and vertical diffusion patterns via empirical orthogonal function (EOF) analysis. The clear sky aerosol radiative forcing (ADRF) of dust aerosol is also investigated to evaluate the performance of climate models. The research results indicate that specific dust source regions correspond to the primary pattern of dust activity in Central Asia. The spatial distribution of dust exhibits an east–west oscillation, while the temporal distribution displays an alternating annual cycle. The major sources of dust emissions include the southern margin of the Tarim Basin in Xinjiang, the Gobi Desert, and areas surrounding the Aral Sea. Dust activity over the Tarim Basin peaks in spring, with concentrations typically observed at altitudes between 2 and 6 km. In autumn, as dust spreads, its altitude gradually increases, reaching a maximum of 5–8 km. Under clear-sky conditions, dust aerosol direct radiative forcing rises steadily in spring but decreases through fall and winter, with a minimum of +0.90 W/m² in December. Under clear-sky conditions, seasonal net shortwave forcing at the top of the atmosphere and surface shows negative values, indicating a net cooling effect. In contrast, atmospheric shortwave ADRF and surface longwave ADRF exhibit positive values. These peak in spring at +6.10 W/m² and +1.40 W/m², respectively, and minimize in winter at +1.20 W/m² and +0.33 W/m².