Multi-Satellite Observation of an Intense Dust Event over Southwestern China

摘要

This study presents the results of a large-scale examination into a dust event that took place over southwestern China, an area that has received relatively little attention in the literature. The sources, transport path, and vertical distribution, as well as formation process of an intense dust storm event that took place over the Sichuan Basin from March 9 to March 14, 2013, were investigated using combined multiple satellite observations and meteorological data. Widespread dust plumes appeared over the Taklimakan Desert, Gobi Desert, and Loess Plateau on March 9. Different from the usual dust storms, the dust plumes did not move downstream directly but settled over the Loess Plateau and Sichuan Basin for several days. Persistent southwestern winds prevailed over eastern China during this period, and could prevent the dust storms from moving directly downstream. Our results suggest that the dust plumes over southwestern China mainly originated from the Gobi Desert. Despite extensive dust plumes over all the Sichuan Basin, PM10 increased sharply to more than 1200 μg/m3 in the western part of the basin, with only a slight increase in the eastern part. When there was a sharp increase in coarse particles in Chengdu on March 11 and 14, northeasterly winds appeared over northern China. The elevated dust can be blown to the eastern slope of the Tibetan Plateau and deposited in the western Sichuan Basin. However, such intense dust events are not common in southwestern China. In addition, floating dust may not be observed near the surface, but can have an important impact on regional aerosol loading and properties.