Simulation on the spatio-temporal distribution and emission flux of dust aerosol over East Asia in 2000-2009

摘要

A regional climate model (RegCM3), coupled with an online dust module, is used to simulate the spatio-temporal distribution and emission flux of dust aerosol (smaller than 20 μm in diameter) over East Asia in the period from 2000 to 2009. The model performance is firstly evaluated against available observations. Simulation results show that the model can capture the characteristics of spatio-temporal distribution of dust aerosol very well over East Asia. There always exist two extremes of dust aerosol optical depth (AOD) and column burden (CB), one is in the Taklimakan Desert of Xinjiang Uygur Autonomous Region, China, and the other is in the Badain Jaran Desert of Inner Mongolian Autonomous Region, China. The maximum value of CB appears in spring, secondary maximum in winter and minimum in autumn. To the east of 110°E, dust is transported eastward from a maximum center at a height of 700 hPa over the East Asian continent. Dust emission sources are mainly located in the Taklimakan Desert, Badain Jaran Desert, North Qinghai-Tibetan Plateau and Southwest Mongolia. There is also an obvious seasonal variation of dust emission flux (EF). Annual mean dust EF is 1,015.34 mg/(m 2 ·d), of which 62.4% and 2.3% are re-deposited onto the East Asian continent through a dry and wet deposition process, respectively, and the remaining 35.3% is injected into the atmosphere or subject to long-range transport.