Numerical simulation of mesoscale circulations in the Tarim Basin associated with dust events

Abstract

The mesoscale atmospheric environment of a dust event in the Tarim Basin, Taklimakan Desert, one of the key sources of aeolian dust in Northeast Asia, is investigated. Dust events in the Taklimakan Desert, including blowing dust and suspended dust, have long-lasting attributes, whereas in the Gobi Desert, dust events occur in phase with the passage of synoptic cyclones. Numerical simulations are conducted for a well-defined dust event on 12-15 April 2002. The Regional Climate Model of the Meteorological Research Institute (MRI-RCM) is employed. The MRI-RCM horizontal grid size is 20 km. The model reasonably well simulates time variations and spatial distributions of the surface wind field. Three types of mesoscale flow are revealed by the simulation. Sequential formation and/or coexistence of these flows can cause wind intensification and active dust emission from various areas across the basin. This gives a possible explanation for the long lasting dust events in the Tarim Basin. A closer examination shows that the development of these mesoscale circulations is closely related to the large-scale flow field behind the surface low-pressure system. © 2005, Meteorological Society of Japan.