Meteorological Characteristics and Dust Distribution of the Tarim Basin Simulated by the Nesting RAMS/CFORS Dust Model

Abstract

A nested regional meteorology/dust-transport model was applied to an Asian region including the Taklimakan Desert. A three-grid system with a resolution of 81 km, 27 km and 9 km was designed and model calculation was conducted over the whole period of Apri1 2001 to examine the typical springtime meteorology and some dust episodes over the Taklimakan Desert region. The performance model was examined based on meteorological observation at WMO SYNOP station surrounding the Taklimakan Desert and ADEC special observation site at Qira. The model results reproduced complicated airflows within the Tarim Basin, strong down slope winds from the Tianshan Mountains when meteorological disturbances crosses over the Taklimakan region, and a strong easterly flow from the Hexi Corridor side. Composite analysis when the Tazhong site simulated an easterly wind was conducted and showed that the percentage of the occurrence of this condition was approximately 50% of the full simulation period. The scale of the easterly wind zone is 400 km in the Y direction, 1000 km in the X direction and 2-3 km vertically. Simulated high dust concentration shows a good correlation with this easterly wind zone. The model’s averaged dust concentration fields showed that the surface concentration ratio was approximately 0.6 between the eastern and western side of the Tarim Basin. However, the modeled ratio showed an opposite relation with the SYNOP visibility, thereby indicating that the current high wind type dust emission scheme may be insuflicient to simulate the suspended dust phenomena in the western part of the Tarim Basin.