2002年3月20日沙尘暴天气的影响系统、起沙和输送的数值模拟

近年来,东亚地区严重沙尘暴的频发趋势,使沙尘暴成为当今社会广泛关注的重大生态和环境问题。本文利用一个以较高精度的地理信息数据为基础、具有清晰风蚀物理学概念的沙尘暴数值模式集成系统,对2002年3月19～22日主要沙尘暴事件的气象背景条件、起沙源、起沙率以及沙尘输送进行了模拟和较为细致的数值分析,并将结果与常规气象观测和卫星资料进行了对比。结果表明该模式对气象背景、沙尘源和沙尘输送的空间分布和时间演变有较好的模拟能力;起沙区域主要是蒙古国的巴彦洪戈尔省南部、南戈壁、东戈壁省,我国内蒙古阿拉善盟地区、锡林郭勒盟地区、甘肃北部和青海北部;起尘量最大的中心在内蒙古阿拉善盟地区的巴丹吉林沙漠和腾格里沙漠,平均达15mgm-2s-1;沙尘输送主要发生在对流层低层,在垂直运动较强的地方可以向上输送到500hPa。

Numerical Simulation of Synoptic Background, Sources, Emissions and Transport of Dust Storms during 20Mar, 2002 in China

In the past few years increase in frequency and intensity of dust storms were remarkable in east Asia. Dust storms has become one of the most outstanding ecological and environmental problems in north China, attacting much attention both domestically and internationally. In this paper, an integrated wind-erosion modeling system which couples a physically based wind-ersion scheme, the fifth Generation PSU/NCAR's mesoscale model(MM5) and a dust transport model with a high-resolution geographic information database were applied to analyze the dust storm of 19-22May, 2002. The results showed that the predicted area of dust storms is in good agreement with those of meteorological observation and satellite images. The results showed the coupled system is capable of simulating and predicting of spatial and temporal variations of dust emission sources and transport. The main area of dust emission sources are the south of Bajanchongor, the Omnogov and the Dornogov of Mongolia; Badain Jaran Desert; Tengger Desert; Ulan Buh Desert; Hexi Corridor; western to northern of QingHai province; Hunshandake sandy land;Horqin sandy land and Hebei province of China. Badain Jaran Desert and Tengger Desert are the main sources of dust emission, the averaged emission intensity is 15mg m -2 s -1 . It is also found that the dust could be transported vertically up to low-level troposphere generally.