一次蒙古气旋型强沙尘暴的数值模拟试验

Numerical Simulation on a Severe Sand-Dust Storm Process Caused by the Mongolia Cyclogonesis

利用沙尘数值预报模式对一次典型的蒙古气旋沙尘暴过程进行了数值模拟试验,结果表明:模式对沙尘区范围、强度及蒙古气旋不同发展阶段沙尘暴的强度、位置和演变进行了较成功的模拟。这次过程沙尘主要源于蒙古国南部及我国内蒙古中、西部荒漠化地区,沙尘以细中粉沙为主(d≤22μm)。模式模拟的沙尘暴日变化强于实况,其原因是模式没有考虑沙尘气溶胶辐射反馈机制。沙尘气溶胶的辐射强迫将削弱大气层结的日变化,从而有利于沙尘暴强度的维持。

Using the sand-dust storm numerical predict model, which coupling MM5 model, sand-dust raising and transporting models and GIS dataset, a severe sand-dust storm process occurred over the Northern China from 6 to 8 April 2001 has been done numerical simulation experiment. The results showed that the strength and evolution of Mongolia cyclone, the intensity, position and evolution of sanddust storm have been successfully simulated. The sand-dust source regions in this process were in south Mongolia and western Inner Mongolia of China. The small diameter dust（d≤220μm）was in a dominant position among the sand-dust particles contributing to the formation of sand-dust storm. The modeling di- urnal change of sand-dust storm strength, which acted as intensive in daytime while as weak at night, was greater than the observational one. The sand-dust radiation heating, which exists in real atmosphere but is not considered in the model, will minimize the diurnal change of atmospheric stratification and the intensity of sand-dust storm.