2006年春季一次引起华北地区强沉降的沙尘暴过程的模拟研究

Numerical Simulation on a Dust Storm Producing Strong Deposition over North China in the Spring of 2006

2006年春季是我国北方地区2000年以来强沙尘暴过程最多的一年，浮尘和扬沙天气更是频繁发生。尽管，4月16-17日过程不是2006年春季最强的沙尘暴过程，但其在华北地区引起了严重的沉降，尤其对京津地区影响较大。这是一次由蒙古气旋引发的强沙尘暴过程。利用沙尘天气预测系统（IAPS2．0）对该次强沙尘暴过程进行了模拟试验，结果表明：该系统对沙尘天气的起沙和输送过程有较好的模拟能力，基本模拟出了这次强沙尘暴的发生和移动；沙尘受对流层中低层偏西风的作用输送到华北地区，并从山东半岛越过渤海湾向东输送；主要的沙尘源地是蒙古国南部和我国西北的内蒙古、新疆西部、甘肃、陕西北部，而起尘最大的地区在蒙古国和内蒙古的沙漠、戈壁地区；沉降最严重的地区是沙尘源区及其附近，可达到50g·m^-1，其他地区的总沉降量在10g·m^-2左右。

The dust-storm events occurred frequently in the spring of 2006, and the dust-in-suspension and blowing dust appeared almost every day over north part of China. The dust storm event of 16--17 April is not the most severe case during the spring of 2006, but severe deposition happened over North China, which affect Beijing, the capital of China. Therefore, the study of the case was concentrated on. The weather system causing dust storm was a Mongolia cyclone. On the base of weather system analysis, an integrated dust storm numerical modeling system （IAPS 2. 0） is employed to simulate the dust storm event. The results indicate the system is capable for predicting the dust emission rate from surface and dust concentration in the atmosphere of individual dust storm event. It is noticed that the dust emission and dust concentration in the air have been simulated successfully. Simulated dust concentration agrees very well with observational weather phenomena at surface and satellite images. Based on successful numerical simulations, the hourly simulation results were used to analyze the dust sources and deposition caused by the dust storrru The dust source places are in southern part of Mongolia, the middle and west part of Inner Mon-golian Autonomous Region, west part of Xinjiang Autonomous Region, Gansu, and north part of Shaanxi provinces. The most severe dust emission area is the desert and Gobi of Mongolia and Inner Mongolia Autonomous Region, but the deposition area is significantly wider than emission area, which almost affect the whole of north China. It is found the total deposition amount of this event is about 50g·m^-2 near the dust sources area and about 10 g·m^-2over the other area, respectively.