北京沙尘天气成因概率研究

Probability study on causes of dust events in Beijing

沙尘天气的产生受到多种因素交错作用的影响,如何客观量化各种因素对沙尘天气的影响已成为相关评价的难点,建立有效的量化方法是问题的关键。基于沙尘天气的群聚群发性特征,通过对沙尘天气发生的时空资料进行集合运算,以北京为例建立了一种量化沙尘天气不同成因概率的方法。在北京及其周边13个国家基准站相关资料(1971-2000年)的基础上,评价出不同因素对北京沙尘天气的影响情况为:(1)浑善达克沙地是北京沙尘暴天气的主要外地来源,毛乌素沙地对北京沙尘暴天气的影响概率几乎为零,前者对北京浮尘、扬沙天气的影响概率约为后者的2倍;(2)外地沙源对浮尘、沙尘暴、扬沙天气的影响概率分别约是北京本地影响的4.6,2.2和1.6倍;(3)北京本地沙源影响中,自然因素对扬沙和沙尘暴天气的影响概率约为人为因素影响的4倍,人为因素对浮尘天气的影响概率几乎为零。

The dust event occurs due to different influence of quantification is a difficulty in evaluating the dust extents various factors. How to make the influence objective It becomes key factor to give effective quantification method. Considering the temporal and spatial clustering features of dust events, a method to evaluate the dust events in Beijing is presented. By using the data of dust evtents in related stations, various influence probabilities of the dust events in Beijing are calculated. The result shows that the Otindag Desert area is the greatest external sand source to the dust events in Beijing, and the influence probability of Mu Us Desert area is nearly zero. The probability of influence of the former on the weather with floating dust and blown sand in Beijing is nearly 2 times of that of the latter. The influence probability of Beijing＇s floating dust from the external sand source is about 4.6 times of that from the local source, and dust storm is about 2.2 times, blown sand is 1.6 times. The influence probability of blown sand and sand storm due to natural factors is about 4 times of that due to the human factors in local source influence.