东亚中纬度地区前期降水对中国北方春季强沙尘暴影响初探

A Preliminary Study On Relationship of Prior Precipitation in Mid-latitude East Asia and Spring Severe Dust Storms in Northern China

利用 1980～ 2 0 0 2年春季中国北方典型强沙尘暴序列和 1979～ 2 0 0 2年地面气象台站记录与卫星观测同化处理的格点降水资料 (CMAP) ,分析了中国北方春季强沙尘暴活动与其前期大尺度降水异常的关系。研究结果表明 ,中国北方春季 (3～ 5月 )强沙尘暴活动与东亚中纬度地区前期年 (前一年 6月至当年 5月 )平均降水有较高相关 ,其中蒙古西南部和东南部 ,中国新疆北部局部地区和内蒙古中部为高相关中心 ,是重要的沙尘源地。前 4个季度中前一年夏季 (6～ 8月 )降水与来年春季强沙尘暴活动负相关最高。另外 ,通过春季强沙尘暴活动与其前期土壤湿度和同期地表植被覆盖状况这两种和降水有关的下垫面因子的相关分析 ,发现前一年 6月至当年 5月的年平均土壤湿度及春季平均植被指数均与春季强沙尘暴序列有较高的负相关 ,而且高相关区的分布与降水场高相关区的分布大致相同。

Using the gridded precipitation data and time series of spring severe dust storms occurred in north China in 1980～2002, the relationship between both of them is examined in this paper. The main findings can be summarized as follows: (1) There is a considerable negative correlation between the spring severe dust storms of northern China and prior precipitation in mid-latitude areas of East Asia, especially in southwestern Mongolia, southeastern Mongolia, northern Xinjiang and central Inner Mongolia, where are important source regions of eolian dust. (2) The negative correlation of the spring severe dust storms series with the preceding summer precipitation anomaly is the most significant, compared with variations of precipitation in other seasons. (3)Also, there are strong negative correlations of the spring severe dust storms in northern China with prior seasonal or annual soil moisture and spring land vegetation index related to the precipitation, showing similar correlation patterns. This study will provide some useful information for long-term prediction of Chinese dust storms.