甘肃夏季特强沙尘暴分析  

Analysis of Summer Severe Sand-Dust Storms in Gansu Province

作　　者：王锡稳[1] 黄玉霞[1] 刘治国[1] 魏锋 张铁军[1] 

机构地区：[1]兰州中心气象台,兰州730020 [2]定西市气象局,定西743000

出　　处：《气象科技》2007年第5期681-686,I0004,共7页Meteorological Science and Technology

基　　金：国家自然科学基金项目"新一代天气雷达测量沙尘暴的能力和方法研究"(40475011);兰州中心气象台创新基金"夏季沙尘暴预报方法研究"共同资助

摘　　要：夏季沙尘暴的气候特征表明，夏季是甘肃省沙尘暴的次多发季节，主要集中在民勤、鼎新、金塔。通过对一次罕见的甘肃省夏季强沙尘暴天气分析发现：高空小槽、切变线、热低压是引发夏季沙尘暴的主要天气系统，而春季沙尘暴一般是大尺度天气系统造成的；夏季沙尘暴发生前期高空急流反映并不明显，急流风速的突然加大和沙尘暴几乎同时发生，这是夏季沙尘暴预报的难点之一；沙尘暴发生前8～12h的螺旋度场对沙尘暴预报有较好的指示意义，正值越大，沙尘暴越强，但当沙尘暴与强降水同时发生时，沙尘暴区螺旋度值明显小于强降水中心螺旋度值。Sand-dust storms in Gansu Province occurred most frequently in summer. The summer sand-dust storms concentrated around Minqin, INngxin and Jinta. The weather patterns for severe sand-dust storms in summer in Gansu Province are analyzed. The results show that upper troughs and shear lines and hot lows are main synoptic systems that result in summer sand-dust storms. Spring sand-dust storms are mostly induced by large-scale synoptic systems. Before the occurrence of summer sand-dust storms, the upper-level jet currents are not apparent. The sudden wind speed increase of the jet stream happens almost at the same time with a sand- dust storm, and that is one of difficulties in summer sand-dust storm prediction. The helicity field 8 to 12 hours before sand-dust storm occurring is a good indicator in forecasting sand-dust storms. The larger the helicity is, the severer the sand-dust storm is. But when a sand-dust storm and severe precipitation occur concurrently, the value of helicity in the sand-dust storm region is obviously less than that in the severe precipitation region.

关 键 词：夏季强沙尘暴 气候特征 螺旋度 

分 类 号：P445.4[天文地球—大气科学及气象学]