一次沿天山暴雨过程的Tbb特征分析

Analysis of FY-2E TBB characteristic of a Heavy Rain process along Tianshan mountain

利用常规天气资料、新疆区域逐小时自动站、NCAR/NCEP的1°×1°再分析资料、FY-2E卫星相当黑体亮度温度(Tbb)网格资料等,对2011年7月1日-3日发生在北疆沿天山一带的局地暴雨天气从天气形势、对流指数、降水量与Tbb值关系等方面进行分析。结果表明:此次暴雨过程是乌拉尔山的北支槽南下配合西南暖湿气流输送充沛的水汽,在天山山区辐合造成的沿天山一带大范围暴雨天气;Tbb演变趋势与降水有很好的对应关系,降水主要发生于Tbb从低值区逐渐上升的初级阶段过程中。Tbb的演变趋势与降水趋势较为一致,但降水演变趋势较Tbb演变趋势有一定滞后性,这对短时临近预报有一定的帮助;Tbb低值区对应气压垂直速度的上升区,上升速度越大,Tbb值越低,说明Tbb资料对对流发展具有很好的指示意义;Tbb与Ki指数也有一定的对应关系,Tbb低值区(Tbb≦-30℃)范围较Ki指数高值区(Ki≧20)大。

The probability of rainstorm in Xinjiang is very little, so it is very difficult to predict it. In this paper, we use general synoptic data ,Auto Weather Station data, NCEP/NCAR 1°*1°reanalysis data, TBB Grid data from FY-2E geostationary satellite, with the weather situation, convectional index, Precipitation, TBB methods to analysis the rainstorm process happened in middle mountain from 1july to 3july 2011.The result shows that trough near Ural Mountain move south, southwest warm and wet airflow move northeast. There are convergent in Tianshan mountain, this lead to rainstorm. The evolvement?of TBB have a good parallelism??with precipitation. The precipitation occurred in a process which TBB from low to high. Ascend more acutely ,the precipitation is more strong, but when precipitation is occurred, The values of TBB are all below 0 ℃,TBB low area is corresponding?with pressure vertical velocity ascend area, the velocity is more fast ,the values of TBB are more low. This adequately illustrate that TBB data have a good indication signification for convection.TBB is also corresponding?with Ki index well, but the area of TBB low area is bigger than Ki index high area.