新疆塔里木盆地西部一次强对流性天气的成因分析

Analysis on the Cause of a Severe Convective Weather in the West Tarim Basin-Cn

利用区域自动气象站常规资料、探空资料、NCEP/NCAR 1? ×1?再分析资料及新一代天气雷达资料,对2015年9月4日出现在新疆兵团阿拉尔市的一次冰雹天气过程的发生、发展机理进行分析。结果表明:1) 西西伯利亚低槽南部的分裂短波是造成此次新疆塔里木盆地西部局地冰雹天气的主要影响系统。2) 局地短时强降水的产生是在天气尺度背景和多个中小尺度系统共同作用的结果。高空短波槽的扰动与低层西南气流的相互作用促使中小尺度的生成,导致此次该区域局地强降水、冰雹的发生。3) 逆风区可以作为强降水中心区域的一个判别指标;逆风区与强回波中心有较好的对应关系。4) 雷达反射率因子强中心和反射率因子梯度最大值区域对冰雹的落区预报有很好的指示作用,当】50 dBZ的强回波中心达8~9 km,回波顶高达到10 km左右时,已形成明显的冰雹云结构。

The occurrence and development mechanism of the hail weather process that occurred in Alar City, Xinjiang Production and Construction Corps on September 4th, 2015 were analyzed based on the routine data, sounding data, NCEP/NCAR 1? ×1? reanalysis data and new-generation weather radar data from the regional automatic weather station. The following results show: 1) The split shortwaves from the southern West Siberian Cold Trough were the primary contributing factors to the production of the local hail weather in western Tarim Basin, Xinjiang. 2) The short-term local heavy precipitation was caused by a combined action of the synoptic scale system with multiple small and mesoscale systems. The interaction between the disturbance of the upper-level shortwave and lower-level southwesterly flow, facilitated the generation of mesoscales and smaller, and resulted in local heavy precipitation and hailstorm in this region. 3) The headwind region might be used as an index for identification of the core area of heavy precipitation;there was a clear corresponding relationship between the headwine region and the strong echo center. (4) The strong center and maximum gradient area of the radar reflectivity factor are of indicative significance to the forecast of the hailing location. When a strong echo center >50 dBZ reached 8 - 9 km long and the echo height reached 10 km, an obvious hail cloud structure would have been formed.