哈密市三次暴雨过程水汽特征对比分析

利用常规观测、区域自动站逐小时降水、NCEP/NCAR和GDAS再分析等资料，对比分析了2018－2019年哈密市三次暴雨过程的环流背景、水汽输送、辐合（辐散）和水汽收支等特征。结果表明：三次暴雨过程均发生在巴尔喀什湖地区有低涡、蒙古地区有高压脊的环流背景下，当对流层高层南亚高压中心东移且东部中心强度增强、中亚西风槽前存在强西南急流，对流层中层欧洲高压脊偏强、低涡偏南、西太副高偏西偏北时，有利于暴雨落区偏南、降水强度强，反之暴雨落区偏北、降水偏弱。三次暴雨过程水汽源地、水汽输送路径及水汽贡献有所差异，水汽源地的多源性和源地水汽贡献量的多少会对哈密市降雨的强弱有一定的影响。对流层中低层蒙古的反气旋有利于暖湿空汽沿着河西走廊的偏东急流输送至暴雨区，有利于暴雨的增幅。三次过程不同边界水汽收支量有所差异，东边界的低层和西边界的中高层为水汽的主要输入边界。强降水区各边界水汽净流入的强度、维持时间以及水汽的辐合强度对强降水的发展和维持起关键作用。

Comparative Analysis of Water Vapor Characteristics of Three Rainstorm Process in Hami City

Using the conventional meteorological observations,hourly precipitation data of regional automatic stations, NCEP/NCAR and the GDAS reanalysis data, the circulation background, water vapor transport, convergence ( divergence ) and water vapor budget of three rainstorm processes in Hami City from 2018 to 2019 were comparative analyzed. The results show that the three rainstorm processes all occurred when a low vortex over the Balkhash Lake area, a high pressure ridge over the Mongolia area .When the position of the center of South Asian High in the upper troposphere was moved to the east and strength of the eastern center was enhanced, a strong southwest airflow in the front of the westerly trough in Central Asia,a high pressure ridge over Europe developed,the low vortex was northerly,the position of west Pacific subtropical high consistently was farther and north than ever,which is conducive to the rainstorm occurred in the south and increased the precipitation intensity ,on the contrary ,the rainstorm occurred in the north and the intensity of the rainstorm decreased. The Moisture Source, moisture delivery paths and moisture contribution of the three rainstorm processes were different. The multi-source of water vapor source and the amount of water vapor contribution of the sources had certain impact on the intensity of Hami rainfall. The Mongolian anticyclone was benefit for transporting the warm and humid water vapor along the Hexi Corridor to the rainstorm area. The water vapor budgets were different at four boundaries. The lower layer of the eastern boundary and the middle and upper layers of the western boundary were the main input of the water vapor. The intensity of water vapor inflow at each boundary of the rainstorm area, the maintenance time of water vapor inflow at each boundary of the rainstorm area and the intensity of water vapor convergence played the key roles in the development and maintenance of heavy rainfall.