中亚气旋引发的2次新疆强降水过程成因分析

利用常规观测、NCEP 1°×1°再分析资料,对由中亚气旋引发的2015年2月12—14日北疆暴雪天气过程(以下简称"201502过程")和2015年5月17—21日新疆暴雨天气过程(以下简称"201505过程")进行诊断分析,并用HYSPLIT模式模拟了这2次中亚气旋过程中的3条输送带.结果表明2次过程有共性也有差异...

Analysis of central-Asia cyclone with heavy rain in Xinjiang

Abstract Using conventional observations, hourly surface observations and FY satellite imagery, the features of central-Asia cyclone associated with intense precipitation in Xinjiang from 2014 to 2018 were studied and conceptual models were constructed. Results showed that 33 out of 115 precipitation episodes were due to central-Asia cyclones. Central-Asia cyclones mostly originate over northern Xinjiang and its surrounding regions, having the highest frequency in summer and lowest in winter. These cyclones move east or northeastwards quickly. They showed feature of baroclinic leafs or comma clouds over FY imagery. Although these cyclones usually have low intensity, their formation and development are accompanied with divergence in the upper-level troposphere. Central-Asia cyclones are shallow baroclinic lows. As the terrain rises towards the east, middle-low level vortices, shear lines and south or easterly moisture transport to the east of the vortex favors intense precipitation in Xinjiang. Warm and moist air near surface rising up to the upper-level troposphere forms the warm conveyor belt, while flow originated in the northeastern flank of the surface low going up to 850 or 700 hPa forms cold conveyor belt, and dry air from the upper-level troposphere subsiding down to the middle-low troposphere forms dry conveyor belt. There are close relationship between intense precipitation and the three conveyor belts.