新疆伊犁3.13强降水成因诊断分析
Diagnosis and Analysis of the Causes of the 3.13 Heavy Rainfall in Yili, Xinjiang

采用常规观测资料、NCEP逐6小时再分析资料(0.25？ × 0.25？)、风云2G卫星、伊宁新一代天气雷达回波等多源资料，综合诊断分析2023年3月13~14日伊犁暴雨过程(中高山区为雨转雪)。暴雨是在中高纬地区环流经向度较大的背景下，中亚低槽东移进入伊犁造成的。暴雨中心区850 hPa以下的水汽通量散度辐合中心高达？12 × 10^？5 g？cm^？2？hPa^？1？s^？1，为暴雨提供良好的水汽条件。暴雨期间边界层比湿大于6 g？kg^？1。暴雨中心区散度场、涡度场结构利于暴雨发生发展。暴雨期间低空急流强盛，急流核风速高达24 m？s^？1。冷平流利于中高山区雨转雪。FY-2G卫星TBB分析显示，暴雨中心区降水最强时段TBB ≤ ？40℃。多普勒雷达回波分析表明，暴雨期间组合反射率因子最大值41.2 dBZ，回波顶最大高度7 km；偏西低空急流强盛，利于强降水的发生发展。
The rainstorm process from 13th to 14th March 2023 in Yili (rain to snow in middle and high mountains) is synthetically diagnosed and analyzed based on the multi-source data such as conven-tional observation data, NCEP reanalysis data every 6 hours (0.25？ × 0.25？), FY-2G satellite and Yining new generation weather radar echo. The rainstorm is caused by the eastward movement of the Central Asia trough into Yili under the background of the high meridional circulation in the mid-high latitudes. The convergence center of water vapor flux divergence flux below 850 hPa in the central area of rainstorm is as high as ？12 × 10^？5 g？cm^？2？hPa^？1？s^？1, providing good water vapor conditions for rainstorm. The specific humidity of boundary layer during rainstorm is greater than 6 g？kg^？1. The structure of divergence field and vorticity field in the central area of rainstorm is con-ducive to the occurrence and development of rainstorm. The low-level jet is strong during the rain-storm, and the core wind speed of the jet is up to 24 m？s^？1. Cold advection is fluent in