伊犁一次极端暴雨成因分析

Analysis of the Causes of an Extreme Rainstorm in Yili

摘要: 采用常规观测资料、NCEP再分析资料、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2022年5月5~6日新疆伊犁河谷极端暴雨过程。暴雨是在中高纬地区多波动的环流背景下，中亚短波槽东移进入伊犁造成的。暴雨期间湿层深厚，5 g∙kg⁻¹的比湿伸至650 hPa以上。800 hPa以下的正涡度中心与暴雨高峰时段完全对应。暴雨中心区低层风场出现中β尺度涡旋。水汽收支计算表明，西边界输入的水汽起决定性作用。FY-2G卫星TBB分析显示，暴雨是由多个中尺度对流云团造成。雷达回波分析表明，暴雨期间低空急流较强，大气层结不稳定，上冷下暖，利于对流性降水的发生发展，垂直积分液态含水量峰值为7.5 kg∙m⁻²。

Abstract: An extreme rainstorm process from May 5 to 6, 2022 in Yili is synthetically diagnosed and analyzed based on the multi-source data such as conventional observation data, NCEP reanalysis data, 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 multiple wave-motion in the mid-high latitudes. The humid region is deep, and the specific humidity of 5 g∙kg⁻¹ extends above 650 hPa during the rainstorm. The positive vorticity center below 800 hPa is completely corresponding to the peak period of rainstorm. In the low-level wind field, there is a deep meso-β vortex in the central area of rainstorm. The calculation of water vapor balance shows that the water vapor input from the western boundary plays a decisive role. The analysis of FY-2G satellite TBB shows that the rainstorm is caused by multiple mesoscale convective cloud cluster. Doppler radar echo analysis shows that the low-level jet stream is strong, the atmospheric stratification is unstable, with upper cold and lower warm, which is conducive to the occurrence and development of convective precipitation, the peak value of vertically integrated Liquid is 7.5 kg∙m⁻² during the rainstorm.