| 摘要 |
Based on the weather monitoring data, NCEP/NCAR reanalysis data and Doppler weather radar data, the circulation background, atmospheric stability and changing characteristics of radar echoes of a large-scale hail weather process in Ulanqab City on July 5, 2021 were analyzed. The results show that this hail weather process occurred in the summer afternoon of the hail-prone period in Ulanqab City, and was formed under the influence of upper trough and the circulation background of "two troughs and one ridge", which was conducive to the occurrence of strong convection weather. The low-level shear line provided the dynamic and water vapor conditions for the occurrence of the hail. In strong convection weather, water vapor was transported mainly from the Bay of Bengal, India and Nepal over the Himalayas. Before the occurrence of strong convection weather, water vapor transport increased significantly, and the low-level water vapor concentrated below 400 hPa, with obvious convergence and vertical transport. The characteristic parameters of radar echoes, such as combined reflectivity, vertically integrated liquid, and echo top height, increased significantly before and during the occurrence of hail, which had good indicative significance for the prediction and early warning of hail. |
