贵州西部2020年深冬两次冰雹天气不同背景场分析

Analysis of Background Fields of Two Hail Weather in Late Weather of 2020 in Western Guizhou

摘要: 基于常规气象观测、MICAPS及EAR5 0.1˚ × 0.1˚等资料，对贵州西部2020年1月6日和1月24日两次冰雹天气过程的天气系统配置、水汽条件、热力不稳定及垂直风切变等环境场特征进行分析，找出冬季两次冰雹发生的物理机制。结果表明：两次冰雹过程均受500 hPa南支槽、700 hPa西南急流以及200 hPa急流等天气系统影响。“01.06”过程，贵州西部处于200 hPa急流轴入口的右后方，南支槽向东移出贵州，“01.24”过程，贵州西部处于200 hPa急流轴出口的左前方，南支槽在98˚E附近维持少动。“01.06”属于南支槽型气团性冰雹，“01.24”属于高架雷暴型冰雹。“01.24”冰雹过程的逆温层比“01.06”明显且深厚，但“01.06”冰雹过程中的大气不稳定能量比“01.24”更为凸显。两次冰雹天气过程中，“01.24”中0 km~6 km垂直风切变比“01.06”偏大，且其垂直风切变的变化与锋面移动有明显的关系，冰雹落区与垂直风切变大值区的位置有较好的对应关系，冰雹直径大小与大气中的水汽、大气层结稳定度有密切的关系，与垂直风切变的关系不如春夏季冰雹明显。

Abstract: Based on the conventional meteorological observation, MICAPS and EAR5 0.1˚ × 0.1˚ data, the characteristics of environmental fields such as weather system configuration, water vapor condition, thermal instability and vertical wind shear of two hailstorms happened in western Guizhou on January 6 and January 24, 2020 were analyzed to find out the physical mechanism of the occurrence of two hailstorms in winter. The results showed that the two hail processes were both affected by the weather systems such as 500 hPa south branch trough, 700 hPa southwest jet and 200 hPa jet. In the process of “01.06”, the west of Guizhou was in the right rear of the entrance of 200hPa jet axis, and the south branch moved eastward out of Guizhou. In the process of “01.24”, the west of Guizhou was in the left front of the exit of 200 hPa jet axis, and the south branch maintained less movement near 98˚E. “01.06” was a air mass type hail in the south branch trough, and “01.24” was an elevated thunderstorm type hail with cold air moving south and forming a cold mat. The inversion layer during the hail process of “01.24” was more obvious and deeper than that of “01.06”, but the atmospheric unstable energy during the hail process of “01.06” was more prominent than that of “01.24”. 0 km~6 km vertical wind shear in “01.24” is higher than “01.06”, and the change of the vertical wind shear has obvious relationship with frontal moving, the hail drop zone has a good corresponding relation with the position of vertical wind shear greater values, the hail diameter size has a close relationship with the moisture and the stability of atmosphere, however, the relationship with vertical wind shear is not as obvious as hail in spring and summer.