2020年6月青海省果洛州连续两日大冰雹天气环境场对比分析

Comparative Analysis of Weather Environment Field of Two Consecutive Days of Heavy Hail in Guoluo in June 2020

对2020年6月青海省果洛州连续两日出现大冰雹天气环境场进行了对比分析。结果表明:(1)两日大冰雹均出现在副高西侧对流云团中,玛沁冰雹主要产生于西南风的风速辐合带中,班玛冰雹产生于高原切变线南端。(2)副高西侧偏南气流向降雹区输送暖湿气流,低层风速辐合、高原切变线流场给玛沁、班玛冰雹提供水汽汇聚和动力抬升条件。玛沁冰雹为低层暖平流强迫型,班玛冰雹为中低层斜压锋生型,玛沁冰雹CAPE值大于班玛冰雹CAPE值,两次冰雹均出现在CAPE值等值线密集带中。0℃层高度、-20℃层高度、0℃与-20℃层厚度均有利于冰雹产生,0~6 km垂直风切变均较大,利于对流云组织化发展,更加利于冰雹出现。(3)上升运动大值中心与0℃层或-20℃层高度层相对位置,对冰雹预报有较好参考价值。

This paper makes a comparative analysis on the weather environment field of two consecutive days of heavy hail in Guoluo in June 2020.The results show that:(1)The two-day hail occurred in the convective cloud cluster on the west side of the subtropical high.Maqin hail mainly occurred in the wind speed convergence zone of southwest wind,and Banma hail occurred in the southern end of the plateau shear line.(2)The southerly flow in the west of the subtropical high sends warm and humid air to the hail area.The convergence of low-level wind speed and the plateau shear line flow field provide the conditions for water vapor convergence and dynamic uplift for the hail in Maqin and Banma.Maqin hail is a low-level warm advection forcing type,and Banma hail is a low-level baroclinic frontogenesis type.The convective effective potential energy of Maqin hail is greater than that of Banma hail.Both hails occurred in the dense contour zone of convective effective potential energy.The height of 0℃layer,the height of-20℃layer and the thickness of 0℃and-20℃layer are conducive to the generation of hail.The vertical wind shear at 0~6 km is large,which is conducive to the development of convective cloud organization and the occurrence of hail.(3)The relative position between the high value center of ascending motion and the height layer of 0℃or-20℃has a good reference value for hail prediction.