贵阳机场一次冬季初雷强对流天气诊断分析

Diagnostic Analysis of a Winter First Thunderstorm Severe Convective Weather Event at Guiyang Airport

摘要: 为提高贵阳机场初雷及强对流天气的预报准确率，本文基于自观、雷达资料、欧洲中心ERA5再分析资料，对贵阳机场2024年1月1日的一次强对流天气成因进行分析。结果表明：500 hPa高空槽东移、850 hPa切变线是此次过程发生的天气背景。1日12时(世界时)贵阳站探空显示0℃层高度位于3379米，−20℃层高度位于6073米，有出现冰雹天气的潜势；1日12~15时贵阳机场上空850 hPa水汽条件好，贵州中南部整层可降水量较大；低层辐合、高层辐散，在垂直方向上形成抽吸作用；12时贵州中部垂直螺旋度绝对值较大，15时显著减小；12时贵阳机场850 hPa与500 hPa温差较大(20℃左右)，15时明显减小；12时贵阳机场上空低层强正涡度向上延伸至中层，预示着可能出现超级单体，15时中低层正涡度中心减小且下移，高层转为负涡度。

Abstract: To improve the forecast accuracy of initial thunderstorms and severe convective weather at Guiyang Airport, this study analyzes the causes of a severe convective weather event on January 1, 2024, based on automatic weather station data, radar data, and ERA5 reanalysis data from the European Centre. The results indicate that the eastward movement of the 500 hPa upper-level trough and the 850 hPa shear line provided the synoptic background for this event. The 12:00 UTC sounding at Guiyang Station showed the 0˚C level at 3379 meters and the −20˚C level at 6073 meters, suggesting potential hail conditions. From 12:00 to 15:00 UTC, favorable moisture conditions were observed at 850 hPa over Guiyang Airport, with high precipitable water throughout the atmospheric column in central and southern Guizhou. Low-level convergence and upper-level divergence created a vertical pumping effect. The absolute value of vertical helicity was significant in central Guizhou at 12:00 UTC but markedly decreased by 15:00 UTC. The temperature difference between 850 hPa and 500 hPa over Guiyang Airport was large (approximately 20˚C) at 12:00 UTC but significantly reduced by 15:00 UTC. At 12:00 UTC, strong low-level positive vorticity extended upward to the mid-levels over Guiyang Airport, indicating possible supercell development. By 15:00 UTC, the mid- to low-level positive vorticity center weakened and descended, while the upper levels transitioned to negative vorticity.