一次冷涡飑线过程的天气特征分析

The Weather Characteristics of Squal Line in Cold Vortex

摘要: 本文利用自动站观测资料、多普勒雷达资料以及NCEP再分析资料，分析了一次东北冷涡形势下的发生于2012年7月21日北京的飑线过程，此次飑线过程造成了范围较大的雷雨大风等强对流天气。结果表明：在东北冷涡形势下，飑线生成时需要具备以下特征：1) 飑线发生前700 hPa、800 hPa高度场均有切变线出现，底层有辐合线出现。2) 飑线发生前低空存在较显著的负的垂直风切变，低空存在上升运动。3) 在飑线发生之前存在较明显的水汽通量辐合，而且水汽通量辐合区域与飑线发生发展经过的区域一致。4) 对飑线的雷达特征分析表明：飑线的成熟时期，飑线对应地区出现降水等天气现象。

Abstract: This paper uses the automatic station observation data, Doppler radar data and NCEP reanalysis data to analyze the process of the squall line occurring in Beijing on July 21, 2012 under the cold vortex situation in Northeast China. The squall line process caused a large range of thunderstorms and strong convective weather. The results show that under the cold vortex situation in Northeast China, the following characteristics are required for the formation of the squall line: 1) The 700 hPa and 800 hPa height fields before the squal line occurring have shear lines, and the bottom line has convergence lines. 2) There is a significant negative vertical wind shear at low altitude before the occurrence of the squall line, and there is an ascending motion at low altitude. 3) There is a significant convergence of water vapor flux before the occurrence of the squall line, and the water vapor flux convergence area is consistent with the area where the enthalpy line develops. 4) The analysis of the radar characteristics of the squall line shows that there is weather phenomenon such as precipitation in the corresponding area of the squall line.