东北冷涡对江淮飑线生成的影响研究

Study of Squall Line Genesis with Northeast Cold Vortex

利用常规气象资料、自动站资料、卫星和雷达资料以及NCEP再分析资料，对近10年东北冷涡天气背景下强对流天气过程的物理机制和中尺度特征进行了分析，并重点分析了在东北冷涡背景下，2009年6月3、5和14日在黄淮和江淮地区分别产生飑线：许造成大范围雷雨大风、冰雹等强对流天气。结果表明，在东北冷涡发展阶段，即温压结构不对称、大气斜压性强时，冷涡的西、西南、南至东南部容易发生雷雨大风、冰雹等强对流天气。在东北冷涡形势下，飑线生成时具备以下特征：（1）存在明显的中尺度气旋式环流，850hPa、925hPa和地面有辐合线或干线存在；（2）静力不稳定，中低层温度直减率大；（3）风垂直切变强，风随高度强烈顺转，400—500hPa有西风急流存在，且与强对流天气的发生区域紧密相关；（4）伴随着飑线发展，在飑线后侧有显著升压，雷暴高压的强弱不仅指示了飑线发展的不同阶段，同时可作为地面大风预报的参考依据；（5）飑线的移动与对流回波的传播、出流边界和引导气流密切相关。

Using the conventional meteorological data, automatic station meteorological data, satellite data, radar data and NCEP reanalysis data, the physical mechanisms and mesoscale features of severe convective weather processes under the circulation background of northeast cold vortex in recent ten years were analyzed. The squall lines occurring under the situation of northeast cold vortex were studied mainly, which result in vast thunderstorm wind, hail and other severe convective weather in Huanghuai and Jianghuai region on 3, 5 and 14 June 2009. The results show that： During the development stage of northeast cold vortex, namely with the dissymmetrical structure of temperature pressure and strong atmospheric baroclinicity, the highest probability of thunderstorm wind, hail and other severe convective weather taking place at the west, southwest, south to southeast parts of cold vortex. Under the situation of northeast cold vortex, the squall lines occurring have some conditions as fol- lows ： （ 1 ） Obvious mesoscale cyclonic circulation 925 hPa and surface. （2） Hydrostatic instability exits, and there is convergence line or dry line on 850 hPa, The lapse rate of temperature in low and middle level is large. （3） Strong vertical wind shear. The wind strongly clockwise with height increasing; westerly jet exists on 400 - 500 hPa, which closely relates to the severe weather area. （4）, With the development of the squall line, there is large pressure-rise center behind it. The intensity of thunderstorm high not only indicates the different developing stage of the squall line, but also refers to disastrous wind fore, casting. （5） The moving path of the squall line closely relates to transfer of the convection echo, outflow border and the leading flow.