东北冷涡持续影响下郑州地区多日对流性天气特征分析

Analysis of the Convective Weather Characteristics in Zhengzhou under the Sustained NECV

利用常规观测资料、NCEP1°×1°再分析资料、加密自动站资料、FY2E红外云图及大气电场仪数据对2015年8月22~30日期间东北冷涡持续影响下郑州地区多日对流性天气特征进行分析结果表明:①东北冷涡长时间维持一方面与上游阻塞高压前部冷平流补充有关,另一方面与北上台风变性并入有关;②对流天气发生时,低层有一定的比湿,比湿锋区在一定程度上能触发对流。θ_(se)的密集带是高能高湿区,与对流性天气的落区有对应关系;③雷暴大风、冰雹天气不要求湿层深厚,但需要较高的CAPE,短时强降水需要一定厚度的湿层,CAPE并不一定很大;④中尺度福合线是5次対流性天气的触发机制,对流性天气起源于冷涡涡旋云系尾部因为该区域大气不稳定层结强。强降水与对流云边缘TBB梯度大值区对应⑤大气电场强度的变化和対流性天气的发生、维持及结束关系密切。

Based on conventional meteorological observation data, NCEP 6 hourly 1°×1° reanalysis data, ground automatic station data, FY-2E satellite images and the data of electric field alarm system, the convective weather characteristics under the continued NECV in Zhengzhou during 22 to 30 August 2015 were analyzed.Results showed that ①the maintenance of the NECV is not only related to the cold advection in front of the blocking high, but also related to northward typhoon.②The occurrence of convective weather need certain specific humidity at low layer, the humidity front can trigger convection to some extent.θse dense zone of the low layer is a high energy and high humidity region, which indicates the falling zone of the convective weather.③Thunderstorm gale and hail require thick wet layer and high CAPE, but short-time strong precipitation＇s CAPE is not necessarily large.④The mesoscale convergence line is the trigger mechanism of 5 times convective weather.Convective weather originated near the tail of the NECV cloud system, because atmospheric stratification is unstable in this area.Heavy convective precipitation is relative with the large gradient of TBB.⑤The change of atmospheric electric field intensity is closely related to the occurrence, maintenance and ending of convective weather.