摘要
利用常规气象资料、自动站资料、NCEP再分析资料,对江淮流域4次长生命史的飑线的形成原因、发展演变过程进行天气学分析。结果表明:飑线的发生需要强位势不稳定层结,且高层有冷空气的不断补充是飑线长生命史维持的主要原因之一;江苏东部的沿海地形为其发生发展提供了良好的水汽输送条件;强的环境风垂直切变,中高空急流和高空辐散场能使飑线维持较长的生命史。4次过程从雷达反射率因子图中,均可分析出典型的弓形回波结构。成熟的弓形回波结构严谨,宽度很窄,前沿有阵风锋存在。垂直结构上,在弓形回波的前侧入流一侧,存在较大的回波反射率因子梯度,回波顶位于强反射率因子梯度区之上;伴随着飑线的发展,在多普勒雷达径向速度图上有中层径向辐合和低空大范围的大风速区;中气旋和MARC可作为预报灾害性大风的可靠判据。
Based on conventional observation data, automatic weather station data, NCEP（ 1 °x 1 ° ） reanalysis data and Doppler radar data, the causes of formation, development and evolution process of four long life squall line on Jianghuai River basin have been researched. The main conclusions are： long life squall line needed strong unstable stratification, and the supplement of high cold air was one of the basic maintenance reasons of it. Coastal terrain in Jiangsu provided the long life squall line with a good water vapor condition. Intensive conditions, such as strong environmental vertical wind shear, upper jet and upper air divergence, all could maintain long life squall. The squall lines are charactarized by typical bow echo on the radar screen. The structure of mature bow echo was rigorous, the width was narrow and in front of how echo, there was gust front. The vertical structure of the bow echo showed that on the in flow side of how echo there was high reflectivity gradient, and the echo top was located above the strong reflectivity gradient zone. Squall line on Doppler radar radial velocity images was associated with the de velopment of the wide low speed area and MARC at midlevel. The MARC and mesocyclones could be considered as earlywarning of disastrous winds on the ground.
出处
《气象科学》
CSCD
北大核心
2013年第5期577-583,共7页
Journal of the Meteorological Sciences
基金
公益性行业(气象)科研专项(GYHY201006004)
关键词
飑线
温度
湿度差动平流
弓形回波
Squall line
Different advection of temperature and humidity
Bow echo
