摘要
利用NCEP再分析资料,对2014年5月25日湖南一次暴雨过程进行分析。结果表明:500h Pa高空槽、副热带高压、中低层切变线、地面冷锋是此次暴雨的主要影响系统。暴雨发生前,850h Pa比湿达16g·kg^(-1)、水汽通量达16~18g·cm^(-1)·h Pa^(-1)·s^(-1),700h Pa以下湖南有高达360K以上的假相当位温高能中心。暴雨发生时,垂直速度最强中心出现在400~600h Pa附近,达到-1.8^-2h Pa·s^(-1)。从850h Pa湿位涡水平分布来看,暴雨发生时,湿正压项等值线密集,且暴雨落区主要位于等值线密集带正负过渡地带附近;湿斜压项为负值区,且最小值为-0.4PVU,说明大气斜压性较强,对暴雨有一定的指示意义。从湿位涡垂直分布来看,中低层湿正压项正负值交界附近与强降水有较好的对应关系;中低层湿斜压项负值区指示大气斜压性较强、与正值区交汇处附近对强降水有一定的指示意义。
Based on NCEP reanalysis data, a heavy rain case occurred on May 25th 2014 in Hunan is analyzed. The results show that the main influencing system of this rainstorm are upper trough of 500hPa, subtropical high, low and middle shear line, ground cold front. Before the rainstorm, the specific humidity of 850hPa is 16gokg-1.The vapor flux is 16 -18 gocm-lohPa-los-1.Below the 700hPa, pseudo equivalent temperature is 360K.When the rainstorm occurs, the strongest center of the vertical velocity is 400 -600hPa, -1.8 --2hPaos-1. Form horizontal distribution of moist potential vorticity, when the rainstorm occurs, the contour of wet barotropic is dense. The rainstorm area is located near the transition zone of the isoline concentration zone. The wet baroclinic item is negative. The minimum value is - 0.4PVU. It shows that the atmospheric baroclinic is stronger. It has certain indication significance to rainstorm. From the vertical distribution of the moist potential vortieity, there is a good correspondence between heavy and low pressure positive and negative values at the junction of low and medium level and strong precipitation. The negative pressure region in the middle and lower layers indicates that the atmospheric pressure is stronger than that at the confluence of the positive region, which indicates the strong precipitation.
出处
《气象研究与应用》
2017年第3期53-60,I0004,共9页
Journal of Meteorological Research and Application
基金
湖南省气象局预报员专项(XQKJ16C008)
关键词
副热带高压
比湿
水汽通量
湿位涡
subtropical high
humidity
vapor flux
moist potential vorticity
作者简介
张俊利（1982-），女，工程师，硕士研究生，主要从事中短期天气预报研究工作，157655129@qq．com.
