承德市一次由快速发展气旋诱发的大风天气分析  

Analysis of an Gale Process Caused by Rapid Developing Cyclone in Chengde City

作　　者：冯钰博 王宏 杨梅 高艳春 ENG Yubo;WANG Hong;YANG Mei;GAO Yanchun(Chengde Meteorological Bureau, Chengde 067000,China)

机构地区：[1]承德市气象局,河北承德067000

出　　处：《沙漠与绿洲气象》2019年第2期84-89,共6页Desert and Oasis Meteorology

摘　　要：利用常规观测资料和NCEP/NCAR(1°×1°)逐6 h再分析资料,对承德市2017年5月5—6日大风天气的环流形势和物理量进行分析,结果表明气旋的快速发展(气旋加深率0.84 B)导致锋生加强,引发气压和变压梯度加大是导致大风的直接原因。500 hPa高压脊东移迫使冷空气向南堆积,高空槽不断发展成为冷涡,温度平流为地面气旋的发展提供热力条件,高低层涡度平流的差异,也是地面气旋快速发展的重要原因;当1.5 PVU位涡面伸展至对流层低层时,局地位涡异常在气旋的发展过程中不可忽视;高空急流出口区发生质量调整,出口区左侧的辐散强度达10×10^(-5) s^(-1),使低层大气减压,有利于气旋发展。In this paper, we analyzed the atmospheric circulation features and physical mechanisms of gale weaher in Chengde City on May 5th to 6th 2017 by using conventional observational data and 6 hourly NCEP/NCAR reanalysis data(1°× 1°). The results show that pressure gradient and allobaric gradient caused by the rapid developement cyclone(deepening rate is 0.84 B), which caused frontogenesis strengthening, is the direct cause of gale weaher. The eastward movement of 500 hPa high pressure ridge forced the cold air to accumulate southward, high-altitude troughs continued to develop into cold eddies. Temperature advection provided thermal conditions for the development of cyclone. The difference between high and low layer vorticity advection is also an important reason for the rapid development of cyclone. Potential vorticity anomaly cannot be ignored in the development of cyclone while 1.5 PVU PV surface extends downwards to the lower troposphere. The divergence intensity on the left side of the upper jet outlet reaches 10×10^-5s^-1, which makes the lower atmosphere depressurized and conducive to the development of cyclone.

关 键 词：大风 气旋 温度平流 涡度平流 位涡 

分 类 号：P458.123[天文地球—大气科学及气象学]