一次山东特大暴雨干侵入的作用  

Impacts of Dry Intrusion on a Heavy Rainstorm in Shandong Province

作　　者：韦英英 Wei Yingying(Quanzhou Meteorological Observatory, Shandong, Quanzhou 36200)

机构地区：[1]福建省泉州市气象台,泉州362000

出　　处：《气象科技》2018年第2期343-351,共9页Meteorological Science and Technology

摘　　要：以2009年7月17—18日一次山东特大暴雨为研究对象,利用NCEP/NCAR再分析资料、FY-2C卫星水汽资料及常规气象观测资料,通过数字化卫星水汽图像与大气动力场相结合的方式,揭示干侵入在本次暴雨过程中的特征及其对暴雨发生、发展的作用机制。结果表明,此次强降水过程是在高空槽和低层低涡切变的有利形势下产生的。暴雨过程与干侵入密切相关,干侵入在对流层中高层随高度向东倾斜,强降水出现在干侵入前沿湿度梯度最大值处的湿区一侧。卫星水汽图像干侵入暗区与对应着350hPa位涡高值区、干冷区。与干侵入相伴随的高位涡下传,使低层气旋性涡度加强,气旋发展。高层干冷空气下传有利于干层的形成和维持,干层的存在加强了暴雨过程的对流不稳定,对暴雨的加强和发展起重要作用。By employing the NCEP/NCAR reanalysis data,the FY-2 Csatellite water vapor images and the conventional meteorological data,in combination with the digitized satellite water vapor imagery and atmospheric dynamic field,the characteristics of dry intrusion and evolution and its impacts on the heavy rain during 17-18 July 2009 in Shandong Province are diagnosed.The results show that the upper-level trough and low-level wind shear cyclone were helpful to the heavy rain process.There existed a strong relationship between the evolution of the dry instruction and the heavy rain process,and the dry intrusion originated from the mid-high level tilted eastward with height;heavy rainfall occurred at the forefront of the dry intrusion on the wet side of the zone where humidity gradient was at its maximum.The dark zone at the satellite water vapor image had a better correspondence with the dynamic field corresponding with the distribution of the high potential vorticity,high potential vorticity,and low humidity at 350 hPa,and the downward cold air characterized with high potential vorticity and low humidity in the upper troposphere enhanced the development of the low-level cyclone.The dry cold air intrusion contributed to the formation and maintenance of the dry layer,which enhanced the convective instability during the development of the heavy rain process.

关 键 词：干侵入 位涡 暴雨 卫星水汽图像 

分 类 号：P458[天文地球—大气科学及气象学]