环境温湿层结对雷暴云空间电荷结构的影响  

The Effect of Environment Temperature and Humidity Stratification on Charge Structure in Thunderstorms

作　　者：郭凤霞[1] 张义军[1] 言穆弘[1] 董万胜[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《高原气象》2004年第5期678-683,共6页Plateau Meteorology

基　　金：国家杰出青年科学基金项目(40325013);中国科学院知识创新重大项目(KZCX1 SW 04)共同资助

摘　　要：非感应起电机制中决定雷暴云电荷结构的反转温度是液态水含量的函数,而液态水含量的空间分布又取决于环境初始场中气团平均相对湿度和对流不稳定性的配置情况。本文通过不断改变初始场中层平均相对湿度和对流有效位能(CAPE)的值,同时不稳定度因子K和SI也随之发生相应的改变,利用三维强风暴动力电耦合数值模式,来研究初始场温湿层结的不同配置对液态水含量进而对电荷结构的影响。结果表明,CAPE较小时,电荷结构与中层平均相对湿度的大小无关,均为准反极性,且起电活动较弱;CAPE很大时,较大和较小的中层平均相对湿度更易引起强的起电活动和偶极性电荷结构,当霰和冰晶共存的区域中心落在上升气流的外围时,会形成反极性电荷结构。当对流有效位能相同时,增加中层平均相对湿度,气层的不稳定性提高,更有利于对流的发展和偶极性电荷结构的形成,减小中层平均相对湿度,对流减弱,有利于准反极性电荷结构的形成。The reversal temperature affect charge structure in non-inductive electrification mechanism and it is a function of LWC (liquid water content). LWC depends on the arrangement of average relatively humidity and convective instability in initial field. In order to get different initial fields, we change the average relatively humidity of middle atmosphere and CAPE (convective available potential energy) and the instability factors of %K% and SI change together. Using 3D dynamics-electrification coupled model, the influence of temperature and humidity stratification on charge structure were researched. The results indicate that the electrical action is weak and charge structure is quasi reverted dipole and no relation to middle atmosphere average relation humidity when CAPE is small. When CAPE is big, bigger or smaller, the average humidity will induce strong electrical action and dipole charge structure. When the coexistent region between graupel and ice is out of updraft, it can form reverted dipole structure. On the same CAPE, increasing the middle average relative humidity will help convection development and form dipole structure and decreasing the average relative humidity will tend to form weak convection quasi reverted dipole structure.

关 键 词：三维数值模式 温湿层结 液态水含量 电荷结构 

分 类 号：P427.32[天文地球—大气科学及气象学]