雷暴云首次放电前两种非感应起电参数化方案的比较  

Comparison of Two Parameterization Schemes for Noninductive Mechanism before the First Discharge in a Simulated Single Cell Storm

作　　者：郭凤霞[1,2] 张义军[3] 言穆弘[2] 

机构地区：[1]南京信息工程大学大气物理学院 气象灾害省部共建教育部重点实验室,南京210044 [2]中国科学院寒区旱区环境与工程研究所西部气候环境与灾害实验室,兰州730000 [3]中国气象科学研究院雷电物理与防护工程实验室,北京100081

出　　处：《大气科学》2010年第2期361-373,共13页Chinese Journal of Atmospheric Sciences

基　　金：公益性行业科研专项GYHY200806014;国家自然科学基金项目资助项目40605002;南京信息工程大学校基金2008031

摘　　要：在三维强风暴动力-电耦合数值模式中分别引入两种基于不同实验室结果的非感应起电参数化方案S91和SP98,对比分析了一次雷暴单体首次放电前,利用两种方案模拟得到的非感应电荷转移区域、极性、量级和电荷结构的演变特征,及其与有效液态水、温度、粒子分布和对流之间的关系。结果表明,S91中,起电区域逐渐由高温、高有效液水区向低温、低有效液水区转移。电荷转移量快速增加,且由以正极性为主过渡为以负极性为主。电荷结构由偶极性转变到三极性。SP98中,淞附增长率的大值区范围较大,霰以携带正电荷占绝对优势,易形成反极性的电荷结构,但有进一步转变为三极性的趋势。两种方案的共同点表现为:电荷层较高,位于对流区上部及雷暴移动方向前侧出流区;正电荷转移多发生在高有效液态水(或淞附增长率)和高温区,负电荷转移都发生在低有效液态水(或淞附增长率)和低温区;转移电荷的正中心均位于霰的累积区中心,负中心易出现在冰晶和霰共存区的中心。A three-dimensional dynamic-electrification coupled model is used to investigate noninductive electrification before the first discharge in a single cell of thunderstorm.Two laboratory-based parameterizations of noninductive graupel-ice charge separation,S91 and SP98,are compared.The evolution characteristics of noninductive charge separation regions,polarity,magnitude,structure and their relationships with effective liquid water content,environment temperature,hydrometeor distribution,and convection are analyzed in this paper.The model results suggest that,in S91 scheme,charge separation initially occurs in the region with high values of temperature and effective liquid water content,and then moves to the region with low values.The charge separation rate quickly increases.Its domain polarity changes from positive to negative.The charge structure switchs from positive dipole to tripole.In SP98 scheme,graupel easily carries positive charges,owing to its large range of big rime accretion rate.It is likely to produce an inverted-polarity charge structure,but going with time,it tends to present tripole.There are some common characteristics between the two schemes before the first discharge.Firstly,the charge region altitudes are high and nearly located in the upper part of updraft and the outflow region in the front of storm moving direction.Secondly,positive charge separation primarily occurs in the region with high values of effective water content（or rime accretion rate）and temperature,however,negative in the region with low values.Thirdly,the positive and negative charging centers are almost consistent during the evolution,respectively.The positive corresponds with the graupel number concentration center,while the negative easily occurs in the coexisting region center of ice and graupel.

关 键 词：雷暴云 数值模拟 非感应起电机制 

分 类 号：P427[天文地球—大气科学及气象学]