摘要
利用三维雷暴云动力-电耦合数值模式,通过对青藏高原地区2003年8月13日一次雷暴过程进行模拟,分析了高原雷暴的电荷结构特征并从微物理角度讨论了其主要形成原因。结果表明,高原雷暴以三极性结构为主,在消散阶段电荷结构转变为偶极性,结构整体电荷密度较小,主正电荷区与主负电荷区深厚,下部次正电荷区范围较大,持续时间较长。其中三极性结构主要是由于云内冰相粒子通过非感应起电机制作用形成;后期偶极性构是由霰粒子下落固态降水的增强导致。云内暖云区厚度较小,混合相区域内有效液态水含量较高,对流层顶较低,导致冰晶、雪所在的高度更低,与霰、雹这样的大粒子重合的区域更大,形成了下部范围较大持续时间较长的正电荷区。
To further recognize the particularity of thunderstorm over Qinghai-Tibetan Plateau（ QTP）,this paper has analyzed the primary attribution of charge distribution,and also predicted the microphysics and electrification occurring on 13 August 2003 in QTP,using a three-dimensional dynamics-electrification coupled model. The charging parameterization included both the graupel/hail-cloud/ice inductive charging mechanism and the graupel/hail-ice non-inductive charging mechanism. The charging processes betw een other large and small particles are small,so they were ignored in this study. The results indicated that the characteristics of thunderstorms in QTP are unique. The life period of the thouderstorm is short,and the positive cloud-to-ground flashes occur frequently. The updraft and dow ndraft are weaker,and solid precipitation is more than liquid precipitation. Cloud top of thunderstorms are low and warm cloud area is small. Meanw hile,the height of solid small particles（ ice crystals,snow） is low. The solid large particles（ gravel,hail） distributed widely and mainly grounded. The thunderstorms in QTP displays a vertical tripole charge structure,then transforms into dipole distribution during dissipate stage. total charge density shrinks,while the peaks of charge center is higher. The main positive charge center is located at 7 - 9 km（-40 --30 ℃）,and the main negative charge center is located at 4 - 7 km（-10 -0 ℃）. The lower positive charge center is located at 2 - 3. 5 km. And all the charge areas are uplifted with convection. The lower positive charge center occupies widely and it lasts a long time. The tripole distribution is referred to as non-inductive collisional separation betw een ice-phase microphysics. The main positive charge center is mainly formed by ice crystals,the main negative charge center and lower positive charge center are mainly formed by snow and graupel. The weakening of the non-inductive collisional charging mechanism betw een graupel and ice makes the lower positive charge center dissipate. The dipole one results from the precipitation of graupel particles. Because of the smaller warm cloud thickness,high effective liquid water content in mixed area,and lower the tropical tropopause,the overlap area of graupel and hail distribution is larger,so the lower positive charge is wide and last for a long time.
作者
郭凤霞
王曼霏
黄兆楚
李扬
穆奕君
廉纯皓
曾凡辉
GUO Fengxia;WANG Manfei;HUANG Zhaochu;LI Yang;MU Yijun;LIAN Chunhao;ZENG Fanhui(Key Laboratory of Meteorological Disaster,Ministry of Education（KLME）/Joint International Research Laboratory of Climate and Environment Change（ILCEC）/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters（CIC-FEMD）/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Adruinistration,Nanjing University of Information Science ＆Technology,Nanjing 210044,Jiangsu,China)
出处
《高原气象》
CSCD
北大核心
2018年第4期911-922,共12页
Plateau Meteorology
基金
国家重点研发计划资助(2017YFC1501503)
中国气象科学研究院基本科研业务费专项(2016Z002)
国家自然科学基金项目(91537209
91644224)
关键词
青藏高原
电荷结构
水凝物
Qinghai-Tibetan Plateau
charge structure
precipitation
