摘要
为了弥补青藏高原雷暴观测个例的不足,从动力、微物理和起电过程之间的密切联系来解释青藏高原雷暴云底部较大的次正电荷区(LPCC)和暖云区厚度(WCD)之间的关系,本文设置敏感性试验组,通过三种途径,改变了青藏高原那曲地区一次LPCC明显且对流较强的雷暴过程的探空初始场,得到10组具有不同WCD值的初始场算例,利用三维雷暴云动力-电耦合数值模式,模拟分析了WCD和LPCC之间的可能关系。结果表明,在青藏高原WCD并不是决定LPCC大小的唯一因素,明显的LPCC的形成需要较薄的WCD配合较强但不能太强的上升速度,即使WCD很薄,太强的上升气流也仅容易形成主正和主负电荷区非常强的一般型雷暴,太弱的上升气流,也仅能形成主正和主负电荷区很弱的一般型雷暴。雨滴的两个主要源项,即雨滴通过重力碰并收集云水和霰融化形成雨水,及霰的主要源项霰撞冻云水,这三个微物理过程的效率主要取决于对流强度。薄的WCD对暖云降水过程的抑制作用不及强的上升速度对暖云降水过程的增强作用。在对流强度变化不大的情况下,WCD主要影响着冰粒子的分布高度,WCD越薄,向0℃层以上输送的云滴尺寸越小,数目越多,越利于低层冰粒子的生长,LPCC和主负电荷区越明显;WCD越厚,越利于较高高度冰粒子的生长,LPCC趋于减弱,而主负和主正电荷区趋于明显。
In order to make up for the limitation of thunderstorm processes observation,and to explain the relationship between the large lower positive charge region(LPCC)and the warm cloud depth(WCD)of thunderstorms from the close relationship between dynamics,microphysics and electrification process over Tibet Plateau,sensitivity test groups are set in this paper.The sounding initial field of a thunderstorm process with obvious LPCC and strong convection in Naqu area of Qinghai-Xizang Plateau is changed by three ways,and 10 groups of initial field examples with different WCD are obtained.The possible relationship between WCD and LPCC is simulated and analyzed by using a three-dimensional dynamics-electrification coupled model.The results show that WCD is not the only factor determining the strength of LPCC in the Tibet Plateau.The obvious LPCC requires a thin WCD with strong but not too strong rising speed.Even if the WCD is very thin,too strong updraft is only easy to form a normal type thunderstorm with very strong main positive and middle negative charge areas,and too weak updraft is only form normal type thunderstorms with weak main positive and middle negative charge regions.The two main sources of raindrops,namely,raindrops collision and collection with cloud water and graupel melting to form rainwater,and the main source of graupel,namely,graupel riming with cloud water mainly depend on the convective intensity.The inhibition effect of thin WCD on warm cloud precipitation process is less than the enhancement of strong updraft on warm cloud precipitation process.When the convective intensity changes little,WCD mainly dominate the distribution height of ice particles.The thinner the WCD,the smaller the size and the more the number of cloud droplets is transported above 0℃.It is more conducive to the growth of low-level ice particles,and the more obvious LPCC and middle negative charge region.When WCD is thicker,it is more conducive to the growth of higher ice particles,and LPCC tends to weaken,while the middle negative and main positive charge regions tend to be obvious.
作者
邹迪可
郭凤霞
张志伟
初雨
鲁鲜
刘舟
吴泽怡
ZOU Dike;GUO Fengxia;ZHANG Zhiwei;CHU Yu;LU Xian;LIU Zhou;WU Zeyi(Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration/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),Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China)
出处
《高原气象》
CSCD
北大核心
2023年第1期68-81,共14页
Plateau Meteorology
基金
国家重点研发计划项目(2017YFC1501503)
国家自然科学基金项目(41975003,41875002)。
关键词
青藏高原
底部次正电荷区
暖云区厚度
数值模式
Qinghai-Xizang Plateau
lower positive charge center
warm cloud depth
numerical model
作者简介
邹迪可(1997-),男,山东威海人,硕士研究生,主要从事雷暴电学研究.E-mail:zdkkdz1242@163.com;通信作者:郭凤霞(1977-),女,甘肃平凉人,教授,主要从事雷暴电学研究.E-mail:guofx@nuist.edu.cn。
