Page 85 - 《高原气象》2023年第1期

1 期 邹迪可等：青藏高原雷暴云底部次正电荷区与暖云区厚度的关系 81

Relationship between Lower Positive Charge Center and Warm Cloud

Depth in Thunderstorms over Qinghai-Xizang Plateau

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）

Abstract： In order to make up for the limitation of thunderstorm processes observation， and to explain the rela‐
tionship between the large lower positive charge region （LPCC） and the warm cloud depth （WCD） of thunder‐
storms from the close relationship between dynamics， microphysics and electrification process over Tibet Pla‐
teau， sensitivity test groups are set in this paper. The sounding initial field of a thunderstorm process with obvi‐
ous 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 re‐
sults 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 precipi‐
tation process is less than the enhancement of strong updraft on warm cloud precipitation process. When the con‐
vective 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 condu‐
cive 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.
Key words： Qinghai-Xizang Plateau； lower positive charge center； warm cloud depth； numerical model