林晓彤,师正,谭涌波,李璐滢,汪海潮. 2021. 不同水汽条件下气溶胶对雷暴云电过程影响的数值模拟研究[J]. 气象学报, (0):-, doi:10.11676/qxxb2021.030
不同水汽条件下气溶胶对雷暴云电过程影响的数值模拟研究
The role of water vapor in the effects of aerosol on electrification in thunderstorms——A numerical study
投稿时间:2020-09-26  修订日期:2021-02-20
DOI:10.11676/qxxb2021.030
中文关键词:  水汽含量,气溶胶,起电率,电荷结构,数值模拟
英文关键词:Water vapor  Aerosol, Charging rate, Charge structure, Numerical simulation
基金项目:(41805002),江苏省自然科学(BK20180808),江苏省高等学校自然科学研究项目(18KJB170010);南京信息工程大学人才启动项目(2016r042)
作者单位邮编
林晓彤 南京信息工程大学 210044
师正 南京信息工程大学 210044
谭涌波 南京信息工程大学 210044
李璐滢 南京信息工程大学 210044
汪海潮 南京信息工程大学 210044
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中文摘要:
      为全面了解水汽在气溶胶影响雷暴云电过程中的作用,本研究在已有的二维雷暴云起、放电模式基础上,通过改变相对湿度和气溶胶初始浓度进行敏感性数值模拟试验。结果表明:(1)随着气溶胶浓度的提升,雷暴云产生更多的小云滴,降水过程受到抑制。而当水汽含量增加时,云滴含量的增加速度更快,雨滴含量增加,缓解了降水变弱的趋势。(2)水汽含量较低时,随着气溶胶浓度的增加,更多小云滴被带入冻结层形成大量小冰晶粒子,从而霰粒含量增加,雷暴云起电过程增强。气溶胶浓度增加至一定的量级(3000 cm-3)时,冰晶尺度减小和雨滴含量的降低抑制了霰粒的生长,雷暴云起电过程受到削弱。感应起电和非感应起电过程随气溶胶浓度增加呈先增加后减少的趋势。水汽含量的增加促进了冰相粒子的增长,因此起电过程呈现持续增大的趋势,起电率在3000 cm-3气溶胶浓度下达到极值,电荷密度的增幅扩大。(3)水汽含量较低时,雷暴云难以发展成深厚的系统,气溶胶浓度变化对其影响不明显,电荷结构由三极性发展,在消散期演变为偶极性电荷结构;水汽含量较高时,雷暴云迅速发展成深厚的系统,随着气溶胶浓度的提高,在雷暴发展旺盛阶段电荷分布表现为多层复杂结构。因此,研究显示水汽含量在气溶胶浓度变化对雷暴云微物理、起电过程及电荷结构的作用中扮演重要角色。
英文摘要:
      Numerical simulations are carried out to investigate the role of water vapor in the effect of varying CCN (cloud condensation nuclei) on dynamic, microphysical, electrification and charge structure in thunderstorm clouds by changing the relative humidity and aerosol initial concentration. The results show that: (1) The thunderstorm cloud produced more small cloud droplets and the precipitation process was restrained as the aerosol concentration increases. When the water vapor increases, the increase of cloud drop content is faster, the content of raindrops increase, the trend of precipitation weakening is relieved. (2) When the water vapor is relatively low, more small cloud droplets are brought into the frozen layer to form abundant ice crystal particles as the aerosol concentration increases. And the content of graupel increases, so the electrification is enhanced. When the aerosol concentration increased to a certain level (3000 cm-3), the decrease of ice crystal size and raindrop content restrained the growth of graupel particles, and the electrification was restrained. Therefore, the trend of inductive electrification and non-inductive electrification increases first and then decreases as the aerosol concentration increases. The increase of water vapor promotes the growth of ice particles, and the electrification presents a continuous increasing trend, the charging rate reaches the maximum value at 3000 cm-3 aerosol concentration, and the amplification of charge density increases. (3) When the water vapor is relatively low, the thunderstorm cloud is difficult to develop into a deep system and the change of aerosol concentration hardly influenced it. The charge structure develops from tripolar to dipole charge structure in dissipation period. When the water vapor is relatively high, the thunderstorm cloud rapidly develops into a deep system. The charge distribution of thunderstorm is multi-layer complex structure as the aerosol concentration increases. Therefore, water vapor content plays an important role in the influence of aerosol concentration on the microphysics, electrification and charge structure of thunderstorm clouds.
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