大气冰核浓度对对流云降水过程影响的数值模拟  

Numerical Simulation of Influence of Atmospheric Ice Nucleus Concentration on Convective Cloud Precipitation Processes

作　　者：王梦旖 师正[1] 谭涌波[1] 刘俊[1] 于梦颖 郑天雪 WANG Mengyi;SHI Zheng;TAN Yongbo;LIU Jun;YU Mengying;ZHENG Tianxue(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 Administration,Nanjing University of Information Science&Technology,Nanjing 210044;Xinyang Meteorological Service,Henan,Xinyang 464000)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心/中国气象局气溶胶与云降水重点开放实验室,南京210044 [2]河南省信阳市气象局,信阳464000

出　　处：《气象科技》2020年第2期220-228,共9页Meteorological Science and Technology

基　　金：国家自然科学基金项目(41805002);江苏省自然科学基金资助项目(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基金项目(2016r042)资助。

摘　　要：在已有的三维对流云模式的基础上新植入了同质冻结和异质核化方案,结合一次山地雷暴个例,通过敏感性试验来探讨大气冰核浓度对对流云微物理过程和降水的影响。模拟结果表明:①冰核浓度的改变会对对流云的动力场及各水成物粒子产生明显作用。增加冰核浓度,冰相粒子的数浓度随之增加;同时,凝华过程中释放大量潜热导致云中上升气流增强。由于水汽含量一定,各水成物粒子"争夺"水汽,使得云滴、冰晶和霰的增长均受到抑制,难以成为较大尺寸的降水粒子。②冰核浓度的增加,"贝吉龙效应"导致云滴的尺度减小,削弱了云-雨转化过程。雨滴、云滴混合比的减小抑制了雨滴对云滴的收集。同时,小尺度的霰粒子削弱了霰融化为雨滴的物理过程,最终导致地面累积降雨量降低。Based on the existed three-dimensional convective cloud model,a homogenous freezing and heterogeneous nucleation scheme is newly implanted.Combined with a single mountain thunderstorm case,some sensitivity tests are used to investigate the impact of atmospheric ice nucleus concentration on microphysical processes and precipitation.Simulation results show:(1)The change of ice nucleus concentration will affect the dynamic field of the convective cloud and all the hydrometeors.As the concentration of ice nuclei increases,the concentration of ice crystals increases,and a large amount of latent heat is released during the condensation process,which leads to an increase in the vertical updraft.At the same time,the concentration of graupel particles in the cloud becomes larger.However,due to the limited water vapor content,each of the hydrometeors particles"races for"water vapor,the growth of cloud droplets,ice crystals and graupels is suppressed,and it is difficult to become a larger-sized precipitation particle.(2)The increase of ice nucleus concentration leads to the reduction of the scales of cloud droplets,which weakens the process of automatic conversion of cloud droplets into raindrops.The decrease in the mixing ratio of raindrops and cloud droplets inhibits the collection of droplets by raindrops.At the same time,small-scale graupel particles weaken the process of melting graupels into raindrops,which ultimately leads to a reduction in cumulative rainfall on the ground.

关 键 词：冰核 冰晶 对流云 降水 

分 类 号：P435[天文地球—大气科学及气象学]