夹卷混合过程对青藏高原云滴谱及微物理量影响的数值模拟研究  

Numerical simulation of the effects of entrainment-mixing on cloud droplet size distributions and microphysical properties over the Tibetan Plateau

作　　者：罗仕 陆春松[1] 郭小浩 李扬[3] 薛舒航 

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,南京210044 [2]南京信息工程大学气候与环境变化国际合作联合实验室,南京210044 [3]南京信息工程大学气象灾害预报预警与评估协同创新中心,南京210044 [4]南京信息工程大学中国气象局气溶胶与云降水重点开放实验室,南京210044

出　　处：《中国科技论文》2017年第9期972-977,共6页China Sciencepaper

基　　金：国家自然科学基金资助项目(91537108;41305120);公益性行业(气象)科研专项基金资助项目(GYHY201406001);高等学校博士学科点专项科研基金资助项目(20133228120002);江苏省自然科学基金资助项目(BK20160041);江苏省"六大人才高峰"项目(2015-JY-011);江苏省第五期"333工程"培养资金资助项目(BRA2016424);江苏省2014年度高校"青蓝工程"培养项目

摘　　要：夹卷混合过程对云滴谱(cloud droplet size distribution,CDSD)具有重要影响。在1个考虑夹卷混合过程的气泡模式中,利用青藏高原第3次大气科学试验(TEPEX-III)那曲观测站探空资料,通过敏感性试验,研究不同相对湿度(relative humidity,RH定义为Φ)的环境空气被夹卷进入云之后对云滴谱及微物理量的影响。结果表明:夹卷过程的稀释作用使绝热云滴谱中各个尺度云滴的数浓度同等程度的减少,但谱型不变。夹卷空气的Φ值越低,云滴蒸发越强,为了使空气达到饱和需要更多的云滴完全蒸发,因此在混合过程中云滴的数浓度、体积平均半径、含水量减幅越大,混合过程完成后这些量越小,云滴谱内小云滴数浓度越大,峰值数浓度越低且其对应半径越小,谱越宽。基于以上模式结果,夹卷混合过程会使得云滴谱向小滴方向增宽,导致小云滴数量大幅增加大云滴数量减少,抑制云中降水的形成,减弱对流的发展。Entrainment and mixing processes have a significant effect on cloud droplet size distribution（CDSD）.In this study,a parcel model considering entrainment-mixing processes is used to explore the influence of entrained environmental air on CDSD and microphysical properties with sounding data from TEPEX-IIINaqu station,by sensitivity experiments with different relative humidity（Φ）in the entrained dry air.The results show that the dilution of entrained air makes number concentrations of all size droplets with different sizes in adiabatic CDSD simultaneously decrease,but the shapes of CDSDs do not change.The lowerΦof entrained air means stronger evaporation of cloud droplets and more droplets evaporate completely,leading to stronger decrease of number concentration,mean-volume radius and liquid water content,smaller microphysical parameters and larger small droplet number concentrations,smaller maximum number concentration in CDSD and its corresponding radius,and further leading to wider CDSD to saturate the entrained air after mixing.Based on the former model results,entrainment and mixing process leads to broader CDSD,much bigger number of smaller droplets than that of large droplets,thus suppressing formation of precipitation and development of convention.

关 键 词：数值模拟 夹卷混合 云滴谱 微物理参量 

分 类 号：P426.51[天文地球—大气科学及气象学]