华北地区一次气溶胶与浅积云微物理特性的飞机观测研究  

An in-situ Case Study on Micro Physical Properties of Aerosol and Shallow Cumulus Clouds in North China

作　　者：蔡兆鑫[1,2] 蔡淼 李培仁[1] 李军霞[1] 孙鸿娉[1] 杨怡曼[4] 任刚 高欣[5] CAI Zhaoxin;CAI Miao;LI Peiren;LI Junxia;SUN Hongping;YANG Yiman;REN Gang;GAO Xin(Weather Modification Office of Shanxi Province,Taiyuan 030032;Beijing Normal University,Beijing 100875;Key Laboratory for Cloud Physics,Chinese Academy of Meteorological Sciences,China Meteorological Administration,Beijing 100081;Fenghua District Meteorological Bureau,Ningbo,Zhejiang 315500;Shanxi Meteorological Service Center,Taiyuan 030002)

机构地区：[1]山西省人工降雨防雹办公室,太原030032 [2]北京师范大学,北京100081 [3]中国气象局中国气象科学研究院云雾物理实验室,北京100081 [4]宁波市奉化区气象局,浙江宁波315500 [5]山西省气象服务中心,太原030002

出　　处：《大气科学》2021年第2期393-406,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目41805111;山西省重点研发计划项目201803D31222;国家重点研发计划项目2018YFC1507901。

摘　　要：2014年8月15日,山西省人工降雨防雹办公室在山西忻州开展了气溶胶和浅积云的飞机观测,本文利用机载云物理资料,详细分析了华北地区气溶胶、云凝结核(CCN)和浅积云微物理特性及其相互影响。主要结论有:(1)此次过程的边界层高度约为3600 m,不同层结情况下,0.1~3μm尺度范围内的气溶胶粒子浓度N_(a)、有效直径D_(a)和CCN数浓度的垂直廓线明显不同,近地面Na可达2500 cm^(-3)。(2)CCN的主要来源为积聚模态、爱根模态或者核模态的气溶胶颗粒,0.2%过饱和度下,气溶胶活化率(AR)在各高度层的结果变化不大;0.4%过饱和度下,AR随着高度增加而降低。(3)后向轨迹模式分析表明,2 km以下的气溶胶主要来自于当地城市排放,由细颗粒污染物组成;2 km以上的气溶胶主要来源于中国西北和蒙古地区的沙漠,由亚微米沙尘组成,溶解度相对较低,可作为潜在的冰核。(4)本文细致分析了两块相邻浅积云(Cu-1和Cu-2)的云物理特性。Cu-1云底高度约4500 m,云厚约600 m,云体松散,夹卷较多;云中液态含水量(LWC)基本保持在0.5 g m^(-3),云粒子浓度Nc平均值为278.3 cm^(-3),云滴有效直径D_(c)整体在15μm以内;毛毛雨滴粒子浓度最大值为0.002 cm^(-3),云中几乎无降水粒子;粒子谱宽随着高度增加而增大,主要集中在30μm以内。Cu-2云底高度约3900 m,云厚约1200 m,云体密实;云中过冷水丰沛,LWC有多个超过1 g m^(-3)的区域,云顶附近出现冰晶,云中粒子从凝结增长状态直接进入到混合相态;积云内部粒子水平分布不均,同一高度N_(c)相差较大,最大可达1240 cm^(-3)。D_(c)随着高度增加而增大;粒子谱宽随着高度增加而拓展,最大可达1100μm,谱型由单峰向多峰转变;降水粒子和冰晶图像大多为霰粒子、针状和板状。An aircraft observation on aerosol and shallow cumulus clouds in Xinzhou was carried out by the Weather Modification Office of Shanxi Province on 15 August 2014.In this paper,the microphysical properties of aerosols,CCN(cloud concentration nuclei),shallow cumulus clouds,and their interactions in North China are analyzed in detail,based on the airborne cloud physics data.Main results are as following:(1)In this case,the height of the boundary layer is about3600 m,and the aerosol particle concentration(Na)near surface can reach 2500 cm^(-3).The vertical profiles of Na,aerosol effective diameter(D_(a))and CCN number concentration are obviously different under different stratification conditions.(2)The main source of CCN is aerosol particles in accumulation mode,Aegean mode or nuclear mode.The aerosol AR(activation rate)through the vertical layer does not change much under the 0.2% supersaturation condition,while decreases with height under the 0.4% supersaturation condition.(3)HYSPLIT4(Hybrid Single-Particle Lagrangian Integrated Trajectory)model analysis shows that aerosols below 2 km mainly come from local urban emissions,which are composed of fine particulate pollutants.Above 2 km,aerosols mainly come from deserts in northwestern China and Mongolia,which are composed of submicron sand and dust.They can be potential IN(ice nuclei)due to their low solubility.(4)The physical characteristics of two adjacent shallow cumulus clouds(Cu-1 and Cu-2)are also analyzed.Cu-1 is loose with a lot of entrainment.The cloud base height and cloud thickness are about 4500 m and 600 m,respectively.The LWC(liquid water content)in Cu-1 is basically maintained at 0.5 g m^(-3),while the average N_(c)(cloud particle concentration)is 278.3 cm^(-3) and Dc(cloud effective diameter)is overall within 15μm.The maximum Nd(drizzle droplet number concentration)is 0.002 cm^(-3),with almost no precipitation particles in Cu-1.The particle spectrum width increases with height,and ED(effective diameter)is mainly concentrated within 30μm.Cu-2 is much

关 键 词：气溶胶 CCN(cloud concentration nuclei) 浅积云 飞机观测 

分 类 号：P401[天文地球—大气物理学与大气环境]