摘要
为了解气溶胶以及云凝结核(cloud condensation nuclei,CCN)活化谱的垂直分布特征,利用2014年7月30日在山西开展的机载和地面观测获得的气溶胶和CCN数据,分析研究了CCN活化谱函数(N=C·S^k)参数C和k的垂直分布规律和气溶胶的活化特征。结果表明:本次过程气溶胶的垂直分层明显,不同区域气溶胶的垂直分布存在差异,按照位温变化特征自下而上可分为四层,气溶胶数浓度、有效直径和粒子谱等垂直分布特征和层结特性关系密切,CCN活化谱参数k受气溶胶的化学组分及粒子谱共同影响,四层的k值差异较大,其中第一层k值随着高度增大,最大值为1,第二层的k先减小后增大,在1700~2000 m处最低,为0.3,第三层的k变化不大,在0.8左右,第四层稳定到0.6。观测区域气团后向轨迹模拟结果显示:不同高度层气溶胶来源差异较大,1000和2000 m高度的气团分别来源于山西东南方向的华北平原和西侧的黄土高原,3000 m以上的高空气团来源于西北方的蒙古国。各层C、k结果与相应来源地的地面CCN活化谱的观测结果有较好的对应关系,气溶胶的性质与相应来源地的地面气溶胶性质较为一致。不同高度气溶胶来源差异是导致气溶胶分布以及CCN活化谱存在明显分层的原因。
In order to study the vertical distribution of aerosol and cloud condensation nuclei(CCN)spectra,we combind the aerosol data with CCN data from aircraft and surface observations conducted in Shanxi on 30 July 2014 to analyze the vertical distribution of the parameters C and k of the CCN spectrum(N=C·S^k)and the activation characteristics of aerosols.The results show that the vertical stratification of aerosols in this process is obvious,and the vertical distribution of aerosols in different regions is different.According to the characteristics of potential temperature change,it can be divided into four layers from bottom to top.The vertical distribution characteristics such as aerosol concentration,effective diameter and particle spectrum are closely related to the stratification.The k is affected by the aerosol’s chemical composition and the particle spectrum,and the k of each layer is different.The k value of the first layer increases with height and the maximum value is 1.The k value of the second layer decreases first then goes up.It is the lowest between 1700 m and 2000 m,being 0.3.The third layer has little change in k,about 0.8,and the fourth layer stabilizes to 0.6.The aerosol sources are different in each layer by the backward trajectory modeling,and the properties of the aerosol are consistent with the ground aerosol properties of the corresponding source.The air masses at heights of 1000 m and 2000 m from the North China Plain in the southeast of Shanxi and the Loess Plateau to the west,respectively.The air mass above 3000 m is from Mongolia in the northwest.So,differences in vertical aerosol sources are responsible for the apparent stratification of the aerosol distribution and CCN spectrum.
作者
杨怡曼
周毓荃
蔡兆鑫
YANG Yiman;ZHOU Yuquan;CAI Zhaoxin(Nanjing University of Information Science and Technology,Nanjing 210044;Chinese Academy of Meteorological Sciences,Beijing 100081;Weather Modification Office of Shanxi Province,Taiyuan 030002;College of Global Change and Earth System Science,Beijing Normal University,Beijing 100875)
出处
《气象》
CSCD
北大核心
2020年第9期1199-1209,共11页
Meteorological Monthly
基金
国家重点研发计划(2016YFA0601700)
国家自然科学基金项目(41805111)
山西省气象局重点项目(SXKZDRY20185106)共同资助。
关键词
气溶胶
CCN
垂直分布
活化特性
飞机观测
aerosol
cloud condensation nuclei(CCN)
vertical distribution
activation characteristics
aircraft observation
