摘要
利用2011年和2013年夏秋季在青藏高原中东部开展的11架次气溶胶特征飞机观测数据,分析气溶胶数浓度、数谱及核化相关特征。结果表明:受天气系统、地形和地表影响,观测区内气溶胶数浓度(N_(a))和体积直径(D_(v))的垂直和水平分布差异较大,N_(a)呈西北高、东南低,D_(v)低层大、高层小,局地中高层有沙尘。格尔木盛行东风时,云降水对低层气溶胶有清除作用,N_(a)和D_(v)明显降低,6.2 km高度和7.2~7.4 km高度的中高空受高原大风或对流影响形成沙尘;盛行西风时,低层D_(v)以0.5~0.8μm为主,随高度升高和风速增大N_(a)升高,D_(v)变幅较小,6.2 km高度也有沙尘;不同天气系统影响下6.5 km高度以上均输入亚微米颗粒,N_(a)达5×10^(3)cm^(-3),8.0 km高度盛行东风时比西风时N_(a)更高,D_(v)更小,谱垂直分布也有以上特征,整层输入以偏北或偏西路径为主。不同过饱和度测量云凝结核数浓度(N_(ccn))表明,除格尔木6.0 km高度以下核化率(N_(ccn)/N_(a))在21%~47%外,其他观测区平均核化率介于1%~16%,6.0~8.5 km高度的核化率总体偏低;当N_(a)增加时核化率明显下降,且过饱和度1%~2%,-15~-5℃层或粒径1~3μm时的核化率相对偏高。
The central and eastern Qinghai-Tibet Plateau is the birthplace of the Yellow River,the Yangtze River and the Lancang River.It is also a climate change sensitive area and a key ecological protection area.Based on observations of 11 sorties conducted in summer and autumn of 2011 and 2013,the vertical distribution of aerosol number concentration and number spectrum at Golmud,and the transport characteristics as well as the horizontal distribution and nucleation characteristics of aerosol number concentration and cloud condensation nuclei(CCN)number concentration at mid-altitude of the central and eastern Plateau are analyzed.The results indicate that the vertical and horizontal distributions of aerosol number concentration(Na)and volume diameter(Dv)in the central and eastern Qinghai-Tibet Plateau are significantly different due to the influence of weather system,topography,and surface characteristics.The aerosol number concentration is high in the northwest and low in the southeast.The volume diameter is large in the lower layer,small in the upper layer,and there are dust layers in the middle and upper layers.Precipitation has clear effects on low-level aerosols when east wind prevails at Golmud,and the aerosol number concentration and volume diameter are significantly reduced.At the same time,due to plateau gale or convection,sand and dust layers also form at the middle and upper altitudes of 6.2 km and 7.2-7.4 km.The aerosol volume diameter of the lower layer is 1.8μm mainly when westerly wind prevails,the number concentration increases with the increase of height and wind speed,the variation of aerosol volume diameter is small,and the sand and dust layer also appears at 6.2 km altitude.Under the influence of different weather systems over 6.5 km altitude,submicron particles are imported,and the number concentration even reaches 5×10^(3)cm^(-3).Moreover,the aerosol number concentration and particle size imported at about 8.0 km altitude when east wind prevails are denser and smaller than those imported when wes
作者
马学谦
郭学良
刘娜
张玉欣
韩辉邦
康晓燕
Ma Xueqian;Guo Xueliang;Liu Na;Zhang Yuxin;Han Huibang;Kang Xiaoyan(Qinghai Province Weather Modification Office,Xining 810001;Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029)
出处
《应用气象学报》
CSCD
北大核心
2021年第6期706-719,共14页
Journal of Applied Meteorological Science
基金
第二次青藏高原综合科学考察(2019QZKK0104)
国家自然科学基金项目(41665008,41565008,41705121)
国家重点研发计划(2019-YFC1510302)。
关键词
青藏高原中东部
飞机观测
气溶胶
核化
the central and eastern Qinghai-Tibet Plateau
aircraft measurement
aerosol
nucleation
