敦煌沙尘气溶胶质量浓度垂直特征个例分析  

Profiling of Dust Aerosol Mass Concentration over Dunhuang:Case Studies

作　　者：华雯丽 韩颖 乔瀚洋 王天河[1] 黄忠伟[1] 闭建荣[1] 周天[1] HUA Wenli;HAN Ying;QIAO Hanyang;WANG Tianhe;HUANG Zhongwei;BI Jianrong;ZHOU Tian(Key Laboratory for Semi-Arid Climate Change of the Ministry of Education,College of Atmospheric Sciences,Lanzhou University,Lanzhou 730000,Gansu,China)

机构地区：[1]兰州大学半干旱气候变化教育部重点实验室,甘肃兰州730000

出　　处：《高原气象》2018年第5期1428-1439,共12页Plateau Meteorology

基　　金：国家自然科学基金项目(41375031;41430425;41775022);兰州大学中央高校基本科研业务费专项资金(lzujbky-2017-67)

摘　　要：针对兰州大学半干旱气候与环境观测站在敦煌地区的沙尘气溶胶加强观测试验,选取2012年春季自然和污染沙尘两种典型天气个例,利用激光雷达退偏观测的优势分离粗(沙尘)、细(背景气溶胶)粒子,反演并对比分析了沙尘气溶胶消光系数及质量浓度的垂直分布特征。研究发现,以4月26日为代表的自然沙尘,粒子退偏比垂直廓线均大于30%,质量浓度呈现单峰结构,1.5 km出现最大值(1 070μg·m^(-3));以4月6日为代表的污染沙尘,有明显的气溶胶分层现象,粒子退偏比介于5%～20%,沙尘质量浓度介于2～45μg·m-3;由于局地污染的影响,污染沙尘的质量消光系数(0.79m^2·g^(-1))明显大于自然沙尘(0. 48 m^2·g^(-1))。因此,为了准确评估沙尘气溶胶的质量浓度,对沙尘天气进行分类,并利用粒子退偏比有效分离沙尘气溶胶尤为重要。Dunhuang is located in the dust source area and also heavy industry base,natural dust events and pollution dust weather are its typical weather process.Therefore,this paper aims at the typical characteristics of dust weather in Dunhuang,using the data of Micro Pulse Lidar（MPL） and Photometer CE318 based on intensify observation of Semi-Arid Climate and Environment Observatory of Lanzhou University（SACOL） in Dunhuang.Applying the detection advantages of laser lidar polarization technology,combining local weather character,two cases of typical dust weather in spring 2012 were chosen to be quantitatively analyzed.According to dust depolarization ratio from observation,coarse particle（dust aerosol） and fine particle（background aerosol） were separated to retrieve their extinction coefficients and mass concentrations vertical distribution.In natural dust day,represented by 26 April 2012,appearing a strong dust layer,the particle depolarization ratio profile totally larger than30% with the strong asphericity.Due to the influence of aerosol particle size distribution and its composition,the aerosol lidar ratio gradually decreases in the whole period.At 18：45 on 26 April 2012,the extinction coefficient and mass concentration profile both appeared the single-peakstructure and the maximum value of were Mm^-1 and 1070 μg·m^-3 at 1.5 km.In polluted dust day,represented by 6 April 2012,three parent vertical aerosol layers were observed demonstrating obvious aerosol stratification and mixing.At 16：55 on 6 April 2012,the particle depolarization ratio was 5% ～ 20% and the mass concentration was 2 ～ 45 μg·m^-3.On the bottom aerosol layer,local pollution contributed most and fine aerosol mass concentration was about 17 μg·m^-3 at 1.5 km; dust from long distance transport contributed most in middle（2.5 ～ 3.7 km） and top（5.5 ～ 7.2 km） aerosol layer,and dust mass concentration were 29 μg·m^-3 and 18 μg·m^-3.Compared with the natural dust weather,there is a strong heterogeneity in polluted

关 键 词：敦煌 沙尘气溶胶 激光雷达 质量浓度 

分 类 号：P407.5[天文地球—大气科学及气象学]