沙尘传输路径上气溶胶浓度与干沉降通量的粒径分布特征  

Size-Dependent Mass and Dry Deposition Fluxes of Atmospheric Aerosols along Dust Transport Routes

作　　者：闫涵[1] 高会旺[1] 姚小红[1] 石金辉[1] 于超 

机构地区：[1]中国海洋大学海洋环境与生态教育部重点实验室,青岛266100 [2]国家气象中心,北京100081

出　　处：《气候与环境研究》2012年第2期205-214,共10页Climatic and Environmental Research

基　　金：国家自然科学基金资助项目40976063

摘　　要：利用2002年春季中国北京、青岛和日本福冈3个地区的分级气溶胶浓度资料,结合改进的Wil-liams模型,分析了沙尘传输路径上空气动力学直径≤11μm气溶胶(PM11)浓度和干沉降通量的粒径分布特征,并估算了黄海海域春季PM11的干沉降通量及不同粒径气溶胶的贡献。结果表明:3个地区PM11浓度粒径分布在非沙尘时期呈双峰分布,两个峰值分别出现在细颗粒(<2.1μm)部分和粗颗粒(2.1～11μm)部分;沙尘时期,3个地区PM11浓度粒径分布均趋于单峰分布,峰值位于粗颗粒部分,并且越靠近沙尘源地,这种趋势越明显。较强沙尘天气时期,粗颗粒部分的浓度峰值粒径从沙尘源地附近到黄海西岸、东岸呈降低趋势,但在一般沙尘天气时期,这种现象并不明显。沙尘时期和非沙尘时期,3个地区粗颗粒的干沉降通量均随粒径增加而增大,细颗粒的干沉降通量随粒径的变化不明显。虽然沙尘时期粗颗粒沉降通量较非沙尘时期有明显增加,但粗颗粒对PM11干沉降通量的贡献与非沙尘时期相比,并没有明显的变化。较强沙尘天气时期,3个地区粗颗粒的干沉降通量明显高于一般沙尘天气时期;细颗粒的干沉降通量较一般沙尘天气时期略有增加。黄海海域春季沙尘时期PM11的干沉降通量约为31.70～58.59mg.m-2.d-1,非沙尘时期约为8.33～15.94mg.m-2.d-1。粗颗粒是黄海海域春季PM11干沉降通量的主要贡献者,约占PM11干沉降通量的94.2%以上。Using the size-segregated measurements of atmospheric aerosols collected in Beijing and Qingdao in China and Fukuoka in Japan during the spring of 2002, the size distributions of the mass of atmospheric aerosols with aerodynamic diameter （Dp） ≤ 11 μm （PMll） along dust transport routes are investigated. The size distribution of these aerosols in mass concentration during non-dust periods exhibits a bimodal pattern, i. e. , a fine modes with Dp〈 2.1 μm and a coarse mode between 2.1 μm and 11 μm On the other hand, the size distribution of these aerosols in mass concentration during dust periods attempts to exhibit a uni-modal pattern in the coarse particle size range. The coarse mode diameter decreases with the distance from the dust source zone to the west and east coast of the Yellow Sea during the heavy dust periods. It is not case in regular dust periods. The size-dependent dry deposition fluxes of the aerosols over the Yellow Sea in springtime are estimated using an improved Williams＇ model. The dry deposition fluxes increase with the increasing size in the coarse particle size range during the non-dust and dust periods. It appears that no evident variations occurred in the fine mode. The estimated PMll fluxes over the Yellow Sea during the dust and non-dust periods range from 31.70 to 58. 59 mg m^-2 ·d^-1 and ranged from 8. 33 to 15.94 mg · m^-2 · d^-1 , respectively. Although the dry deposition fluxes of the coarse particles increase evidently during dust periods, the relative contributions of the coarse particles to that of PMll do not change significantly regardless of the occurrence of and absence of dust events. The authors find that coarse particles are the main contributor to the PM11 dry deposition in springtime over the Yellow Sea, the percentage reaches over 94.2%.

关 键 词：气溶胶 沙尘天气 传输路径 粒径分布 干沉降通量 

分 类 号：P402[天文地球—大气物理学与大气环境]