摘要
为了解沙尘传输过程中气溶胶粒子光学性质的变化,利用2001—2008年中国北方4个站点沙尘期间的数据资料,比较分析了沙尘源区与下游地区气溶胶光学特性的差异。结果表明,沙尘期间大量粗粒子对总消光具有强烈贡献,沙尘源区和下游地区粗粒子消光分别占总消光的85.2%和65.8%。沙尘期间沙尘源区与下游地区均表现出较高的气溶胶光学厚度;而源区的Angstrom波长指数明显低于下游地区,当沙尘暴出现时会下降到零甚至负值。沙尘源区与下游区气溶胶体积尺度谱以粗模态峰为主模态峰。在波长440～1 020nm时,气溶胶单次散射反照率随波长增大而增大,源区与下游地区的单次散射反照率分别达到0.95和0.92。沙尘源区气溶胶的不对称因子大于下游地区,4个波段的平均不对称因子分别为0.73和0.70。
The purpose of this study is to investigate the variation of aerosol optical properties during the dust long-range transport process.A comparison of aerosol optical properties was performed between Dunhuang,Yulin as source regions and Beijing,Xianghe as downwind regions during dusty events from 2001 to 2008.Compared with the fine particles,the coarse particles（r0.6 μm） became relatively more important for the total extinction because of the appearance of considerable coarse particles during dust events.The extinction of coarse particles（r0.6 μm） accounted for about 85.2% of the total particles at 440,670,870 and 1 020 nm over dust source regions,and 65.8% over downwind regions.During dusty days,the aerosol optical depth showed a high value over source and downwind regions.Angstrom indexes over source regions were smaller than on downwind regions,and decreased to zero or negative when the severe dust storm occurred.Coarse modes was the principal in aerosol volume size distribution spectra over source and downwind regions,with the volume concentration ratio of coarse to fine modes being 23 and 33 in source regions,and decreasing to about 8 in downwind regions.The single scattering albedo showed an increasing trend with wavelengths during dusty days,being 0.95 and 0.92 over source and downwind regions respectively.The average asymmetry factor at the four wavelengths in dust source regions（0.73） was larger than that in downwind regions（0.70）.
出处
《中国沙漠》
CSCD
北大核心
2012年第6期1710-1715,共6页
Journal of Desert Research
基金
国家自然科学基金项目(41005089)
高等学校博士学科点专项科研基金项目(20103228120004)
江苏省高校自然科学研究资助项目(10KJB170009
10KJB170008)
江苏高校优势学科建设工程资助项目(PAPD)共同资助
关键词
沙尘
气溶胶
长距离传输
光学特性
dust
aerosol
long-range transport
optical properties
