Aircraft profiles of aerosol microphysics and optical properties over North America: Aerosol optical depth and its association with PM2.5 and water uptake
Aircraft profiles of aerosol microphysics and optical properties over North America: Aerosol optical depth and its association with PM2.5 and water uptake
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DOI：
10.1029/2006jd007918
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发表时间：
2007-06
影响因子：
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通讯作者：
Y. Shinozuka;A. Clarke;S. Howell;V. Kapustin;C. McNaughton;Jingchuan Zhou;B. Anderson
中科院分区：
文献类型：
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作者：
Y. Shinozuka;A. Clarke;S. Howell;V. Kapustin;C. McNaughton;Jingchuan Zhou;B. Anderson
气溶胶柱光学深度（AOD）与气溶胶的直接辐射效应有关，是很容易获得的卫星产品。2.5 μm空气动力学干气溶胶的质量，即PM2.5，是在选定的区域站点测量地表气溶胶污染的常用指标。这两个参数之间的联系将提供一种方法来推断PM2.5及其在卫星观测到的广大地区的变化。这需要确定气溶胶干质量对环境湿度的广泛可变影响的响应及其对柱AOD的光学贡献。在INTEX-North America飞机活动期间，我们获得了72条10公里范围内可见气溶胶光散射及其对水分吸收的响应曲线。从这些测量中确定的环境AODs，以及在靠近地面AERONET的三个剖面上确认的AODs，除存在具有高气溶胶负荷的湿润边界层外，一般都低于0.4。由水分吸收引起的环境AOD的比例Wf为37±15%（平均值和标准差）。根据飞机测量的低空大小分布估计边界层PM2.5 （PM2.5代理）。尽管垂直气溶胶结构变化很大，但在去除4%的AOD为>.8,>90% RH的数据后，发现环境AOD与pm2.5代理的相关性为R2 = 0.77。研究结果为遥感反演地表PM2.5质量提供了依据。发现在柱积分基础上对质量与消光关系进行分层时，环境AOD的波长依赖性不如逐层分层有效。
[1] Aerosol column optical depth (AOD) is related to the aerosol direct radiative effect and readily available as a satellite product. The mass of dry aerosol up to 2.5 μm aerodynamic, or PM2.5, is a common measure of surface aerosol pollution at selected regional sites. A link between these two parameters would provide a way to infer PM2.5 and its change over extensive regions observed by satellites. This requires determination of the response of aerosol dry mass to the widely variable influence of ambient humidity and its optical contribution to column AOD. During the INTEX-North America aircraft campaign, we obtained 72 profiles of visible aerosol light scattering up to 10 km and its response to water uptake. The ambient AODs determined from these measurements, and confirmed for three profiles near surface AERONET, were generally below 0.4 except in the presence of a humid boundary layer with high aerosol loading. The fraction of ambient AOD due to water uptake, Wf, was found to be 37 ± 15% (average and standard deviation). Boundary layer PM2.5 was estimated (PM2.5proxy) from low-altitude size distributions measured from the aircraft. Despite the large variety of vertical aerosol structure, the ambient AOD was found correlated with the PM2.5proxy with R2 = 0.77, after 4% of data with AOD > 0.8 for >90% RH were removed. Our results support the application of remote sensing to retrievals of surface PM2.5 mass. The wavelength dependence of ambient AOD was found to be less effective in stratifying the mass versus extinction relationship on the column integral basis than on a layer by layer basis.