Retrieval of aerosol optical thickness over land surfaces from top‐of‐atmosphere radiance
Retrieval of aerosol optical thickness over land surfaces from top‐of‐atmosphere radiance
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DOI：
10.1029/2001jd002018
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发表时间：
2003-05
影响因子：
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通讯作者：
W. V. Hoyningen-Huene;M. Freitag;J. Burrows
中科院分区：
文献类型：
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作者：
W. V. Hoyningen-Huene;M. Freitag;J. Burrows
[1]气溶胶遥感需要能够确定陆地表面气溶胶光学厚度的技术，因为最重要的来源（大陆气溶胶、人为气溶胶、生物质燃烧、沙漠灰尘、火山爆发等）都在大陆上。本文提出了一种利用海洋水色型仪器（如海洋水色温度传感器（OCTS）、海洋观测广域传感器（SeaWiFS）、中分辨率成像传感器（MODIS）或中分辨率成像传感器（MERIS））从大气层顶（TOA）辐射反演陆地表面AOT的方法。计划将其作为ENVISAT辐射计SCIAMACHY和MERIS的离线程序。该方法是基于AOT和气溶胶反射率之间的查找表（LUT）的波长<0.67 μm。气溶胶的反射率是由TOA反射率和瑞利路径反射率以及表观光谱表面反射率计算得到的。在陆地上的地表反射率估计的混合模型的裸露土壤和绿色植被光谱，调整的归一化差分植被指数（NDVI）的卫星场景。该方法已被测试和验证SeaWiFS数据和封闭实验LACE-98（林登伯格气溶胶凝结实验）的气溶胶特性。对于短波信道（0.412-510 μm），反演数据与地面数据的符合率为20%。因此，该方法能够调查AOT在陆地上，产生区域混浊度的情况，以及识别气溶胶源，如大城市，大型火灾羽流，烟雾，小规模的动力学事件，也薄卷云。
[1] Aerosol remote sensing requires techniques enabling the determination of aerosol optical thickness (AOT) over land surfaces, because the most important sources (continental aerosols, anthropogenic aerosols, biomass burning, desert dust, volcano eruptions and others) are on continents. Here a retrieval method for the AOT over land surfaces from top-of-atmosphere (TOA) radiance using nadir looking instruments of the ocean color type (like Ocean Color and Temperature Sensor (OCTS), Sea viewing Wide Field Sensor (SeaWiFS), Moderate resolution Imaging Sensor (MODIS) or Medium Resolution Imaging Sensor (MERIS)) is presented. It is scheduled as an off-line procedure for the ENVISAT radiometers SCIAMACHY and MERIS. The method is based on lookup tables (LUT) between the AOT and the aerosol reflectance for wavelength <0.67 μm. The aerosol reflectance is obtained from TOA reflectance accounting for Rayleigh path reflectance and the apparent spectral surface reflectance. Over land the surface reflectance is estimated by a mixing model of bare soil and green vegetation spectra, tuned by the normalized differential vegetation index (NDVI) of the satellite scene. The method has been tested and validated with SeaWiFS data and with aerosol properties of the closure experiment LACE-98 (Lindenberg Aerosol Charactrization Experiment). For short wave channels (0.412–510 μm) an agreement between the retrieved and ground-based data of 20% is achieved. Thus the method enables the investigation of AOT over land, yielding the regional turbidity situation as well as the identification of aerosol sources like large cities, large fire plumes, haze, small scale dynamical events and also thin cirrus clouds.