BRDF/Albedo retrievals from the Terra and Aqua MODIS systems at 500-m spatial resolution and 10-day intervals

Surface bi-directional reflectance distribution function (BRDF) and albedo properties are retrieved over the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) area. A landcover-based fitting approach is employed by using a newly developed landcover classification map and the MODIS 10-day surface reflectance product (MOD09). The surface albedo derived by this method is validated against other satellite systems (e.g. Landsat-7 and MISR) and ground measurements made by an ASD spectroradiometer. Our results show good agreements between the datasets in general. The advantages of this method include the ability to capture rapid changes in surface properties and an improved performance over other methods under a frequent presence of clouds. Results indicate that the developed landcover-based fitting methodology is valuable for generating spatially and temporally complete surface albedo and BRDF maps using MODIS observations.

在大气辐射测量（ARM）计划的南大平原（SGP）区域反演了地表双向反射分布函数（BRDF）和反照率特性。通过使用新开发的土地覆盖分类图和中分辨率成像光谱仪（MODIS）10天地表反射率产品（MOD09），采用了一种基于土地覆盖的拟合方法。用这种方法得出的地表反照率通过与其他卫星系统（例如陆地卫星 - 7和多角度成像光谱仪（MISR））以及由ASD光谱辐射计进行的地面测量进行了验证。我们的结果总体上显示数据集之间具有良好的一致性。这种方法的优势包括能够捕捉地表特性的快速变化，以及在频繁有云的情况下比其他方法性能更优。结果表明，所开发的基于土地覆盖的拟合方法对于利用MODIS观测生成空间和时间上完整的地表反照率和BRDF图是有价值的。