Evaluation of Moderate Resolution Imaging Spectroradiometer land surface visible and shortwave albedo products at FLUXNET sites

Abstract

We evaluated the accuracy of Moderate Resolution Imaging Spectroradiometer (MODIS) Collections 4 and 5 shortwave and visible albedo products at 18 FLUXNET sites globally from 2000 to 2007. While the shortwave product has been evaluated at a number of field sites, this represents the first attempt to assess the visible product. The surface visible albedo product relies more on quality of the atmospheric correction because atmospheric molecular scattering and aerosol absorption and scattering have larger impact on visible radiation than that on infrared radiation. The results show that in general the MODIS Collection 4 visible albedo product has an overall negative bias of -0.015, with a standard deviation (SD) error of 0.014 and a correlation coefficient of 0.88. The numbers are -0.010, 0.015, and 0.87 for Collection 5 visible albedo products. MODIS Collection 4 shortwave albedo product has an overall negative bias of -0.009, with a SD error of 0.023 and a correlation coefficient of 0.82. The numbers are -0.008, 0.023, and 0.80 for Collection 5 shortwave albedo products. A comparison of the site-averaged albedos shows that Collection 4 visible (shortwave) albedo has a SD of 0.009 (0.017) and a correlation coefficient of 0.94 (0.90), similar to the Collection 5 SD of 0.008 (0.017) and the correlation coefficient of 0.95 (0.89). © Copyright 2010 by the American Geophysical Union.