A Method for Retrieving Land Surface Reflectance Using MODIS Data

Surface reflectance retrieval is an important step in the data processing chain for the extraction of quantitative information in many applications. The aim of this paper is to develop a method for retrieving surface reflectance and aerosol optical depth simultaneously over both dark vegetated surfaces and bright land surfaces. After applying this method to the Moderate Resolution Imaging Spectroradiometer (MODIS) data in the Heihe River Basin of China, aerosol optical depth and surface reflectance values of these regions are calculated. The retrieved surface reflectance from MODIS is consistent with measured reflectance from Analytical Spectral Device (ASD) Field Spec spectral radiometer, with R-squared (R²) greater than 0.84 and root mean square error (RMSE) of 0.027 at band 1 (0.66 μm), 0.015 at band 3 (0.47 μm), and 0.017 at band 4 (0.55 μm). The R² of MOD09 with ASD measured surface reflectance is around 0.60, and RMSE are 0.049 at band 1, 0.024 at band 3, and 0.036 at band 4 .