The estimation of surface daily reflected solar radiation using Landsat-7 ETM+ and empirical models

The ground surface daily reflected solar radiation (DRSR) reflects the interaction between solar radiation and ground surface, thus plays a significant role on the energy exchange between surface and atmosphere. In the paper, empirical models and Landsat-7 ETM+ data are used to estimate surface daily reflected solar radiation (DRSR) in Chengdu, China. Firstly, empirical models are used to calculate daily global solar radiation (DGSR)in 3 locations in and around the study area, then interpolating to any site of the whole region. After that, surface albedo is integrated from surface reflectance factors calculated from multi-spectral data from the Landsat-7 ETM+. Thirdly, the surface DRSR is computed by multiplying DGSR by surface albedo. Finally, the calculated DRSR is checked with measured data. The result shows a good agreement between estimated and measured DRSR, thus the method presented can be used to estimate DRSR with relatively low margin of error in the region that the data of DRSR is unavailable.