ESTIMATING THE NET SURFACE SHORTWAVE RADIATION USING MODIS DATA

Net Surface Shortwave Radiation (NSSR) is a key quantity for the estimation of net radiation (𝑅𝑛) and 𝑅𝑛 is a key component of the Earth energy balance. The most practical and reliable method for estimating solar radiation is based on remote sensing because remote sensing observation values are practical than location based measurements. It has been observed that existing ancillary data are not sufficient to have an accurate solar radiation estimates due to the limited amount of ground equipments. This research tries to provide accurate solar radiation databasedonthedataandproductsfromModerateResolutionImagingSpectroradiometer (MODIS), on board the Earth Observing System (EOS) Terra satellite, as an alternative solution for existing unreliable pyranometer data. The primary objective of this research is to explore an appropriate methodology to capture the spatial distribution of NSSR. In addition, this study describes the methods for estimating instantaneous and daily average NSSR using different algorithms. By this developed model, the average RMSE value for estimated instantaneous NSSR is 29.44Wm−2,55.51Wm-2 and 44.43Wm-2 for the clears ky, cloudy sky and both clear and cloudy sky condition respectively. For the estimated daily average NSSR, value of average RMSE is 29.53Wm−2,31.83Wm-2 and 30.70Wm-2 for the clear sky, cloudy sky and both clear and cloudy sky condition respectively. Lastly Instantaneous NSSR and Daily average NSSR also mapped over the study area.