Introducing a Method for Replacement of MODIS Measured Radiance Fluxes Using Modified CRTM Model at the Local Scale

In this study, a method for replacing MODIS measured flux densities using CRTM is introduced. For this, the Radiosonde measured temperature profiles in Bandar-abbass synoptic station along with night time flux densities measure by MODIS sensor on board of Aqua platform for the deep water region in the Persian Gulf were used. Then, using standard predictors of OPTRAN version VIII which is the main part of CRTM model, it was tried to model the difference between modeled and MODIS measured radiance values. To evaluate the method, the averaged RMSE were used. The RMSE between CRTM calculated and MODIS measured radiation fluxes was found to be 0.47 . This value was improved to 0.39 using modified CRTM. The equivalent brightness temperature for these fluxes was 6.45 and 5.27 (K) respectively. So using the suggested method in this study, the CRTM calculated radiances fairly approaches the MODIS measured values. It is suggested that this method be used whenever there are high noises, cloud overcast and or any possible malfunctioning of MODIS sensor to replace the missing data.