Water vapor retrieval over cloud cover area on land

Water vapor under cloud cover area was retrieved with the combination of AMSR-E Brightness temperature and MODIS atmospheric profile. In order to retrieve water vapor, surface emissivity in clear sky was first estimated using AMSR-E brightness temperature, MODIS atmospheric profiles product and 1-Dimension Microwave Radiative Transfer Model (1DMRTM). And then, surface emissivity under cloud cover area was estimated using 7 days average of that in clear sky. Finally, water vapor was retrieved using the estimated emissivity, AMSR-E brightness and look up table built by 1DMRTM. The finally retrieved water vapor was verified using SuomiNet GPS water vapor. The correlation coefficient of the two is 0.72, and the RMSE is 10.95mm.