Abstract Empirical and statistical techniques have been used to examine a large dataset of near-nadir brightness temperature measurements at 19, 22 and 31 GHz over tropical oceans from the Satellite Microwave Radiometer (SAMIR) system onboard the Bhaskara-II satellite. Told water vapor data from NOAA-7 satellite have been used in an empirical correlation analysis in conjunction with the near-coincident SAMIR data to establish statistical relationships between brightness temperature and total water vapor under cloud-free conditions. Bi-spectral distributions of the SAMIR data have been analyzed through a partially supervised cluster analysis technique to separate the liquid water contaminated data based on their spectral response. From this analysis, approximate threshold brightness temperature values for the three SAMIR channels have been fixed, above which cloud liquid water effect dominates. In order to verify these threshold values, limited SAMIR data related to cloudy conditions have been examined in ...