A simplified method for the measurement of the atmospheric water vapor is presented. A multifrequency microwave radiometer having two different beamwidth antennas is used to measure solar extinction in terms of the difference temperature of the antennas and the relative intensity at each pair of different frequency points. The atmospheric emission component and the effect of solar fluctuation are removed automatically. Cloud absorption can be estimated by simultaneous measurement at two different frequency pairs and compensated for by the water vapor absorption. Using the specific nature of the composite weighting function defined in the opacity integral, the radiometric data can be related to the integrated water vapor and the water vapor profile. >
['Shinobu Hashimoto']
A new simplified water vapor measurement using a multifrequency microwave radiometer with two-different-beamwidth antennas