Measurements and interpretation of the microwave spectrum of the terrestrial atmosphere near 1-centimeter wavelength

Solar extinction measurements of the atmospheric absorption spectrum near 1-cm wavelength were made on 10 days during 1964. The 1.35-cm water vapor resonance varied in intensity and shape, and this variation can be correlated with simultaneous radiosonde measurements. The spectrum can be interpreted theoretically in terms of the water vapor content of the atmosphere with an altitude resolution of 15 km or less. The integrated water vapor content of the troposphere can be determined with an accuracy of approximately 5%, including uncertainties in the measurements and the atmospheric model. Theoretically, the integrated liquid water content of heavy clouds can be measured simultaneously with an rms accuracy of approximately 0.004 g/cm2, or 15%.