MICROWAVE TEMPERATURE-HUMIDITY PROBING OF THE ATMOSPHERE FROM SPACE

On the basis of statistical characteristics of the outgoing microwave radiation in a spectral range from 1 to 200 GHz calculated for a clear atmosphere, the number of independent components in the spectrum is s tudied in the case of global variations of temperature and humidity fo r two types of underlying surface--dry land and water. It is shown tha t present-day satellite remote sensors have an insufficient number of measuring spectral channels to retrieve all the information available in the spectra on the vertical profiles of temperature and humidity. C alculations of the information content of measurements point to a rela tively low informativeness of contemporary microwave radiometers compa red to a full radiation experiment (1500 measurements in a spectral ra nge from 1 to 200 GHz). The error matrices for remote sensing and for closed numerical experiments are calculated to study the accuracy of t emperature--humidity probing for various random errors, for global and local statistics, and for different vertical resolutions. It is shown that temperature profiles can be determined to an accuracy of 0.5-1.0 K in the full radiation experiment.