Determination of water vapor and liquid water content by an iterative method

Summary A simple method of retrieving water vapor and liquid water content is presented and validated by applying the Special Sensor Microwave/Imager data using ground truth data from Japan. The method is based on an iterative technique which uses model functions of relating two geophysical parameters to brightness temperature. Water vapor is found by a model function of relating water vapor content to brightness temperature at 22.235 GHz. Liquid water content is found by two model functions. One function defines a level of clear sky condition, and the other gives a ratio of liquid water content to brightness temperature increased from clear sky conditions. The retrieved water vaporcontent is compared with upper air observations at Chichijima Island. The rms of errors is estimated at 3.3 Kg m^–2. The retrieved liquid water content is related to monthly precipitation observed at Chichijima Island, and a correlation coefficient of 0.68 is obtained.With 7 Figures