A Blended Satellite Total Precipitable Water Product for Operational Forecasting

Abstract

Total precipitable water (TPW), the amount of water vapor in a column from the surface of the earth to space, is used by forecasters to predict heavy precipitation. In this paper, a process for blending TPW values retrieved from two satellite sources is detailed: the Advanced Microwave Sounding Unit (AMSU) instruments on three NOAA satellites, and the Special Sensor Microwave Imager (SSM/I) instruments on three Defense Meteorological Satellite Program (DMSP) satellites. The process starts with a blending algorithm, which matches the cumulative probability distribution functions of TPW retrievals from the two instruments to lessen their differences. The data are then mapped to a map projection useful to forecasters and composited for 12 h to make a global map. These maps are produced hourly using Data Processing and Error Analysis System (DPEAS) software and made available to forecasters online.