Using GOES ABI Split-Window Radiances to Retrieve Daytime Low-Level Water Vapor for Convective Forecasting

A clear sky, daytime retrieval of low-level precipitable water vapor based on the single-layer approximation to the radiative transfer equation applied to three longwave window channels is described. The algorithm, which simultaneously retrieves skin temperature and air temperature as well, has the advantage of using satellite radiances only—no ancillary information is needed. Application of the method to Geostationary Operational Environmental Satellite (GOES)-16 Advanced Baseline Imager (ABI) radiance observations at 10.3, 11.2 and 12.3 µm demonstrates its utility in monitoring the location of low-level water vapor in the warm season, pre-convective atmosphere over the United States.