NESDIS "Hydro-Estimator" Estimates

Grid Resolution:~ 4 km
Domain: Global (60N-60S)

The Hydro-Estimator (H-E) is a highly modified adaption of the manual Interactive Flash Flood Analyzer (IFFA) that has been used by operational forecasters at the Satellite Applications Branch of NESDIS for 20 years. Like the IFFA, the H-E rainfall rates are based on 10.7-micron brightness temperature, and are modified according to moisture availability, convective equilibrium (to identify regions of warm-top convection) and orographic effects using Eta model parameters. However, unlike the IFFA, the H-E rainfall curve is a function not only of the temperature of the pixel of interest, but also of its surroundings--the colder the pixel is with relation to its surroundings, the higher the rainfall rate for a given brightness temperature value. Furthermore, pixels that are warmer than their surroundings are assumed to be inactive and producing no rainfall--a distinction that results in much better separation of raining and nonraining areas than a single threshold temperature value.