Improvements of Brightness Temperature Simulations for Validation of TRMM Rainfall Products

Abstract

Due to the scarcity of reliable validation data and difficulties associated with the collocation of validation data and satellite measurements, an approach for verifying Tropical Rainfall Measuring Mission (TRMM) rainfall products has been proposed. Consistency between TRMM Microwave Imager (TMI)-observed brightness temperatures (TBs) at 10.7 and 19.4 GHz channels and those simulated from the Precipitation Radar (PR) rainfall estimates using a radiative transfer model were statistically examined. Accurate and computationally efficient simulations of TBs are critical for this approach. In this study, convolution, a slant-path approximation, a melting-layer parameterization, and a drop size distribution (DSD) model employed in simulations of brightness temperatures are presented and evaluated. Impact of the melting-layer parameterization and the DSD model on simulated brightness temperatures and thus on validation results are also examined.