Validation of high‐resolution satellite rainfall products over complex terrain

Abstract

High‐resolution satellite rainfall products, at daily accumulation and 0.25° spatial resolution, are evaluated using station networks located over two different parts of Africa. The first site is located over Ethiopia with a very complex terrain. The second site, located over Zimbabwe, has a less rugged topography. The evaluated satellite rainfall products are the NOAA‐CPC African rainfall estimation algorithm (RFE), TRMM‐3B42, the CPC morphing technique (CMORPH), PERSIANN, and the Naval Research Laboratory's blended product. These products perform reasonably well over both regions in detecting the occurrence of rainfall. However, performances are poor in estimating the amount of rainfall in each pixel. The correlation coefficients are low and random errors high. The performance was better over Zimbabwe as compared with Ethiopia. Comparing the different products, CMORPH and TRMM‐3B42 showed a better performance over Ethiopia, while RFE, CMORPH, and TRMM‐3B42 preformed relatively better over Zimbabwe.

Acknowledgements

This work was funded by a grant/cooperative agreement from the National Oceanic and Atmospheric Administration, NA050AR4311004, and NASA HQ Science Mission Directorate Cooperative Agreement Notice NN‐H‐04‐Z‐YO‐010‐C through Cooperative Agreement # 06CRAG0028 with the US Geological Survey. The views expressed herein are those of the author(s) and do not necessarily reflect the views of NOAA or NASA, or any of its sub‐agencies. We are very grateful to the National Meteorological Agency of Ethiopia, and its director Mr Kidane Asefa, for providing us with all the rain‐gauge data we requested free of any charges.