The dual beam airborne technique as a tool for validation of the TRMM rain radar retrieval

TRMM will be the first space observation platform with a precipitation radar (PR) on board. A key issue in the data processing of the PR is the correction for attenuation. In the standard algorithm, this correction is made using a K-Z power law relationship as K=a Z^b where a is adjusted using the ocean surface as a reference target. This paper argues that a dual beam airborne Doppler radar as ELDORA-ASTRAIA should be of great interest in the validation of TRMM. Attenuated reflectivities sampled from two viewing angles may be processed following the “stereoradar analysis”, or the new “dual beam algorithm” (proposed in this paper) to derive the unattenuated reflectivity Z, specific attenuation K, rainfall rate R, and the associated K-Z relationship at the ELDORA-ASTRAIA frequency (9.3 GHz). All this information greatly useful to validate TRMM is obtained with the flexibility of an airborne platform