NASA - National Aeronautics and Space Administration

Attenuation of radar signals in rain increases with frequency while the variability of non-attenuated reflectivity of rainfall diminishes as resonance scattering effects become more pronounced at higher radar frequencies. At mmwavelength frequencies, attenuation often becomes the dominant factor responsible for apparent reflectivity changes in vertical. This study presents an attenuationbased method to retrieve vertical profiles of rain rate from nadir-pointing W-band (94 GHz) radars. The quantitative assessments of retrieval errors are discussed, and an illustration of the retrievals using measurements from the spaceborne 94 GHz CloudSat radar is shown. As a consistency check, the spaceborne W-band radar retrievals are compared with concurrent estimates from a groundbased weather surveillance radar.