Estimation of path-average rain drop size distribution using the NASA/TRMM microwave link

Abstract

Microwave attenuation measurements at 25 GHz, and 38 GHz on the NASA/TRMM 2.3-km microwave link permit the application of a dual-wavelength inversion technique to estimate parameters of a path-average gamma drop size distribution (DSD). Three Joss-Waldvogel disdrometers provide DSD measurements under the link path permitting direct comparison with the estimated DSD. Additionally, the estimated and measured DSDs are used to compute path-average rain rates and rainfall accumulation. These results are compared to path-average measurements from the network of optical and tipping bucket rain gauges.