Estimation of path-integrated attenuation and its nonuniformity from TRMM/PR range profile data

Range profile data from the surface echo of the Precipitation Radar (PR) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite enable the assessment of the nonuniformity of rainfall. The surface echo profile can be converted to a horizontal pattern of surface echo strength within the PR's footprint at off-nadir angles. Then, using the no-rain surface echo profile over ocean as a reference, the horizontal pattern of the path-integrated attenuation (PIA) can be estimated under moderate to heavy rainfall. Based on the horizontal pattern of the PIA, the nonuniform beam-filling parameter is estimated. However, this technique is applicable only to off-nadir angles and over ocean. Comparisons using ground-based radar data obtained simultaneously with TRMM data verify the effectiveness of this technique. Index Terms--Nonuniform beam filling (NUBF), surface echo, Tropical Rainfall Measuring Mission (TRMM).