Hirose, M., S. Shige, T. Kubota, F. A. Furuzawa, H. Minda, and H. Masunaga, 2021: Refinement of surface precipitation estimates for the Dual-frequency Precipitation Radar on the GPM Core Observatory using near-nadir measurements. J. Meteor. Soc. Japan, 99,
Special Edition on Global Precipitation Measurement (GPM): 5th Anniversary,
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This study attempts to improve surface precipitation estimates from GPM Core Observatory Dual-Frequency Precipitation Radar (DPR). We updated the low-level precipitation rate profiles (LPPs) using an a priori near-nadir database. The angle-bin difference in the detectability of shallow storms was examined to estimate the effect of missing shallow storms. We constructed a priori lookup tables constrained by the clutter-free bottom level and spatially averaged shallow precipitation fractions for the shallow precipitation deficiency (SPD) correction. Overall, these two corrections increase precipitation by 8% over land and 11% over ocean. These corrections mitigate approximately half of the incidence angle dependency over land and reduce the discrepancies from other global precipitation datasets.
- GPM DPR KuPR Version 06A data contain precipitation anomalies of −7% over land and −2% over ocean.
- The LPP correction increases precipitation, in particular, at high altitudes and at middle and high latitudes. The LPP correction results in a 5% global increase in precipitation.
- The SPD correction enhances precipitation by 6%. The impact reaches 50% over specific low-rainfall oceans in the sub-tropics and at high latitudes.
- The difference of KuPR precipitation compared to satellite-gauge blended products is reduced from ‒17% to ‒9%.