263 Polarimetric Radar QPE Based on a New Differential Phase-Based Variational Approach

Thursday, 31 August 2017
Zurich DEFG (Swissotel Chicago)
Hao Huang, Nanjing Univ., Nanjing, China; and K. Zhao and G. Zhang

Quantitative precipitation estimation (QPE) with polarimetric radar observations suffers from different sources of uncertainty. The variational method appears to be a promising way to optimize the radar QPE statistically. In this study, a new variational approach is developed to quantitatively estimate rainfall rate (R) from the differential phase (ΦDP). A spatial spline filter is utilized in the optimization procedures to eliminate the impact of the random fluctuations in ΦDP, which can be the major error source in the specific differential phase (KDP)-based QPE. Additional constraints such as the self-consistency with the horizontal reflectivity factor (ZH) and the differential reflectivity (ZDR) can be incorporated into the variational framework easily. The approach is evaluated by an idealized case and a real rainfall case observed by an operational S-band polarimetric radar in South China. The results demonstrate that with a proper spatial filter used, the proposed variational radar QPE agrees well with the rain gauge observations.
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