Monday, 28 August 2023
Boundary Waters (Hyatt Regency Minneapolis)
This study investigates the performance of the ZPHI-based (ZPHI) and reflectivity-based power-law fitting (Z-fitting) methods for the liquid water content (LWC, g m-3) and radar estimated size (RES, mm) retrieval. These dual-wavelength retrieval algorithms utilize path-integrated attenuation (PIA) deduced from X- and K-band radars to estimate specific attenuation (A, dB km-1) at each range gate. The Observing System Simulation Experiments (OSSE) were conducted to investigate the Mie scattering effect on both algorithms. The dual-wavelength data from vertical pointing measurements of Taiwan Experiment Atmospheric Mobile – Radar ( TEAM-R, X-band) and Micro Rain Radar-PRO (MRR-PRO, K-band) during TAHOPE (Taiwan-Area Heavy rain Observation and Prediction Experiment) was applied to ZHPI and Z-fitting algorithms and validated to NCAR SPOL RHI retrievals.
In OSSE, the simulated reflectivity profiles with attenuation effects of both radar measurements were obtained from Joss-Waldvogel Disdrometer (JWD) via the T-matrix simulation. The retrieved A, LWC, and RES from the ZPHI outperformed the Z-fitting method.
The RMSE of the retrieved A (LWC, RES) from Z-fitting and ZHI are 0.22 (0.12, 0.25) and 0.18 (0.11, 0.27), respectively. In addition, a Mie scattering effect correction procedure was developed and applied to OSEE data. The correction shows a significant improvement of 6 to 12% reduction in RMSE of A.
The TEAM-R and MRR-PRO data from the intensive observation period (IOP) 3 during TAHOPE was applied to ZPHI and Z-fitting algorithms in the real case study. The results show that the Mie scattering correction procedure leads to noticeable improvements in ZPHI method. Furthermore, the ZPHI has more consistent retrievals with SPOL RHI estimations. Overall, the LWC and RES retrievals from ZPHI outperform the Z-fitting method.
Keywords: specific attenuation; retrieved liquid water content; Mie scattering effect; dual-wavelength technique
In OSSE, the simulated reflectivity profiles with attenuation effects of both radar measurements were obtained from Joss-Waldvogel Disdrometer (JWD) via the T-matrix simulation. The retrieved A, LWC, and RES from the ZPHI outperformed the Z-fitting method.
The RMSE of the retrieved A (LWC, RES) from Z-fitting and ZHI are 0.22 (0.12, 0.25) and 0.18 (0.11, 0.27), respectively. In addition, a Mie scattering effect correction procedure was developed and applied to OSEE data. The correction shows a significant improvement of 6 to 12% reduction in RMSE of A.
The TEAM-R and MRR-PRO data from the intensive observation period (IOP) 3 during TAHOPE was applied to ZPHI and Z-fitting algorithms in the real case study. The results show that the Mie scattering correction procedure leads to noticeable improvements in ZPHI method. Furthermore, the ZPHI has more consistent retrievals with SPOL RHI estimations. Overall, the LWC and RES retrievals from ZPHI outperform the Z-fitting method.
Keywords: specific attenuation; retrieved liquid water content; Mie scattering effect; dual-wavelength technique
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