Improvements in RPG clutter/precipitation discrimination for the WSR-88D

The goal of the AP Ground Clutter Mitigation Scheme is the elimination of ground clutter echoes that occur during anomalous propagation (AP) conditions in the atmosphere. The AP Ground Clutter Mitigation Scheme is being deployed in stages within the Weather Surveillance Radar-1988 Doppler (WSR-88D) network. Once fully deployed, this scheme will improve the quality of the radar base data by identification and removal of AP ground clutter echoes. The AP Ground Clutter Mitigation Scheme consists of two parts: the Radar Echo Classifier (REC) that is partially deployed within the Radar Product Generator (RPG) and the Clutter Mitigation Decision (CMD) that is under development for the Open Radar Data Acquisition (ORDA). The CMD is discussed in Dixon et al. (2005) at this conference. The Radar Echo Classifier (REC) (Kessinger et al, 2003) is a data fusion system that uses fuzzy-logic techniques to estimate the type of scatterer measured by the WSR-88D. The REC consists of three algorithms: the AP Detection Algorithm (APDA) classifies AP ground clutter return, the Precipitation Detection Algorithm (PDA) classifies precipitation regions, and the Sea Clutter Detection Algorithm (SCDA) classifies return from the ocean surface. The APDA is deployed within the RPG. Currently, the APDA is used as a quality control flag for the Enhanced Precipitation Preprocessing (EPRE) hydrological algorithm (O'Bannon and Ding, 2003) to remove ground clutter contamination during construction of the Hybrid Scan Reflectivity (HSR). The HSR is input into the radar-derived rainfall calculation. The PDA has been ported to the RPG Common Operating Development Environment (CODE) and modifications have been made to EPRE. The CODE-version of EPRE now uses outputs from both the APDA and the PDA to better discriminate between precipitation and clutter return. Preliminary results show that, with these modifications, the HSR has higher quality and contains less clutter contamination.