Enhancements in 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 Filter Decision System (CFDS) (discussed in a paper by Kessinger and Dixon in this conference) that is under development for the Open Radar Data Acquisition (ORDA).

The Radar Echo Classifier (REC) is a data fusion system that uses fuzzy-logic techniques to estimate the type of scatterer measured by the WSR-88D. For this paper, REC algorithms that will be discussed include the AP Detection Algorithm (APDA) that classifies AP ground clutter return and the Precipitation Detection Algorithm (PDA) that classifies precipitation regions. Within the RPG, the APDA is used as a quality control flag to remove ground clutter contamination during construction of the Hybrid Scan Reflectivity (HSR), which is, in turn, 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 such that outputs from both the APDA and the PDA are used 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. These results will be presented.