21st International Conference on Interactive Information Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology


The AP ground clutter mitigation scheme for the WSR-88D

Cathy Kessinger, NCAR, Boulder, CO; and S. Ellis, J. Van Andel, J. Yee, and J. Hubbert

Deployment of the AP Clutter Mitigation Scheme is ongoing within the Open Radar Product Generation (ORPG) of the Weather Surveillance Radar-1988 Doppler (WSR-88D). Once fully deployed, this scheme will improve the quality of the radar base data by identification and removal of ground clutter echoes produced under anomalous propagation (AP) conditions. With the upcoming deployment of the Open Radar Data Acquisition (ORDA), the AP Clutter Mitigation Scheme is modified to consist of two parts: the Radar Echo Classifier (REC) and the Reflectivity Compensation Scheme (Z-Comp). Clutter filter specification and control once were a part of the AP Clutter Mitigation Scheme but the spectral domain clutter filter processing that is available in the ORDA is an improvement over techniques possible with the ORPG. Further, the REC will be adapted to the ORDA environment to facilitate the identification of ground clutter and precipitation echoes within the spectral domain to disable clutter filters when the radar return is from precipitation and the radial velocity is near zero m/s. This new, spectral-domain ORDA REC is under development now and should result in improved moment estimates.

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. 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 was deployed in ORPG Build 2. For ORPG Build 5, the APDA is used as a quality control flag for the Enhanced Precipitation Preprocessing (EPRE) hydrological algorithm to remove ground clutter contamination.

The Reflectivity Compensation Scheme (Z-Comp) uses a Gaussian approximation for precipitation spectra and a simulated WSR-88D clutter filter to estimate the correction necessary to offset the clutter-filter-induced bias in the reflectivity. Output from the REC PDA and APDA determine where the Z-Comp method is applied such that only regions of precipitation are compensated. For Build 8, the Z-Comp and REC PDA will be deployed in the ORPG. These fields, along with the REC APDA, are planned to be used by the EPRE to produce better radar-derived rainfall estimates.

Results from the recent North American Monsoon Experiment (NAME) held near Mazatlan, Mexico will be shown using data from the NCAR S-Pol radar. Upgrades to the ORPG APDA will also be discussed.

extended abstract  Extended Abstract (856K)

Poster Session 1, IIPS Poster Session I
Monday, 10 January 2005, 2:30 PM-4:00 PM

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