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Radar Product Improvement

The Radar Product Improvement (RPI) Team within the ROC Engineering Branch provides radar functionality and interoperability improvements between radar systems and Advanced Weather Interactive Processing System (AWIPS). RPI is physically located in Silver Spring, MD at the NWS Headquarters to foster coordination and interactions with AWIPS and other NWS enterprise systems and programs.

The primary focus of RPI includes:
  • Maintain awareness of advanced radar technologies; develop ConOps and requirements.
  • Manage tri-agency efforts to research, develop, and implement new radar capabilities and improvements to existing functionality.
  • Maintain Radar Functional Requirements (RFR) document.
  • Implement radar software changes on radar product generation systems and AWIPS.
    • Radar systems include WSR-88D RPG (aka NEXRAD) and TDWR SPG
  • Maintain and distribute Common Operations and Development Environment (CODE) - https://www.weather.gov/code88d/
  • Support WSR-88D, Terminal Doppler Weather Radar (TDWR) Supplemental Product Generator (SPG) and AWIPS testing of operational software releases
    • Provide operationally representative test environments, software versions, radars types, products from live / playback of radar data cases, and subject matter expertise (SMEs).
  • Support ROC Hotline and AWIPS Network Control Facility (NCF) in troubleshooting operational issues.
  • Coordinate changes, monitors performance and troubleshoots radar Level-III product collection and dissemination.
  • Conduct radar-AWIPS-enterprise interoperability testing and operational troubleshooting.
Near-Term WSR-88D Data Quality Improvement Projects
  • Improved SZ-2 censoring thresholds – benefits low elevation SZ-2 cuts (below 1.5 deg)
    • Removes very noisy weak trip velocity estimates
  • Staggered Pulse Repetition Time (SPRT) -- to replace mid elevation Batch cuts (1.8 to 6.4 degrees elevation)
    • No purple haze for the polarimetric variables, and less for Doppler moments
    • Less velocity aliasing with Extended Nyquist velocity up to 116 knots
    • Reflectivity and polarimetric variables with lower variance
  • Clutter Environment Analysis using Adaptive Processing (CLEAN-AP)
    • Clutter detection and filtering required for Staggered PRT
    • Four levels of filter aggressiveness based on clutter strength results in smaller biases to base-data estimates and better clutter suppression
  • Weather Environment Thresholding (WET) -- required/included with CLEAN-AP
    • Reduces clutter filter induced bias when signal is dominated by weather
  • Hybrid Scan Estimator (HSE) – benefits low elevation cuts (below 1.5 deg)
    • Blends polarimetric data from the surveillance split cut with better quality data from the Doppler cut
    • Data is smoother, has less Pink Fringe (i.e., CC > 1.0), and better clutter filter performance
    • Data with low-to-medium SNR and high CC or wide spectrum width is improved most
  • Hybrid Correlation Coefficient (HCC) Estimator – benefits low elevation cuts and weak signal areas on other elevations
    • Reduces amount of Pink Fringe CC data which is common when the number of pulses per radial is small and in areas of low-to-moderate SNR
Near-Term WSR-88D Weather Algorithm Improvement Projects
  • Long Term Average Reflectivity
    • Mitigate persistent contamination from wind turbines, highways, and ground clutter
  • Enhanced Melting Layer Detection Algorithm
    • Enhance detection performance in the situations of low and sloping Melting Layers, and sharp snow / rain boundaries
  • Winter-Surface Hydrometeor classification Algorithm (WsHCA)
    • Add classification of Ice Pellets (IP), Freezing Rain, and Snow/IP mix and determine hydrometeor classification below the beam
  • Quantitative Precipitation Estimation (QPE)
    • Refinements to the R(A) rain estimation approach
    • Mitigation of the bright band contamination
    • QPE in snow and mixed precipitation
Radar / NWS Enterprise Systems Interoperability Projects
  • Improve performance of routine and one-time radar product requests from AWIPS
  • Update radar product suite disseminated on NOAAPORT/SBN to remove low priority products and add super-res reflectivity and velocity products