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The ROC Software Engineering (ROC/SWE) section provides a variety of support for users of the WSR-88D system. The principle support includes the development, maintenance, enhancement, and problem analysis of software for WSR-88D operational systems. Software Engineers are continuously implementing and testing software modifications that have been requested by NEXRAD users through their respective agencies: the Department of Defense, the Department of Transportation, and the Department of Commerce.  Software Engineering also corrects software defects affecting field operations, and applies security Operating System Updates to maintain our authorization to operate.

Software Engineering's workload is primarily divided between the components of the NEXRAD WSR-88D: the Radar Data Acquisition (RDA), the Radar Products Generator (RPG) and the Master System Control Function (MSCF).  The MSCF hosts operator user interfaces to the RDA and RPG, providing command, control and status monitoring for the WSR-88D system. 

Software Engineering maintains the Archive Level 2 monitoring and radar data distribution software, also known as National Level 2 (NL2).   The NL2 project is responsible for ensuring valuable WSR-88D radar data is reliably distributed to the Level 2 user community in real-time.  Software Engineering also maintains a Level 2 status page showing Level 2 statistics including radar status, operating mode, and data distribution latency values for all WSR-88D and TDWR/SPG network sites. (see

Software Engineering conducts wind farm proposal analyses.  In collaboration with wind farm developers, Software Engineering determines whether proposed wind farm turbines penetrate the Radar Line Of Site (RLOS) and if so, to what degree.  Significant RLOS penetration negatively impacts radar data quality, including the reliable estimation of rainfall rates and accumulations.

Software Engineering maintains radar coverage maps to show NEXRAD Volume Coverage Pattern (VCP) 12 bottom-of-beam and TDWR VCP 80 bottom-of-beam coverage at 3,000, 6,000, and 10,000 feet above ground level. Radar coverage maps and beam blockage data are also generated to support radar moves and low elevation angle studies.

News & Information:


  • RDA/RPG Build 20.0:

    RDA/RPG Build 20 deployment completed December, 2020.

    Build 20 includes several enhancements to support the FAA. This includes the implementation of the  Chaff Detection Algorithm (CDA), and the upgrade to the Super-Resolution Data-Quality Edited Reflectivity Algorithm and Product (SRQ). The implementation of the CDA satisfies an FAA requirement for providing display of both weather and chaff. The CDA algorithm output will be used by downstream FAA algorithms/products to provide chaff information to the FAA. The NextGen Weather Processor will access the CDA output (via the Super Resolution Quality Edited Reflectivity) to create “sliding” or “virtual” VIL and Echo Tops “volume” products after each new elevation scan, analogous to the High Resolution VIL and High Resolution Echo Tops products, respectively. The SRQ algorithm and product provide the FAA NextGen Weather Processor with data-quality-edited super resolution reflectivity tilt data. This upgrade will improve quality and provide chaff information not in the current fielded version. Implementation of this CCR will help fulfill an FAA requirement stating that both weather and chaff be presented to the user.

    Build 20 improves the radial to radial continuity of the Specific Attenuation rainfall rate relationship within the Quantitative Precipitation (QPE) Algorithm. The change substantially reduces the appearance of radial to radial discontinuities (“spokes") and speckle artifacts that appear in light and sometimes heavy precipitation events. These discontinuities are partially caused by radial to radial variance within the Dual Pol Differential Phase (PHI) field but can also appear when there are radial by radial differences in the rainfall rate relationship used.

    Build 20 improves the accuracy of ZDR bias estimates in light rain. Out of three external target methods used to estimate the existence of a ZDR Bias at a site, Light Rain estimates had more bias and variance than results from Dry Snow or Bragg Scatter. An improved method of using Light Rain targets reduces the chance for high bias and variability by more accurately selecting target bins and environments to reduce contamination from convection or non-liquid particles. Results show Light Rain estimates are closer in value to the Dry Snow and Bragg Scatter estimates from a site, thus increasing confidence in the reported value and overall existence of ZDR Bias at a site.  

    RDA Build 20 includes many improvements to the System Test Software (STS). The STS is used by field technicians for radar calibration and hardware performance troubleshooting. A new RDA alarm was added when the Elevation Bias Correction (EBC) applied the maximum correction. 

    RDA/RPG Build 20 also includes many software defect corrections, minor enhancements and Operating System (OS) security patches

  • RDA/RPG Build 20.1:
    RDA/RPG Build 20.1 is primarily an RDA/RPG OS security patch release but will contain a software defect correction related to AWIPS command/control when Manual PRF Selection is enabled at the RPG. This change will prevent the user’s manual PRF selections from being overridden when the AWIPS user issues a Volume Coverage Pattern (VCP) restart, or AVSET/SAILS/MRLE changes.  

    RDA/RPG  Build 20.1 deployment is scheduled for Winter, 2021

  • RDA/RPG Build 21.0:
    RDA Build 21.0 removes the Coherency-Based Thresholding (CBT) Enable/Disable Button from the RDA HCI. Prior to Build 21.0, CBT could be disabled as there were potential data quality issues running SZ2 VCPs with CBT enabled. Recent changes to the SZ2 algorithm make the need for CBT to be manually disabled unnecessary. CBT will be enabled by default all the time starting with Build 21. 

    RPG Build 21 changes the Velocity Measurement Increment (VMI) at RPG instead of at the RDA. The VMI can be set to 0.5  m/s or 1.0 m/s by the RPG operator.   The 1.0 m/s resolution is recommended during tropical weather events when the velocities can be quite large.   Any changes to the VMI would change the velocity data in the Level 2 stream as the velocity increment was applied at the RDA.  With this change, the VMI will be changed to the RPG instead of the RDA.  Consequently the Level 2 velocity data will always be 0.5 resolution.  

    In Build 21, the AWIPS operator will also be able to change the VMI using the AWIPS Command/Control capability. 

    Starting in Build 21.0, the RPG will report ZDR bias information in the Shift Change Checklist (SCC) product.  The ZDR Bias Weighted Mean value derived from external targets (Snow, Bragg and Light Rain) can be used for monitoring by field personnel.   A daily weighted mean value, matching the Data Quality Dashboard on the RPG HCI, will be reported.  The value will be updated once a day on the first volume for that date (immediately on or following a 00:00 UTC timestamp).  The SCC product is distributed to AWIPS once an hour at the top of the hour.  

    Build 21 adds the Rain Rate Classification (RRC) algorithm/product. This product provides the user information on which rain rate relationships were used to derive the rain rate estimates.   Included in this change is the removal of the edit capability for the Ice Crystal (IC) Multiplier in Dual Pol Precipitation adaptation data.   The IC multiplier will be set to the same value as the Dry Snow (DS) Multiplier.

    Build 21 adds a Restart Failed Tasks button to the RPG Control HCI GUI. This button can be used to restart failed RPG tasks without the need to restart the entire RPG. 

    Build 21 removes 4-bit (16 data level) Reflectivity products 19 and 20, and the 4-bit Velocity product 27.   Products 19 and 20 are still generated at the RPG to support the Clutter Censor Zone Editor and PRF Editor, but will not be made available to external users.

    RDA/RPG Build 21 also includes numerous bug fixes, minor enhancements, and OS patches to improve security.

    RDA/RPG Build 21.0 deployment scheduled for Summer 2022.

  • NL2 Build 11.0:
    NL2 Build 11.0 was deployed May 6th, 2021. This build included updated decoders to display RPG build 20 data on and to remove code for software builds no longer in the field.  The NL2 web pages at were also updated to include backup comms monitoring and NTP status on the NEXRAD Map view. The NL2 servers were configured as time servers to provide a single authoritative time source for the RPG, SPG and NPN. Security patches and updates were also included. Improvements in the software build script were made to make it more user friendly by finding errors in files and paths entered on the command line.

  • NL2 Build 11.1:
    NL2 Build 11.1 was primarily an OS security patch update.  NL2 Build 11.1 was deployed October 27th, 2021.

  • NL2 Build 12:0:
    NL2 Build 12.0 is scheduled for deployment in late March 2022.