Radar Operations Center

Software Engineering

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 https://www.weather.gov/nl2/).

Software Engineering maintains the Special Product Generator (SPG) software which supplements the NEXRAD WSR-88D product set with products produced from the FAA TDWR base data.

Software Engineering assists with GIS-related projects such as wind farm proposal analyses and radar coverage maps, and blockage data. These help determine impacts to a radar and assist with radar move and low elevation angle studies.

News & Information - Current Software Engineering Activities:

• RDA/RPG Build 22.1:
  • Build 22.1 is primarily a security update but will also include VCP definitions for lower elevations angles at Birmingham, AL (KBMX: 0.4 deg) and Mobile, AL (KMOB: 0.2 deg). Build 22.1 also fixes a problem running local (RDA) VCP 112
  • Build 22.1 has been deployed.
• RDA/RPG Build 23.0:
  • Build 23.0 will allow the MSCF/RPG Operator the ability to release RDA (Local) control to the RPG (Remote). This capability will be password protected.
  • Build 23.0 will include the VCP number in the RDA Status message associated with the Remote VCP Received acknowledgment. The VCP number will be added to the Remote VCP Received acknowledgment message posted to the RPG Status Log.
  • Build 23.0 will include improvements to the Dual Pol Algorithms. The RPG-estimated ISDP (ISDPE) will reset whenever the ISDP value changes at the RDA, the ISDPE will be applied by default and the Vertical Profile of Reflectivity Correction (VPRC) will be on by default.
  • Build 23.0 will fix a bug in the RPG that caused the Power Removed Control (PRC) product from being generated.
  • Build 23.0 will remove the following unused products from the RPG: 1) Layer Composite Reflectivity Maximum (LRM, Code 65), 2) Radar Code Message (RCM, Code 74), 3) Composite Reflectivity Edit for AP (CRE, Code 98), and 4) Clutter Likelihood Doppler (CLV, Code 133).
  • Build 23.0 will add a new Long Pulse VCP 34. VCP 34 will execute in under 9 mins, scan at the same angles as VCP 35 but will be capped at 4.5 deg elevation, and will maintain similar data accuracy as VCP 31.
  • Build 23.0 will include several RPG HCI ported from X/Motif to GTK+. The functionality will be preserved. The look and feel will be slightly different.
  • Build 23.0 is currently in formal Beta Test and is scheduled for full deployment in Fall 2024.
• RDA/RPG Build 24.0:
  • Build 24.0 adds support for IPv6 in addition to the already supported IPv4. Devices that support IPv6 (RPG, RDA, LAN Switches, Routers, Console Servers) will communicate via IPv6. Devices (Power Administrator) and external users (Narrowband Users, and NL2 via LDM) that do not support IPv6 will continue to communicate using IPv4.
  • Build 24.0 includes several enhancements to the 2D Velocity Dealiasing Algorithm (2DVDA): 2DVDA's internal VAD creates a background wind field that is not always representative along discontinuities such as fronts, the leading edge of a QLCS, etc. This can cause velocity dealiasing errors if the algorithm tries to "correct" a solution against the non-representative background wind field, and 2) Turbulence, especially related to high vertical wind shear, can cause dealiasing errors. Reliably detecting turbulence would allow 2DVDA to apply specific dealiasing techniques to handle it, improving overall dealiasing quality.
  • Build 24.0 implements Azimuthal Shear (AzShear) on the RPG (non-operational). Originally intended as an interim product for the New Mesocyclone Detection Algorithm and New Tornado Detection Algorithm (currently in development by NSSL), AzShear went before forecasters as a standalone product during NSSL's Hazardous Weather Testbed. Forecasters appreciated standalone AzShear's utility to expand situational awareness during warning decision-making, and so now the ROC is working with NSSL to incorporate AzShear on the RPG.
  • Build 24.0 adds Long-Term Average Reflectivity (LTAR) input to Hydro Classification Algorithm. The LTAR algorithm and product were added to the RPG in Build 21.0 non-operationally. Data retention and efficiency improvements were added in Builds 22.0 and 23.0. LTAR is effective in identifying areas of persistent ground clutter, and particularly wind farms. build 24 adds LTAR input to the Hydrometeor Classification Algorithm to eliminate erroneous classifications that are often associated with ground clutter. It includes logic that helps retain valid meteorological classifications from stronger echoes, even in the presence of persistent ground clutter.
  • Build 24.0 updates QZdrCal algorithm with cold season modification. The QZdrCal algorithm that estimates ZDR bias from dry aggregate snow was added for evaluation purposes in Build 23.0. That version of the algorithm was designed for the warm season and therefore required the detection of an elevated melting layer. NSSL has developed a cold season version of QZdrCal that does not have the melting layer requirement. This effectively makes QZdrCal an all-season algorithm. Evaluation of its performance for eventual replacement of the legacy dry snow ZDR bias estimator is ongoing.
  • A new tool will be added to RDA Build 24.0 to display the antenna motion as a function of both elevation and azimuth, similar to an existing tool used by the WSR-88D Hotline. This will greatly help the field when the Hotline is working with site technicians in tracking down hardware and pedestal calibrations issues.
  • In Build 24.0, QPE will be smoothed to remove discontinuities. This change focuses on the discontinuity that occurs between rain rate estimators R(A) and R(Z) or R(Z,ZDR). When the Specific Attenuation estimator R(A) is active it can produce rainfall rates that are different from ones used within and above the melting layer. This can cause a sharp boundary in the resulting Quantitative Precipitation Estimate accumulations. A 15 km wide area of weighted mean smoothing is applied between R(A) and R(Z) that blurs out this sharp discontinuity making the QPE accumulations appear more "natural".
  • A fix for a problem with SZ-2 velocities is being implemented in RDA Build 24.0. The update addresses a situation where weather with high reflectivity values did not have corresponding velocities or spectrum widths.
  • In RDA Build 24.0 a fix to the RDA will allow the RPG to gain control of the RDA even when it is under RMS control.
• NL2 Build 14.0:
  • NL2 Build 14.0 contains security updates for RHEL8, restored SPG latency data, updated data decoders to support RDA/RPG Build 23, updated internal IP addresses, restored data feed to top tier client NCIE, and an updated connection to the ROC testbed SPG system. NL2 Build 14.0 was deployed in April, 2024.
• NL2 Build 14.1:
  • NL2 14.1 will include security updates and bug fixes. Bug fixes include: 1) Restoration of reflectivity layer to weather.gov/nl2 maps, 2) Removal of Slidell, LA (KLIX) radar, and 2) fixing some units and scaling of some RDA Adaptation Data fields.
  • Build 14.1 is currently under development. It is scheduled for deployment in November, 2024.