WSR-88D Columbus AFB (KGWX)
Upgrade to Dual Polarization

The exciting dual-polarization radar upgrade to the KGWX WSR-88D begins this Friday!  Because of the dual pol upgrade to KBMX at the beginning of 2012, we have already seen the benefits of dual polarization, including the abililty to see tornadic debris.  We strongly encourage users of our current radar information to refamiliarize themselves with these new products through a series of online training modules provided by the Warning Decision Training Branch (WDTB). Modules are available for non-NWS meteorologists and non-meteorologists here.

KGWX will be down for 5-7 days as technicians upgrade the radar.  In the meantime, NWS meteorologists will utilize the numerous other radars around Alabama, Mississippi and West Tennesse, including KDGX in Jackson, KNQA in Memphis, KBMX in Birmingham and KHTX in northern Alabama.

The dual-polarization upgrade to the KMXX WSR-88D at Maxwell Air Force Base, AL is anticipated to begin February 18, 2013. More information on the deployment and availability of the radar data will be provided as this upgrade approaches.

What is Dual-Pol?

The current WSR-88D Doppler radars transmit and receive pulses of radio waves in a horizontal orientation. As a result, the radar only measures the horizontal dimensions of targets (e.g. cloud and precipitation droplets). Dual-polarimetric radar transmits and receives pulses in both a horizontal and vertical orientation. As a result, the returning frequencies provide measurements of the horizontal and vertical dimensions of targets, supplying forecasters with better estimates of the size, shape, and variety of targets.

 Current NWS doppler radar
 Dual-pol radar
Current NWS doppler radar Dual-polarimetric radar

Benefits of Dual-Pol
  • Improved accuracy of precipitation estimates, leading to better flash flood detection
  • Ability to discern between heavy rain, hail, snow, and sleet
  • Improved detection of non-meteorological echoes (e.g. ground clutter, chaff, anomalous propagation, birds, and tornado debris)
  • Detection of aircraft icing conditions
  • Identification of the melting layer (e.g. bright band)
Dual-Pol Products & Applications

The base radar products that have been available to users are base reflectivity, base velocity, and spectrum width. After the Dual-Pol upgrade, three new base products will be available: differential reflectivity (ZDR), correlation coefficient (CC), and specific differential phase (KDP). In addition to these three new base products, there will be several derived products. These include a melting layer (ML) product, a hydrometeor classification algorithm (HCA) product, and eight new precipitation products. Mouse-over the labels below to view examples of four of these new products. Images courtesy of the Warning Decision Training Branch.


Differential Reflectivity


Training & Additional Information

Radar images courtesy of WDTB

Some of the web content courtesy of NWS AMA & NWS FFC

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