The National Weather Service Doppler Radar in Corpus Christi will be turned off from March 29 through April 12 for a major upgrade. However backup coverage will be provided by radars in Brownsville, Del Rio, New Braunfels, and Houston.
The most significant upgrade to the National Weather Service (NWS) network of Doppler radars [WSR-88D] is in the latter stages of completion. Over 120 of the 155 Doppler radars nationwide have already been upgraded, and Corpus Christi’s upgrade is coming soon. This upgrade incorporates a new technology called dual-polarization, or dual-pol. The upgrade for the Corpus Christi Doppler radar is scheduled to occur during the first two weeks of April 2013 at the Corpus Christi International Airport. This new technology will result in 14 new radar products to the suite of radar data already available to NWS forecasters. These tools will assist forecasters in the warning and forecast process. This new technology and data primarily will help forecasters improve rainfall estimates along with identifying the type of precipitation that is falling.
We strongly encourage all users of these new products to complete a series of online training modules that were recorded by the Warning Decision Training Branch (WDTB). Modules are available for non-NWS meteorologists and non-meteorologists through this website. Additional information on dual-pol can be accessed from the National Severe Storms Laboratory website.
For more information about this outage and upgrade, please contact Warning Coordination Meteorologist, John Metz at 361-299-1353 or e-mail John.Metz@noaa.gov.
The current 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 such as cloud and precipitation droplets. Dual-polarimetric radar transmits and receives pulses in both a horizontal and vertical orientation. Therefore, the radar measures both the horizontal and vertical dimensions of targets. Since the radar receives energy from horizontal and vertical pulses, we can obtain better estimates of the size, shape, and variety of targets. It is expected that this will result in significant improvements in the estimation of precipitation rates, the ability to discriminate between precipitation types (hail vs. rain), and the identification of non-meteorological returns.
Some of the fundamental variables measured by polarimetric radars, and a short description of each, are listed below:
Dual-Pol will not improve tornado warning lead times but will have the ability to identify debris from a damaging tornado, providing confirmation on the location and danger of an ongoing tornado, even when storm spotter reports are not possible due to night time or low visibility near the tornado
The base radar products that have been available to users are base reflectivity, base velocity, and spectrum width. Three new base products will be available after the dual-pol upgrade, including 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.
Images are courtesy of the Warning Decision Training Branch.