The UAH-NSSTC/WHNT ARMOR C-band dual-polarimetric radar: A unique collaboration in research, education and technology transfer

Through a unique collaboration between private, university and government sectors, the UAH C-band WSR-74C Doppler radar and supporting computer and communications infrastructure at the National Space Science and Technology Center (NSSTC) were recently upgraded to full dual-polarimetric capabilities. The upgraded radar, named ARMOR (Advanced Radar for Meteorological and Operational Research), is located at Huntsville International Airport under the coverage umbrella of the NASA Northern Alabama Lightning Mapping Array (LMA) and within the northern Alabama Severe Thunderstorm Observations and Research Meteorological network (STORMnet; composed of ARMOR, the UAH-MIPS wind-profiler and radiometer system, the Hytop WSR-88D, the NASA LMA, and the CHARM rain gauge network). In addition to serving as a basic education and research tool at UAH/NSSTC, ARMOR is the only operational dual-polarimetric radar in the world to be used concurrently by broadcast meteorologists (WHNT-TV, Huntsville) in collaboration with researchers and educators at UAH/NSSTC in a direct form of technology transfer to the private and public sectors. ARMOR data are also provided directly to the Huntsville NWS Forecast Office in test mode for warning decision support and training purposes.

ARMOR control, calibration, and data transport are handled via dedicated T-l lines from NSSTC and WHNT-TV. Data can be collected in simultaneous transmit and receive (STAR), and conventional single polarization transmit modes. In addition to standard variables such as radar reflectivity (Z), radial velocity (VR) and spectral width (W), operation in STAR mode facilitates the rapid collection of multi-parameter variables including differential reflectivity (ZDR), differential propagation phase (PHIDP), and correlation coefficient (RHOHV,). Software originally developed for application on the BMRC C-pol radar system by V. N. Bringi and Y. Wang (CSU) has been modified and included into the ARMOR data processing stream to correct for attenuation and differential attenuation, and to provide computation of specific differential phase (KDP). Hydrometeor identification and rain mapping products are then computed in near real-time from the corrected data. Additional software has been developed to facilitate real-time dual-Doppler synthesis via collaboration with the Radar Meteorology Group at CSU. Current plans also call for the development/implementation of single Doppler wind retrieval software for applications in boundary layer meteorology research.

To satisfy both operational and research considerations ARMOR is operated 24 hours per day, 7 days a week in either surveillance, full or sector volume modes. Vertically pointing ZDR calibration scans are also collected on a target of opportunity basis when precipitation conditions permit. Real-time display of data to virtually any UAH Department of Atmospheric Science classroom or weather facility within NSSTC combined with the ability to remotely control the radar enables combined operational and educational use of the ARMOR by NSSTC scientists, operational meteorologists at WHNT and the NWS, and UAH graduate students in courses and research focusing on Remote Sensing, Radar Meteorology, Cloud Physics, Atmospheric Electricity, Radar Engineering and Boundary Layer Meteorology.

Remote sensing via ARMOR, STORMnet, and Satellite (e.g., TRMM, Aqua, GOES etc.) instrumentation coupled with the oscillating tropical and mid-latitude climates of the southeastern U.S., facilitates the study of precipitation, cloud and boundary layer processes (kinematics, microphysics, electrification etc.), over a wide variety of warm and cold season synoptic regimes and cloud system types. Precipitating systems in any of the seasonal regimes can be systematically interrogated and examined for either research or warning decision purposes, and the data fused with that collected by other STORMnet observational platforms. The resultant products provide important added information for warning decision making in both the government and private sectors, while simultaneously providing a robust and steady flow of remote sensing data to researchers and students