WSR-88D Improvements
The WSR-88D (NEXRAD) radars are the weather radars currently in use by the National Weather Service (NWS), Department of Defense (DOD), and the Federal Aviation Administration (FAA). The nationwide network includes over 150 Doppler weather radars, deployed in 1988. The technology for the WSR-88D was developed and tested at NSSL during the 1980's. NSSL engineers working with meteorologists continue to extend the functionality and capabilities of the WSR-88D radar by developing and testing dual-polarization techniques to improve precipitation discrimination, leading to more accurate forecasts and improved airline safety.
- Faster and better signal processing will extend
the usefulness of the current National Weather Service radar network.
Techniques to improve signal processing are tested and evaluated at NSSL before being deployed on NWS systems. Faster, cleaner, better signal processing will lead to earlier detection of hazardous weather features on radar. - Adding dual-polarization
capability to the WSR-88D radar network will improve precipitation discrimination
and estimation and improve hazardous weather detection, extending the functionality
of the current NEXRAD system.
Since different types of precipitation have unique polarimetric signatures, dual-polarized radar will provide forecasters with better information about possible flash flood and winter weather situations. NSSL researchers are developing Polarimetric Radar Applications, including an algorithm to integrate data from surface temperature sensors, numerical weather prediction model thermodynamic output, and dual-polarimetric radar hydrometeor classification algorithm output to produce a surface precipitation type product. Researchers are also studying whether unusual 3-D polarimetric signatures aloft can detect tornadoes. - Implementing range and velocity ambiguity
mitigation techniques in the WSR-88D radar network will result
in an improved ability for the WSR-88D to detect severe weather,
flash floods, winter storms, and provide aviation forecasts.
In
most weather radars, the range and Doppler velocity ambiguity problems
are coupled such that trying to alleviate one of them worsens the other.
Special
techniques
are
necessary to resolve both ambiguities to the levels required for the efficient
observation of severe weather. Efforts in this area are expected to culminate
in superior radar data quality when implemented operationally. The increased
data quality will result in an improved ability for the WSR-88D to detect
severe weather, flash floods, winter storms, and provide aviation forecasts. - An increased ability to identify aviation
weather hazards and to track, classify and identify aircraft will improve
airline safety and help fill gaps in homeland security.
NSSL works with other laboratories to develop FAA warning applications that could mitigate specific weather-related problems. NSSL is also working to develop the capability to track and identify unfriendly aircraft, using WSR-88D data, when the pilot is not responding. Airplane signatures are easy to see and filter in weather radar data. By studying the radar spectral signatures of aircraft, NSSL has learned that weather radar can be used to identify different sizes and even different kinds of airplanes, including large or small aircraft or those with, or without a propeller. This important homeland security benefit will help secure airspace not under the FAA's Air Traffic Control System Command Center.
