General Purpose Weather Surveillance with the Airport Surveillance Radar 11 (ASR-11)

The Federal Aviation Administration (FAA) and Department of Defense (DOD) are currently procuring over 150 new digital airport surveillance radars (ASR-11) to replace many of the nations aging ASR-7 and ASR-8 radars. The primary mission of this new radar is to detect and track aircraft; however, like its predecessor, the ASR-9, it also has a dedicated weather channel. The ASR-11 weather channel is designed to provide air traffic controllers with a National Weather Service (NWS) six level video integrated precipitation (VIP) depiction of weather reflectivity. Although this radar is similar in many respects to the ASR-9, it has two characteristics which make it markedly different. It utilizes a low peak power solid state transmitter and has a short (five pulse) coherent processing interval. Both characteristics pose new challenges to the detection of weather phenomena with this radar and will be discussed in this paper.

There is a growing interest in using FAA and domestic military weather sensing resources to augment the National Oceanic and Atmospheric Administrations (NOAA) weather sensing network. Although air traffic control radars are not designed specifically for weather surveillance, they are still capable of providing extremely useful and timely weather information. This capability has been demonstrated by the ASR-9 wind shear processor (WSP). In this paper, six level ASR-11 VIP output, and timeseries data are used to show the feasibility of using the ASR-11 as a resource for operational weather now-casting and severe weather warning. These data are used to demonstrate the capability of the ASR-11 to provide base weather reflectivity and Doppler velocity data suitable for manual and automated detection of various weather phenomena.

* This work was sponsored by the Federal Aviation Administration under Air Force Contract No. F19628-95-C-0002. Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the U.S. Government. Corresponding author address: James E. Evans, Massachusetts Institute of Technology, Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420-9185; e-mail: paulb@ll.mit.edu