Publications

The ASR-9, the next generation airport surveillance radar, will be deployed by the FAA at over 100 locations throughout the United States. The system includes a weather channel designed to provide ATC personnel with timely and accurate weather reflectivity information as a supplement to normal aircraft information. This report presents results of an assessment of the ASR-9 weather channel performance. Two issues addressed are: (1) whether the ASR-9 weather channel performs according to FAA specifications, and (2) whether the ASR-9 weather channel adequately represents weather reflectivity for ATC purposes. These measurement results are intended to support the FAA in developing the operational use of ASR-9 weather information. Comparisons between data from an ASR-9 in Huntsville, Alabama, recorded during design qualification and testing, and data from two other "reference" radars were used as the basis for the assessment. Several storm cases were analyzed, comprised of stratiform rain, isolated convective storms, squall lines, and cold fronts containing multiple simultaneous convective storms. Results suggest that, with the exception of an apparent 3 dB discrepancy between the weather products of the ASR-9 and the "reference" radars, the ASR-9 weather channel seems to perform according to FAA specifications. Although the ASR-9 products give a reasonable representation of the extent and severity of potentially hazardous weather in Huntsville, the results suggest that the static storm model used to determine beamfill corrections for the ASR-9 should be optimized for the particular climatic region in which an ASR-9 will be operated.