Summary of the Radar Calibration Workshop

Radar calibration is a crucial step in producing high quality data for the quantitative use of weather radar. While receiver calibration is commonplace, a complete end to end calibration is difficult to achieve in operations. The latter includes: antenna pointing accuracy and precision, antenna gain, radome loss, waveguide loss, matched filter receiver losses and so on. Also, the performance and failure modes of the various radar components need to be monitored, detected and corrected. Techniques have been described in the literature and in folklore to these issues but in actual practice, the reported successes are not always achieved. Progress in radar hardware technology such as the development of the digital receiver has blurred the lines of traditional calibration boundaries. Polarization and wind profiler radars have their own calibration issues distinct from single polarization Doppler radars.

Radar calibration is distinct from radar validation. The former is generally thought to deal only with the radar hardware and the latter deals with rainfall or other forms of comparisons and involves the physics of precipitation. However, in practice, the distinction is blurred as end users often use raingauge comparisons as the benchmark of radar calibration.

The paper will provide a short summary of the presentations and discussions from the Radar Calibration Workshop (13-14 January 2001). This workshop was organized by the American Meteorological Society's Committee on Radar Meteorology and brought together a wide ranging group of experts to primarily discuss the issues of radar calibration but touched also on the issue of radar validation.