ON THE MINIMUM USEFUL ELEVATION ANGLE FOR WEATHER SURVEILLANCE RADAR SCANS

The antenna beam pattern for low elevation angles is examined in relat ion to the radar horizon to assess the impact of base-scan elevation a ngle on sensitivity to near-horizon weather features, as well as its e ffect on reflectivity measurements and ground clutter. The results fro m a simple model neglecting details of surface characteristics and mul tipath propagation suggest that a base elevation angle of about 0.3 be amwidth above the horizon would yield near-optimum sensitivity with ac ceptable degradation in reflectivity observations and ground clutter.