Rain Measurement Results Derved from a Two-Polarzation Frequency-Diversity S-band Radar at Wallops Island, Virginia

A dual-polarization radar located at the NASA Wallops Flight Facility, Wallops Island, Virginia is described. This radar operates with a slow polarization switch having a cycle time of 0.7 s and also incorporates a frequency diversity technique to achieve independent sampling over short intervals of time. Rain-rate measurements derived from the dual-polarization radar and low-and high-resolution rain gauges located at a remote site are compared. Average percent differences in rainfall of less than 5 and 16 percent were demonstrated when comparing the dual-polarization radar measurement with the low-and high-resolution rain gauges, respectively. Excellent correlation of the rain rates was in evidence during one rain day. All rain measurement cases examined were limited to only light rain rates (less than 7 mm/h).