Evaluations of 404 MHz radar wind profiler observations at Okinawa during TCM-90

Abstract

A comparison of made of rawinsonde and radar wind profiler observations recorded in Okinawa during the Tropical Cyclone Motion (TCM) field experiment. the rawinsondes were launched from Naha, 18.5 km south-southwest of the wind profiler at Kadena AB. An examination of wind speed, and u- and v-components shows the two wind measuring systems to be in excellent agreement. Wind speed differences are less than 1.5 m/s and u- and v-component differences are less than 2 m/s surface wind data recorded 1.5 km from the radar wind profiler site at Kadena are used to derive statistical relationships between the wind at the five lowest profiler range gates and the surface sustained wind and gusts. The accuracy of regression equations derived from the surface and upper-level data is compared to that simple wind ratios derived from the same data. The data are also stratified with respect to daytime versus nighttime, and winds having a trajectory from the ocean versus winds with a trajectory from the land. Although the regression equation generally produce a statistically significant smaller prediction error compared to prediction errors from the ratios, the less than 2 m/s improvement in surface wind estimates in not operationally significant.