Observations of the Wind Field in Tornadoes, Funnel Clouds, and Wall Clouds with a Portable Doppler Radar

Abstract

A severe-storm intercept field program was held in Oklahoma and nearby parts of Texas during the 1987?38 spring seasons. The purpose of the experiment was to use, for the first time, a low-power, portable, continuous-wave (CW), 3-cm Doppler radar to obtain wind spectra in tornadoes from a distance of less than 10 km. We discuss measurements of spectra we recorded in a tornado, a funnel cloud, and two wall clouds. Photographic documentation is also given to aid in the interpretation of our data. Wind speeds as high as 60 m s?1 were measured in the tornado. It was found that deploying the portable Doppler radar from a storm-intercept vehicle may increase substantially the number of measurements of wind speeds in tornadoes. The radar has recently been modified so that it has frequency modulation (FM) capability, and hence can obtain wind spectra within range bins. A plan is presented for using the radar to find the source of vorticity in tornadoes.