Wind-profiling doppler radars for tropical atmospheric research

Abstract

The past decade has seen a rapid increase in the use of wind profilers in atmospheric research [Gage, 1990]. Briefly, wind profilers are Doppler radars that observe winds from Doppler shifts of "clear air" atmospheric ech­oes. The atmospheric echoes arise from back­scattering from turbulent irregularities in the radio refractive index of the atmosphere. Wind profilers operate at several VHF and UHF frequencies, notably in the vicinity of 50, 405, and 915 MHz. Since they measure the radial component of the wind, they can be used to monitor vertical as well as horizon­tal motions by using antennas phased to look sequentially in several directions. The wind profilers can be regarded as "all-weather" in­struments, although corrections for fall-speed often have to be made during precipitation. In addition to wind measurements, the wind profilers also yield valuable information on turbulence and in sorne cases on atmospheric stability. Using the latest wind-profiling tech­nology wind can be measured throughout the troposphere and into the lower strato­sphere. The UHF wind profilers are smaller and consequently easier to install. They are especially well suited for high-venical resolu­lion observation oí the lower troposphere. The larger, more powerful VHF wind profil­ers are better suited for observation of the upper troposphere and lower stratosphere. Until recently, most atmospheric research using wind profilers has been carried out with individual radars. With the current widespread acceptance of clear-air radar wind-profiling technology. field programs are increasingly taking advantage of the continuous wind observations available from wind profilers. At the same time, several compa­nies have become active in developing and marketing wind profilers. With the deploy­ment of the 30-station demonstration net­-work of wind profilers in the Central United States, we are on the threshold of a new era in which wind profilers will become an inte­gral pan of the next generation weather-ob­serving system.