Field Tests of a Sonic Anemometer-Thermometer1

Abstract

A Sonic Anemometer-Thermometer system for use at an operational airfield is described. The system provides data on net large-scale surface air movements (wind) and speed of sound (or virtual air temperature) by means of acoustic signals. The measurements are made directly over an operational runway, thus providing data from the actual area of interest. Field tests have shown that the temperature and winds measured over the runway are consistently different from those measured at the usual instrument-shelter locations. Surface wind shifts may occur at one place as much as half an hour prior to shifts at the other location, with dangerous operational conditions resulting. Wind velocities and temperatures measured over the runway by the sonic anemometer-thermometer are more representative of runway operational conditions than the measurements made by any combination of conventional instruments placed off the runway.