An instrumentation system for the measurement of atmospheric turbulence

Abstract

A method is described for the detailed multi-point measurement of the turbulent velocity components and temperature in the atmospheric surface layer. The TSI three-dimensional split-film anemometer system is used as sensor and a special designed data-acquisition and data-handling system is used for the sampling, digitizing and storing of the data on digital magnetic tapes. Further processing of the data is performed in a digital computer and programs are developed to allow efficient calculation of the statistical quantities such as, mean values, covariances, power- and cross-spectral density functions. At the present, six anemometer systems have been mounted on the 30-, 50-, 100-, 150-, 200- and 250-foot levels of the 250-foot Meteorological Tower at NASA, Wallops Flight Center. The tower is located at Wallops Island which is one of the barrier islands protecting the so-called “Delmarva” peninsula from the Atlantic Ocean. The island, which consists of a narrow strip of dunes approximately three meters above sea level, is situated in a northeast-southwest direction and is separated from the mainland by a three-mile wide tidal swamp.