Turbulence and turbulent fluxes over the Indian Ocean

Abstract

A C-54Q aircraft equipped with meteorological instruments was flown three times to India to participate in the International Indian Ocean Expedition. Flights were made out of Bombay, Gan, and Aden to observe winds, temperatures, humidities, clouds, radiation, carbon dioxide, tritium, turbulence, and turbulent fluxes of heat, water vapor, momentum and kinetic energy. The present paper reports the values of 405 measurements of the turbulence and turbulent fluxes and interprets them in terms of the monsoon circulation and the effect upon currents and temperatures of the Arabian Sea. Analyses of other data have been reported and interpreted elsewhere. The aircraft turbulence measuring system used was developed earlier by Bunker (1955) (1960). It consisted of a vertical accelerometer, a strain-guage air-speed transducer, a vertical gyro, a platinum wire thermometer and a microwave refractometer for humidity measurements. The data was recorded on a nine-channel oscillograph. A digitizing reader was used to read and punch the data on cards. The turbulent quantities and fluxes were computed and tabulated by machine. The accuracy and limitations of the system are discussed. While much is left to be desired in terms of accuracies and spectral range, the results are meteorologically useful and comparison shows good agreement with other techniques.