SUhfMARYComposite diagrams of spectra and cospectra were constructed from eight cases of velocity Component and temperature measurements made over the water by an acoustic anemometer. Their universal form is discussed.

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The objective of this study was to investigate the turbulent transfer mechanism near the surface. ‘Direct’ measurements of the turbulent fluxes of momentum, heat, and moisture were made in the atmospheric surface layer 2 m above a grass surface at Ladner, Canada. The spectral correlation coefficients were considered to be a measure of the transfer efficiency as a function of scale size. For momentum transfer the efficiency decreased at all scales as instability increased. It is postulated that this was due to greater amounts of momentum being transferred in bursts of short duration, thus making the spectral correlation coefficient, averaged over sufficient time, smaller. The Ladner results for heat transfer showed that its transfer efficiency increased at all scales when instability increased. The ratio of the transfer efficiency of heat to that of momentum was greater than 1 for most scales, even for near neutral stratifications, and increased to between 2 and 3 for more unstable conditions. The efficiency of moisture transfer was usually smaller than that for heat transfer and was found to depend on the correlation between moisture fluctuations and those of temperature.

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Turbulence data for the International Turbulence Comparison Experiment (ITCE) held at Conargo, N.S.W. (35" 18' S.-145"lO' E.) during October, 1976 are analysed.The standard deviation (s/2)1/2 and covariance w's' measured by a number of instruments and instrument arrays have been compared& assess their field performance and calibration accuracy. Satisfactory agreement, i.e. typically 5% for (s")~/' (except in humidity) and of the order of 20% for n, was achieved, but only after consideration of:(1) Instrumental response at high frequencies.(2) Flow distortion induced by instruments and supporting structures.(3) Spatial separation of instruments used for covariance measurements.(4) Statistical errors associated with single point measurements over a finite averaging time, and with lateral separation of two sensor arrays being compared.