COSPECTRA OF HEAT AND MOISTURE FLUXES FRO M MEASUREMENTS WITHIN A NEAR-WATER AIR LAYER IN CALM CONDITIONS

The behavior of Eulerian frequency spectra of sensible and latent heat fluxes, as well as of tg-cospectrum, is considered in the inertial su brange above a water surface in calm conditions. This work is based on theoretical and experimental data of previous work [1, 2] and extends an approach that has been developed for frequency autospectra in the limit of free convection to cospectra. In the case of measurements in a stationary reference frame, theoretical relations for free-convectio n frequency cospectra in the inertial subrange are derived on the basi s of dimension considerations and Tennekes' hypothesis of advection of small-scale turbulence by energy-carrying eddies in a shear-free flow (random sweeping hypothesis) [3]. It is shown that the frequency spec tra of heat and moisture fluxes obey a -7/3 law and the cospectrum of temperature and humidity has a slope of -5/3 in the inertial subrange. The theoretical behavior of cospectra in the inertial subrange is com pared with measurements of atmospheric turbulence in a near-water air layer. The measurements were conducted from a stationary platform in a coastal region of the Black Sea in calm conditions.