Abstract
Atmospheric fluctuations of carbon dioxide, humidity and temperature were simultaneously measured over the ocean, 255m off the coast line of the Sea of Japan in October, 1986 and 1987, and in August, 1988. The power spectral density of carbon dioxide followed approximately a -5/3 power law in the high frequency ranges. This frequency dependency of carbon dioxide fluctuations is basically similar to those of temperature and humidity. The cospectrum of carbon dioxide and vertical wind velocity had negative components for the whole frequency ranges analyzed, representing a downward transport of carbon dioxide by the turbulent eddies over the ocean. The carbon dioxide flux due to the mean flow showed positive, and its value was about twice that of the turbulent eddy flux. This means that the flux direction of carbon dioxide over the ocean is mainly controlled by the transport direction of fluxes of sensible heat and latent heat. The upward flux of carbon dioxide may occur when the air layer over the ocean is in unstable stratification. It is noted that the total flux of carbon dioxide, which is the summation of the turbulent eddy flux term and the mean flow flux term, increased with increasing fluxes of sensible heat, laten t heat and momentum over the ocean.
