The observed generation and breaking of atmospheric internal gravity waves over the ocean

Abstract

Observations are presented for internal gravity waves and their breaking at a height of 23.5 m over the ocean in surface-based inversions which are formed because of the advection of warm air over cold water. The spectral and cospectral analyses of velocity and temperature fluctuations were made to establish the characteristic features of the waves. Flow visualization photographs of smoke released during the breaking of a wave are also presented. Comparison between the turbulent energies present during and after breaking of a wave indicates enormous mixing and dispersion occurring during breaking.

A case of persistent breaking of internal gravity waves in the atmospheric surface layer over the ocean

“…Internal waves have also been observed in the marine surface layer during daytime conditions with stably stratified atmospheric surface layer (SethuRaman, 1977). These waves tend to break because of instability caused by various atmospheric processes and may reform again if conditions are conducive.…”

“…Wind direction was southwesterly at Tiana Beach. The meteorological conditions described above are most conducive to the formation of internal gravity waves in the stably stratified layer immediately above the water surface (SethuRaman, 1976;1977). Vertical profiles of mean potential temperatures over the ocean at three different time periods during the experiment are shown in Figure 3.…”

Wave-like wind fluctuations observed in the stable surface layer over a plant canopy

“…The spectrum of u decreases rapidly above the peak frequency of 0.12 cycle min-i, the steep slope beyond the peak approximating n -4. The slope may be characteristic of the presence of an equilibrium field of breaking waves as discussed by Sethuraman (1977). The spectral density of w was much lower than that of ZJ in the frequency range lower than 1.0 cycle min -' and approached that of u at the highest frequency part of the spectrum.…”

“…These are important in connection with noctural air pollution problems and in studies of the characteristics of gravity waves. Most of these phenomena were observed in the planetary boundary layer or in the surface layer over smooth surfaces such as the ocean and bare soils, e.g., Axford, 1971;Sethuraman, 1977;Zou Leyi and Panofsky, 1983. In this connection, knowledge of the characteristics of nighttime atmospheric turbulence over plant canopies is still quite inadequate, though it is important for understanding the transport and dispersion of heat, CO,, water vapor, spore, insects and other plant diseases.…”

Carbon dioxide fluxes over the atlantic ocean estimated from measurements at Tiana Beach, Long Island, New York

“…Coastal meteorologica studies and diffusion and air-sea interaction experiments are being conducted near this site to study air-sea exchange processes (SethuRaman and Raynor, 1975;SethuRaman, 1976SethuRaman, ,1977SethuRaman, ,1978SethuRaman, 1979a;Raynor et&., 1979). Results of the present preliminary study indicate the feasibility of measuring CO2 concentration gradients and of subsequently estimating CO2 fluxes with reasonable accuracy.…”