WAVE MODULATED TURBULENT FIELDS AT THE OCEAN SURFACE AND RELATED AIR-SEA FLUXES

摘要

The upper most layers of the ocean, along with the lower atmospheric boundary layer, play a crucial role in the air-sea fluxes of momentum, heat, and mass, thereby providing important boundary conditions for both the atmosphere and the oceans that control the evolution of weather and climate. In particular, the fluxes of heat and gas rely on exchange processes through the molecular layers, which are usually located within the viscous layer, which is in turn modulated by the waves and the turbulence at the free surface. The understanding of the multiple interactions between, molecular layers, viscous layers, waves and turbulence is therefore paramount for an adequate parameterization of these fluxes. We present evidence of a clear coupling between the surface waves, the surface temperature, and the surface turbulence. The modulation of the surface temperature by the waves lead to a measurable wave-coherent air-sea heat flux. When averaged over time scales longer than the wave period, the coupling between the surface temperature and turbulence leads to a spatial relationship between the temperature, divergence and vorticity fields that is consistent with spatial patterns of Langmuir turbulence. On time scales for which the surface wave field is resolved, we show that the surface turbulence is modulated by the waves in a manner qualitatively consistent with rapid distortion theory.