Interaction of Waves, Surface Currents, and Turbulence: the Application of Surface-Following Coordinate Systems

作     者：Jenkins Alastair D 

作者机构：Bjerknes Centre for Climate Research Geophysical Institute Allegaten 70 N-5007 Bergen Norway 

出 版 物：《Journal of Ocean University of China》 (中国海洋大学学报（英文版）)

年 卷 期：2007年第6卷第4期

页      面：319-331页

学科分类：0710[理学-生物学] 0908[农学-水产] 07[理学] 0707[理学-海洋科学] 0815[工学-水利工程] 0824[工学-船舶与海洋工程] 

基　　金：Norges Forskningsråd: 155923/700 

主　　题：wind-wave-current interaction coordinate systems upper-ocean turbulence air-sea exchange of momentum, heat, andmass 

摘      要：Surface waves comprise an important aspect of the interaction between the atmosphere and the ocean, so a dynamically consistent framework for modelling atmosphere-ocean interaction must take account of surface waves, either implicitly or explicitly. In order to calculate the effect of wind forcing on waves and currents, and vice versa, it is necessary to employ a consistent formula- tion of the energy and momentum balance within the airflow, wave field, and water column. It is very advantageous to apply sur- face-following coordinate systems, whereby the steep gradients in mean flow properties near the air-water interface in the cross-interface direction may be resolved over distances which are much smaller than the height of the waves themselves. We may account for the waves explicitly by employing a numerical spectral wave model, and applying a suitable theory of wave–mean flow interaction. If the mean flow is small compared with the wave phase speed, perturbation expansions of the hydrodynamic equations in a Lagrangian or generalized Lagrangian mean framework are useful: for stronger flows, such as for wind blowing over waves, the presence of critical levels where the mean flow velocity is equal to the wave phase speed necessitates the application of more general types of surface-following coordinate system. The interaction of the flow of air and water and associated differences in temperature and the concentration of various substances (such as gas species) gives rise to a complex boundary-layer structure at a wide range of vertical scales, from the sub-millimetre scales of gaseous diffusion, to several tens of metres for the turbulent Ekman layer. The bal- ance of momentum, heat, and mass is also affected significantly by breaking waves, which act to increase the effective area of the surface for mass transfer, and increase turbulent diffusive fluxes via the conversion of wave energy to turbulent kinetic energy.