NSFGEO-NERC: Stimulated Loss of Balance

点击翻译按钮获取中文摘要

Recent results obtained by the PIs show that the advection and refraction of near-inertial waves (NIWs) by mesoscale flow is necessarily accompanied by a transfer of energy from the mesoscale to NIWs: the presence of externally forced NIWs stimulates a loss of energy from the geostrophically and hydrostatically balanced component of the flow. This process, stimulated loss of balance (SLOB), should be contrasted with the much more studied and weaker process known as spontaneous loss of balance. The spontaneous version occurs at order one Rossby number and without externally forced waves. But the stimulated version is active even at small Rossby number and hence, we hypothesize, throughout the ocean. The main objectives of this proposal are to assess and develop the hypothesis that SLOB plays a major role in the mesoscale energy budget, and to investigate SLOB by components of the internal wave spectrum other than NIWs, particularly the internal tide (IT). This will be achieved by the development of new, phase-averaged models coupling the dynamics of internal waves with that of the balanced mesoscale flow, and through numerical solution of both these models and of the three-dimensional Boussinesq equations. The outcome will be a quantitative understanding of the role played by SLOB in the ocean energy budget.