Ocean Mixing: From Stratified Turbulence to Large-Scale Meridional Overturning Circulation

Session ID#: 9674

Session Description:
Turbulent mixing produced by breaking internal waves plays a primary role in the climate through exerting a control upon the upwelling of deep dense waters formed at high latitudes, thereby driving the global ocean overturning circulation. Mixing is facilitated by turbulence induced by breaking internal waves occurring at scales too small to be resolved in climate models, invoking the need for parameterization. Conventional parameterizations were developed decades ago and verified through laboratory and numerical experiments conducted at parameter regimes far from those of the real ocean. Recent numerical simulations and observations have allowed us to revisit the basic assumptions behind parameterization schemes to learn that some of them are poorly justified, leading to inaccurate mixing estimates. This tutorial will provide (I) an overview of the fluid dynamics theory of wave-breaking-induced turbulence and its parameterization, (II) a discussion of recent progress due to recent high resolution numerical simulations and observations, (III) a discussion on the implications of the new findings for the ocean meridional overturning circulation (MOC). The tutorial will walk the audience through the steps required to translate information obtained at the microscale concerning small scale mixing to macroscale effects on the MOC.
Moderator:  Karen L Casciotti, Stanford University, Earth System Science, Stanford, United States
Primary Presenter:  Ali Mashayek, Massachusetts Institute of Technology, Cambridge, MA, United States
Presenter:  Colm-cille Patrick Caulfield, University of Cambridge, BP Institute/Department of Applied Mathematics and Theoretical Physics, Cambridge, United Kingdom
Index Terms:

4524 Fine structure and microstructure [OCEANOGRAPHY: PHYSICAL]
4532 General circulation [OCEANOGRAPHY: PHYSICAL]
4544 Internal and inertial waves [OCEANOGRAPHY: PHYSICAL]
4568 Turbulence, diffusion, and mixing processes [OCEANOGRAPHY: PHYSICAL]
  • A - Air-sea Interactions and Upper Ocean Processes
  • EC - Estuarine and Coastal
  • PO - Physical Oceanography/Ocean Circulation
  • TP - Turbulent Processes