Some Aspects of Turbulence Role in Oceanic Currents - Selected Topics of Computational and Experimental Fluid Mechanics - page 174

Some Aspects of Turbulence Role
in Oceanic Currents

A. Ruiz Angulo

Abstract This manuscript is intended to review some of the methods used to
estimate one of themost useful parameters inOceanModeling: the diapycnal diffusiv-
ity. Specifically it focus on simultaneous measurements carried out at two different
locations in the deep ocean. The techniques reviewed here to estimate diapycnal
mixing in the ocean interior are: tracer-release experiments, microstructure direct
measurements and fine-structure estimates based on LADCP CTD data. There are

only few data sets in the world that have simultaneous measurements of the three
techniques mentioned above. The importance of the lack of spatial and temporal
estimates of the turbulent mixing parameters and the implication of those parameters
on modeling the Global Circulation are also reviewed.

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1 Introduction

The Global Ocean Circulation is a vastly studied topic and yet several aspects remain
uncovered. The big picture of the General Ocean Circulation is captured by the
relatively recent concept of Thermohaline Circulation or Conveyor Belt (Gordon
1986 ; Broecker 1987b ; Rahmstorf 2003 ). From this point of view, the main oceanic
currents follow large scale trajectories; however, those main streams derivate into a
very large number of smaller circulation trajectories. Some of those small deviations
from the big picture are completely unpredictable. Thus, despite the fact that the large
picture of the Ocean Circulation can be captured on a closed and relatively stable
system, to complete the picture it is necessary to include the small scales along with
their turbulent nature.
The resolution of the General Circulation Models (GCM) does not, until now,
resolve turbulent mixing (Baumert and Peters 2009 ); therefore, the governing equa-
tions used by the models need to parametrize the turbulence. This manuscript mainly