Etudes et évaluation de processus océaniques par des hiérarchies ...

4.5. MEAN CIRCULATION AND STRUCTURES OF TILTED OCEAN DEEP CONVECTION117
816 J O U R N A L O F P H Y S I C A L O C E A N O G R A P H Y VOLUME 38
tel-00545911, version 1 - 13 Dec 2010
the horizontal velocity field are considered. The similarity
to the wind stress forcing that leads to horizontal
divergence, Ekman pumping, and a large-scale circulation
by Sverdrup balance can be taken further. Gradients
in the heat flux at the ocean surface will lead to
horizontal divergence, leading to vertical velocities and
a large-scale circulation by Sverdrup balance, which is
an effect that is completely neglected when the traditional
approximation is employed.
Furthermore, the vertical shear induced by a tilted
rotation vector will lead to tilted convective chimneys.
This tilt in the chimney structure is likely to play an
important role in the subsequent restratification of the
convective area.
In the present paper we determined the influence of
the horizontal component of the rotation vector on the
convective dynamics. This influence should be reflected
in parameterization schemes of the convective dynamics.
The important, but somehow more controversial,
discussion of the effect of the herein-presented results
on existing parameterization schemes of the convection
process and a construction of an improved parameterization
scheme will be the subject of a forthcoming publication.
The importance of the herein-presented effect
on the ocean global circulation and, more precisely, on
the thermohaline circulation can only be evaluated by
implementing such improved parameterization in an
ocean global circulation model (OGCM).
Acknowledgments. We are grateful to Theo Gerkema,
Yves Morel, Chantal Staquet, Joel Sommeria, and two
anonymous reviewers for their remarks, and to Pagode
du Baron for discussion. The work was funded by
EPSHOM-UJF 00.87.070.00.470.29.25 and EPSHOM-
UJFCA2003/01/CMO. Calculations were performed at
IDRIS (France) within Project 62037. This work is part
of the COUGAR Project funded by ANR-06-JCJC-
0031-01.
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