Publication Date:
2022-05-26
Description:
Author Note: The material of this report was presented ten years ago at a
symposium, but on account of its speculative nature, remained unpublished.
Several colleagues were, however, kind enough to quote it on occasion
(e.g. Garrett, 1982) and some have requested copies. In order to make it
more readily available, it has now been re-issued as a WHOI report. Paper presented at the Canadian Committee of Oceanography Symposium, Burlington,
Ontario, May 4, 1972.
Description:
A first order, linear analysis of thermocline
upwelling shows that a quasigeostrophic baroclinic
jet accompanies the upwelling. The secondary circulation
induced in such a flow field in a
meridional plane by turbulent friction is investigated.
A double Ekman layer is found to form at
the thermocline, of a few meters in thickness.
The suction of this Ekman layer destroys the primary
flow by the "spin-up" mechanism in a period of which
the order of magnitude is tentatively estimated at
100 hrs. Thus the primary flow must be reestablished
by successive, reasonably frequent wind-stress
impulses to maintain a quasi-stationary upwelling.
The lower side Ekman layer on the thermocline
is fed from a free shear layer (turbulent "Stewartson
layer") underneath the free surface -thermocline
intersection, which thus becomes an upwelling zone.
The width of the turbulent Stewartson layer is
estimated to be the velocity difference divided by
the Coriolis parameter, i.e. typically of the order
of 1 km.
Description:
Prepared for NOAA, Great Lakes Environmental Research
Laboratory, Ann Arbor, Michigan.
Keywords:
Upwelling
;
Thermoclines
Repository Name:
Woods Hole Open Access Server
Type:
Technical Report
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