Publication Date:
2022-05-26
Description:
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Progress In Oceanography 82 (2009): 191-223, doi:10.1016/j.pocean.2009.07.004.
Description:
In conjunction with the GLOBEC (Global Ocean Ecosystems Dynamics) program,
measurements of moored currents, temperature and salinity were made during 1994-1999 at
locations in 76 m of water along the Southern Flank of Georges Bank and at the Northeastern
Peak. The measurements concentrate on the biologically crucial winter and spring periods, and
coverage during the fall is usually poorer.
Current time series were completely dominated by the semidiurnal M2 tidal component, while
other tidal species (including the diurnal K1 component) were also important. There was a
substantial wind-driven component of the flow, which was linked, especially during the summer,
to regional–scale response patterns. The current response at the Northeast Peak was especially
strong in the 3-4 day period band, and this response is shown to be related to an amplifying
topographic wave propagating eastward along the northern flank. Monthly mean flows on the
southern flank are southwestward throughout the year, but strongest in the summertime. The
observed tendency for summertime maximum along-bank flow to occur at depth is rationalized
in terms of density gradients associated with a near-surface freshwater tongue wrapping around
the Bank.
Temperature and salinity time series demonstrate the presence, altogether about 25% of the time,
of a number of intruding water masses. These intrusions could last anywhere from a couple days
up to about a month. The sources of these intrusions can be broadly classified as the Scotian
Shelf (especially during the winter), the Western Gulf of Maine (especially during the summer),
and the deeper ocean south of Georges Bank (throughout the year). On longer time scales, the
temperature variability is dominated by seasonal temperature changes. During the spring and
summer, these changes are balanced by local heating or cooling, but wintertime cooling involves
advective lateral transports as well. Salinity variations have weak, if any, seasonal variability, but
are dominated by interannual changes that are related to regional- or basin-scale changes.
All considered, Georges Bank temperature and salinity characteristics are found to be highly
dependent on the surrounding waters, but many questions remain, especially in terms of whether
intrusive events leave a sustained impact on Bank waters.
Description:
This work took place as part of the GLOBEC Northwest Atlantic/Georges Bank field project,
and was sponsored through NSF Biological Oceanography grants OCE- 80644500 and OCE-
80644501.
Keywords:
Wind-driven circulation
;
Buoyancy-driven circulation
;
Stratification
;
Seasonal/interannual variability
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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