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| Titel |
Flow dynamics around downwelling submarine canyons |
| VerfasserIn |
J. M. Spurgin, S. E. Allen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 10, no. 5 ; Nr. 10, no. 5 (2014-10-14), S.799-819 |
| Datensatznummer |
250117068
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| Publikation (Nr.) |
 copernicus.org/os-10-799-2014.pdf |
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| Zusammenfassung |
| Flow dynamics around a downwelling submarine canyon were
analysed
with the Massachusetts Institute of Technology general circulation
model. Blanes Canyon (northwestern Mediterranean) was used for
topographic and initial forcing conditions. Fourteen scenarios were
modelled with varying forcing conditions. Rossby and Burger
numbers were used to determine the significance of Coriolis
acceleration and stratification (respectively) and their impacts on
flow dynamics. A new non-dimensional parameter (χ) was
introduced to determine the significance of vertical variations in
stratification. Some simulations do see brief periods of upwards
displacement of water during the 10-day model period; however, the
presence of the submarine canyon is found to enhance downwards
advection of density in all model scenarios. High Burger numbers
lead to negative vorticity and a trapped anticyclonic eddy within
the canyon, as well as an increased density anomaly. Low Burger
numbers lead to positive vorticity, cyclonic circulation, and weaker
density anomalies. Vertical variations in stratification affect
zonal jet placement. Under the same forcing conditions, the zonal
jet is pushed offshore in more uniformly stratified
domains. The offshore jet location generates upwards density advection
away from the canyon, while onshore jets generate downwards density
advection everywhere within the model domain. Increasing Rossby
values across the canyon axis, as well as decreasing Burger values,
increase negative vertical flux at shelf break depth
(150 m). Increasing Rossby numbers lead to stronger
downwards advection of a passive tracer (nitrate), as well as
stronger vorticity within the canyon. Results from previous studies
are explained within this new dynamic framework. |
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