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Titel |
A vertical-mode decomposition to investigate low-frequency internal motion across the Atlantic at 26° N |
VerfasserIn |
Z. B. Szuts, J. R. Blundell, M. P. Chidichimo, J. Marotzke |
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 ; 8, no. 3 ; Nr. 8, no. 3 (2012-06-07), S.345-367 |
Datensatznummer |
250005630
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Publikation (Nr.) |
copernicus.org/os-8-345-2012.pdf |
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Zusammenfassung |
Hydrographic data from full-depth moorings maintained by the Rapid/\-MOCHA
project and spanning the Atlantic at 26° N are decomposed into
vertical modes in order to give a dynamical framework for interpreting the
observed fluctuations. Vertical modes at each mooring are fit to pressure
perturbations using a Gauss-Markov inversion. Away from boundaries, the
vertical structure is almost entirely described by the first baroclinic mode,
as confirmed by high correlation between the original signal and
reconstructions using only the first baroclinic mode. These first baroclinic
motions are also highly coherent with altimetric sea surface height (SSH).
Within a Rossby radius (45 km) of the western and eastern boundaries,
however, the decomposition contains significant variance at higher modes, and
there is a corresponding decrease in the agreement between SSH and either the
original signal or the first baroclinic mode reconstruction. Compared to the
full transport signal, transport fluctuations described by the first
baroclinic mode represent <25 km of the variance within 10 km of the
western boundary, in contrast to 60 km at other locations. This decrease
occurs within a Rossby radius of the western boundary. At the eastern
boundary, a linear combination of many baroclinic modes is required to
explain the observed vertical density profile of the seasonal cycle, a result
that is consistent with an oceanic response to wind-forcing being trapped to
the eastern boundary. |
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