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| Titel |
Basin-wide response of the North Atlantic Meridional Overturning Circulation to wind stress forcing |
| VerfasserIn |
S. Elipot, E. Frajka-Williams, C. Hughes, S. Olhede, M. Lankhorst |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250063884
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| Zusammenfassung |
| The dynamics and response to wind stress forcing of the North Atlantic Meridional
Overturning Circulation (AMOC) are investigated from an observational standpoint, using
four time series of overturning transports below 1000 m spanning 3.7 years. These time series
are derived from four moored arrays located on the western boundary of the North Atlantic
basin: the RAPID WAVE array (42.5°N), the Woods Hole Oceanographic Institution Line W
array (39°N), the RAPID MOC array (26.5°N), and the MOVE array (16°N). Mode
decomposition of the analytic cross-covariance between these transport time series and
scaterrometer wind stress over the North Atlantic suggests that basin-scale changes in the
atmospheric forcing significantly affect the AMOC on relatively short time scales. First, the
phasing of the transport time series at semi-annual and annual time scales is shown to be
statistically linked to basin-wide seasonal patterns of wind stress and wind stress curl.
This predominant mode of covariability between overturning transports and wind
stress is interpreted in terms of rapid basin-scale adjustments in the form of two
counter-rotating meridional overturning Ekman cells centered on the tropics and the
subtropical gyre. A second mode of co-variability is found which is associated
with anomalous patterns of wind stress and wind stress curl correlated with the
North Atlantic Oscillation. This mode acts to modulate the strength of the horizontal
gyre circulations, and to reinforce and weaken at times a basin-wide overturning
cell. |
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