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| Titel |
The surface thermal signature and air–sea coupling over the Agulhas rings propagating in the South Atlantic Ocean interior |
| VerfasserIn |
J. M. A. C. Souza, B. Chapron, E. Autret |
| 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. 4 ; Nr. 10, no. 4 (2014-07-09), S.633-644 |
| Datensatznummer |
250117036
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| Publikation (Nr.) |
 copernicus.org/os-10-633-2014.pdf |
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| Zusammenfassung |
| The surface signature of Agulhas rings propagating across the South Atlantic
Ocean is observed based on three independent data sets: Advanced Microwave Scanning Radiometer for the Earth Observing System/Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) (TMI/AMSR-E) satellite sea
surface temperature, Argo profiling floats and a merged winds product
derived from scatterometer observations and reanalysis results. A persistent
pattern of cold (negative) sea surface temperature (SST) anomalies in the eddy core, with warm
(positive) anomalies at the boundary, is revealed. This pattern contrasts
with the classical idea of a warm core anticyclone. Taking advantage of a
moving reference frame corresponding to the altimetry-detected Agulhas
rings, modifications of the surface winds by the ocean-induced currents and
SST gradients are evaluated using satellite SST and wind observations. As
obtained, the averaged stationary thermal expression and mean eddy-induced
circulation are coupled to the marine atmospheric boundary layer, leading to
surface wind anomalies. Consequently, an average Ekman pumping associated
with these mean surface wind variations consistently emerges. This
average Ekman pumping is found to explain very well the SST anomaly
signatures of the detected Agulhas rings. Particularly, this mechanism seems
to be the key factor determining that these anticyclonic eddies exhibit
stationary imprints of cold SST anomalies near their core centers. A
residual phase with the maximum sea surface height (SSH) anomaly and wind speed anomaly is found
to the right of the mean wind direction, apparently maintaining a coherent
stationary thermal expression coupled to the marine atmospheric boundary
layer. |
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