 |
| Titel |
Sub-seasonal to seasonal variability of the Atlantic Meridional Overturning Circulation at 26.5N |
| VerfasserIn |
T. O. Kanzow, S. A. Cunningham, W. Johns, J. Hirschi, J. Marotzke, C. Meinen, L. Beal, C. Atkinson, M.-P. Chidichimo, J. Collins |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021630
|
|
|
|
|
|
| Zusammenfassung |
| A 3.5-year timeseries of the strength of the Atlantic meridional overturning circulation (AMOC) at 26.5°N is derived from the addition of four transport components: 1. Gulf Stream transports in Florida Straits inferred from cable measurements; 2. Ekman transports from wind stress measurements; 3. current meter measurements of the shallow and deep western boundary currents and; 4. mid-ocean transports inferred from mooring-based density measurements east of the Bahamas, on both flanks of the mid-Atlantic Ridge and across the African continental slope. The mean AMOC strength is 18.5 Sv, and the standard deviation of 4.9 Sv reflects substantial sub-seasonal and seasonal variability. Fluctuations in Gulf Stream, Ekman and mid-ocean transports are uncorrelated and so their variability translates directly into AMOC variability.
The sub-seasonal variance (periods between 10 and 90 days) of the Ekman transport exceeds that of the Gulf Stream and the mid-ocean transport, dominating fluctuations of the AMOC. However, the seasonal variance (periods > 180 days) of both the Gulf Stream and the mid-ocean transport exceed that of the Ekman transport, dominating seasonal fluctuations of the AMOC. The amplitude of seasonal variations in the AMOC is ±4.2 Sv with maxima in early Autumn and minima in early Spring. The seasonal cycle in upper mid-ocean transport is dominated by a strong seasonal cycle in eastern boundary densities from the surface to 1000 dbar, which is a consequence of seasonal variations of the eastern boundary wind stress curl. |
|
|
|
|
|
|