 |
| Titel |
Modulation of the Inflow into the Caribbean Sea by North Brazil Current Rings |
| VerfasserIn |
C. Mertens, M. Rhein, M. Walter, K. Kirchner |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250020719
|
|
|
|
|
|
| Zusammenfassung |
| A two–year long record from a triangular mooring array between the Lesser Antilles islands
Tobago, Barbados, and St. Lucia is used to investigate the variability of the inflow into the
Caribbean Sea, the amount of South Atlantic Water (SAW) carried with the inflow, and the
role of North Brazil Currents rings in the observed variability. The data set consists of time
series from temperature/conductivity recorders and current meters at the moorings,
bottom–mounted inverted echo sounders at the Tobago and St. Lucia mooring
positions, supplemented by additional shipboard measurements. The travel time
measurements of the inverted echo sounders and the conductivity/temperature time series are
used for continuous estimation of dynamic height profiles and geostrophic currents
between the surface and 1000 dbar as well as the amount of water from the South
Atlantic.
The observations show a domination of intraseasonal variability between 0 and 15 Sv,
superimposed on the long–term fluctuations. With time scales of one to three months, these
represent the signature of the North Brazil Current rings. During the observational period,
nine transits of rings where observed to interact with the Lesser Antilles Arc, with no marked
seasonality. The arrival of a ring leads to a weakening of the inflow into the Caribbean,
although the rings carry large amounts of SAW into the area. The immediate increase of
the transport towards the end of a ring event suggests a subsequent flow of this
SAW–rich water into the Caribbean. At St. Lucia, rings may also cause a short-term
decrease of SAW content, indicative of an influx of northern hemispheric water and a
blocking situation. The average transport of SAW into the Caribbean during the
observations amounted to 5.5 Sv, with no statistical significant seasonal cycle, but
a small positive trend in SAW fraction as well as in transport of about 15% and
1 Sv, respectively; a corresponding trend in the baroclinic volume transport was not
observed. |
|
|
|
|
|
|