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| Titel |
Heat fluxes in the Drake Passage |
| VerfasserIn |
Ramiro Ferrari, Christine Provost, Young Hyang Park, Nathalie Sennéchael, Hela Sekma, Gilles Garric |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087644
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| Publikation (Nr.) |
 EGU/EGU2014-1703.pdf |
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| Zusammenfassung |
| In contrast to a long-standing belief, observations in the Antarctic Circumpolar Current
(ACC) show that mean velocity vectors rotate with depth, thus suggesting a possible
importance of the time-mean flow for the local poleward heat transport [Sekma et al.,
2012].
The respective contributions of the eddy and mean flows to the heat flux across the ACC
in the Drake Passage are investigated using in situ measurements collected during the
DRAKE 2006-9 project (from January 2006 to March 2009) and available observations from
the historical DRAKE 79 experiment.
DRAKE 2006-9 current meter records, obtained from a current meter array deployed on
the eastern side of the Shackleton Fracture Zone (SFZ), revealed a vertical consistency of the
velocity and temperature variations. However, the rotation of the mean velocity vector with
depth indicated consistent downwelling through the entire water column practically all along
the mooring line.
In situ temperature and velocity time series from the DRAKE 2006-9 project were
combined with the year-long historical DRAKE 79 experiment data set in order to analyse the
eddy and mean flow contributions to the meridional heat flux across in the Drake Passage.
Estimated cross-stream heat fluxes caused by the rotation of the mean flow with
depth were found to be at least an order of magnitude larger than eddy heat ?uxes.
Equatorward heat fluxes caused by the mean flow found downstream the SFZ were
in agreement with the general downwelling observed along the DRAKE 2006-9
project mooring array. Upstream the SFZ, however, the distribution of equatorward
and poleward fluxes was puzzling. This distribution was analyzed using model
outputs.
Heat flux due to the mean ?ow estimated from the high resolution model outputs were
similar to those obtained from in situ data and exhibited small spatial scales. The rough
topography in Drake Passage likely promotes associated small spatial scales of vertical
velocities and heat fluxes. The model-estimated heat flux due to the mean flow across the
Southern ACC Front in Drake Passage (covering about 3% of the circumpolar longitudes
between 48°W and 64°W) is on the order of 10% of the heat lost to the atmosphere south of
60°S. |
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