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| Titel |
Upper ocean geostrophic transports in the North Atlantic based on EN3 data |
| VerfasserIn |
Bente Tiedje, Sebastian Brune, Johanna Baehr |
| 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 |
250092191
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| Publikation (Nr.) |
 EGU/EGU2014-6519.pdf |
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| Zusammenfassung |
| We present time series of the integrated zonal density differences and the upper ocean
geostrophic transports in the North Atlantic between 40°N and 60°N based on
the EN3 dataset from 1996 to 2012. We calculate zonal density differences from
the EN3 temperature and salinity fields remapped to a 1°x1° grid by averaging
all density values within a 10° band off either boundary. Due to the sparseness of
density values in space and/or time we average vertically from the top to ~100m and
temporally below ~1300m. Vertically integrated zonal density differences (~150m -
1150m) show a decrease of on average 0.0058 kg m-3/yr between 40°N and 50°N,
while between 50°N and 60°N the temporal changes are generally weaker and
not spatially uniform. In contrast, the vertically integrated basin wide zonal mean
density from EN3 shows a decrease for the entire range of latitudes (-0.0051 kg
m-3/yr).
We calculate upper ocean geostrophic transports from the full vertical profiles of the zonal
density gradients, assuming a reference level at the bottom and a zonally constant
mass balance correction. The resulting meridional transport integrated from the
surface to 1150m shows similar annual mean variability at 41°N as the transport
presented by Willis (2010). Consistent with the decreasing zonal density differences,
we find in the meridional transports a decrease of on average -0.25 Sv/yr between
40°N and 50°N, while between 50°N and 60°N the temporal changes are generally
weaker and not spatially uniform. These latitude-dependent temporal changes of the
meridional transports dominantly originate from the densities at the western boundary. |
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