Sea surface height signals as indicators for oceanic meridional mass transports


Hirschi, Joël J.-M., Killworth, Peter D., Blundell, Jeffrey R. and Cromwell, David (2009) Sea surface height signals as indicators for oceanic meridional mass transports. Journal of Physical Oceanography, 39, (3), 581-601. (doi:10.1175/2008JPO3923.1).

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Description/Abstract

Numerical models are used to test whether the sea surface height (SSH) can be used as an indicator for the
variability of Atlantic meridional oceanic mass transports. The results suggest that if the transports over the
western boundary current region and those in the eastern part of the basin are considered separately, significant
correlations (0.3–0.9) are found between zonal SSH differences and the meridional transports in the top
1100 m. Much weaker correlations are found for the basinwide transport, which corresponds to the surface
branch of the meridional overturning circulation (MOC). For the eastern and western branches of the meridional
transport, combining the SSH signal with the baroclinic structure obtained from Rossby wave theory
enables calculation of a quantitative estimate of the transport variability in the top 1100 m. The results of the
method are less convincing for the variability of the MOC. The reason for this is that even small relative errors
in the variability of the eastern and western branches can be large compared with the MOC variability. These
errors project onto the sum of the eastern and western transports and therefore onto the surface branch of the
MOC. Nevertheless, being able to infer transport anomalies from SSH signals in the eastern and western parts
of the Atlantic might prove useful in interpreting MOC observations from the U.K. Natural Environment
Research Council Rapid Climate Change (RAPID) mooring array at 268N, which show a large subannual
variability that is mainly due to changes at the western boundary. Transports inferred from the SSH could help
to identify the origin of this variability and whether transport anomalies propagate into the western boundary
region from the basin interior or from other latitudes.

Item Type: Article
ISSNs: 0022-3670 (print)
Related URLs:
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Divisions: University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
University Structure - Pre August 2011 > National Oceanography Centre (NERC)
ePrint ID: 63288
Date Deposited: 26 Sep 2008
Last Modified: 27 Mar 2014 18:45
URI: http://eprints.soton.ac.uk/id/eprint/63288

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