Journal cover Journal topic
Ocean Science An interactive open-access journal of the European Geosciences Union
Ocean Sci., 5, 511-521, 2009
https://doi.org/10.5194/os-5-511-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.
 
03 Nov 2009
Relating Agulhas leakage to the Agulhas Current retroflection location
E. van Sebille1, C. N. Barron2, A. Biastoch3, P. J. van Leeuwen1,*, F. C. Vossepoel1,4,**, and W. P. M. de Ruijter1 1Institute for Marine and Atmospheric Research Utrecht, Utrecht University, The Netherlands
2Naval Research Laboratory, Stennis Space Center, Mississippi, USA
3Leibniz Institute of Marine Sciences, Kiel, Germany
4SRON Netherlands Institute for Space Research, Utrecht, The Netherlands
*now at: Department of Meteorology, University of Reading, UK
**now at: Shell International Exploration and Production B.V., Rijswijk, The Netherlands
Abstract. The relation between the Agulhas Current retroflection location and the magnitude of Agulhas leakage, the transport of water from the Indian to the Atlantic Ocean, is investigated in a high-resolution numerical ocean model. Sudden eastward retreats of the Agulhas Current retroflection loop are linearly related to the shedding of Agulhas rings, where larger retreats generate larger rings. Using numerical Lagrangian floats a 37 year time series of the magnitude of Agulhas leakage in the model is constructed. The time series exhibits large amounts of variability, both on weekly and annual time scales. A linear relation is found between the magnitude of Agulhas leakage and the location of the Agulhas Current retroflection, both binned to three month averages. In the relation, a more westward location of the Agulhas Current retroflection corresponds to an increased transport from the Indian Ocean to the Atlantic Ocean. When this relation is used in a linear regression and applied to almost 20 years of altimetry data, it yields a best estimate of the mean magnitude of Agulhas leakage of 13.2 Sv. The early retroflection of 2000, when Agulhas leakage was probably halved, can be identified using the regression.

Citation: van Sebille, E., Barron, C. N., Biastoch, A., van Leeuwen, P. J., Vossepoel, F. C., and de Ruijter, W. P. M.: Relating Agulhas leakage to the Agulhas Current retroflection location, Ocean Sci., 5, 511-521, https://doi.org/10.5194/os-5-511-2009, 2009.
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