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An Observed 20 Yr Time-series of Agulhas Leakage : Volume 11, Issue 1 (15/01/2014)

By Le Bars, D.

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Book Id: WPLBN0004020790
Format Type: PDF Article :
File Size: Pages 26
Reproduction Date: 2015

Title: An Observed 20 Yr Time-series of Agulhas Leakage : Volume 11, Issue 1 (15/01/2014)  
Author: Le Bars, D.
Volume: Vol. 11, Issue 1
Language: English
Subject: Science, Ocean, Science
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Historic
Publication Date:
2014
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

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Biastoch, A., Dijkstra, H. A., M. De Ruijte, W. P., Durgadoo, J. V., & Bars, D. L. (2014). An Observed 20 Yr Time-series of Agulhas Leakage : Volume 11, Issue 1 (15/01/2014). Retrieved from http://worldlibrary.net/


Description
Description: IMAU, Utrecht University, P.O. Box 80.005, 3508 TA Utrecht, the Netherlands. We provide a time series of Agulhas leakage anomalies over the last twenty years from satellite altimetry. Until now, measuring the interannual variability of Indo-Atlantic exchange has been the major barrier in the investigation of the dynamics and large scale impact of Agulhas leakage. We compute the difference of transport between Agulhas Current and Agulhas Return Current which allows to deduce Agulhas leakage. The main difficulty is to separate the Agulhas Return Current from the southern limb of the subtropical supergyre south of Africa. For this purpose, an algorithm that uses absolute dynamic topography data is developed. The algorithm is applied to a state-of-the-art ocean model. The comparison with a Lagrangian method to measure the leakage allows to validate the new method. An important result is that it is possible to measure Agulhas leakage in this model using the velocity field along a section that crosses both the Agulhas Current and the Agulhas Return Current. In the model a good correlation is found between measuring leakage using the full depth velocities and using only the surface geostrophic velocities. This allows us to extend the method to along-track absolute dynamic topography from satellites. It is shown that the accuracy of the mean dynamic topography does not allow to determine the mean leakage but that leakage anomalies can be accurately computed.

Summary
An observed 20 yr time-series of Agulhas leakage

Excerpt
Ansorge, I. J., Speich, S., Froneman, P. W., Rouault, M., and Garzoli, S.: Monitoring the oceanic flow between Africa and Antarctica: report of the first GoodHope cruise, S. Afr. J. Sci., 101, 29–35, 2005.; Backeberg, B. C., Penven, P., and Rouault, M.: Impact of intensified Indian Ocean winds on mesoscale variability in the Agulhas system, Nature Climate Change, 2, 1–5, 2012.; Bang, N. D. and Andrews, W. R. H.: Direct current measurements of a shelf-edge frontal jet in the southern Benguela system, J. Mar. Res., 32, 405–417, 1974.; Beal, L. M., De Ruijter, W. P. M., Biastoch, A., and Zahn, R.: On the role of the Agulhas system in ocean circulation and climate, Nature, 472, 429–436, 2011.; Biastoch, A. and Böning, C. W.: Anthropogenic impact on Agulhas leakage, Geophys. Res. Lett., 40, 1138–1143, 2013.; Biastoch, A., Lutjeharms, J. R. E., Böning, C. W., and Scheinert, M.: Mesoscale perturbations control inter-ocean exchange south of Africa, Geophys. Res. Lett., 35, 2000–2005, 2008.; Biastoch, A., Böning, C. W., Schwarzkopf, F. U., and Lutjeharms, J. R. E.: Increase in Agulhas leakage due to poleward shift of Southern Hemisphere westerlies, Nature, 462, 495–498, 2009.; Boebel, O., Lutjeharms, J. R. E., Schmid, C., Zenk, W., Rossby, T., and Barron, C. N.: The Cape Cauldron: a regime of turbulent inter-ocean exchange, Deep-Sea Res.-Pt. II, 50, 57–86, 2003.; De Ruijter, W. D.: Asymptotic analysis of the Agulhas and Brazil current systems, J. Phys. Oceanogr., 12, 361–373, 1982.; Lutjeharms, J., Boebel, O., and Rossby, H. T.: Agulhas cyclones, Deep-Sea Res.-Pt. II, 50, 13–34, 2003.; Lutjeharms, J., Durgadoo, J., and Ansorge, I.: Surface drift at the western edge of the Agulhas Bank, South African Journal of Science, 103, 63–68, 2007.; De Ruijter, W. P. M., Biastoch, A., Drijfhout, S. S., Lutjeharms, J. R. E., Matano, R. P., Pichevin, T., Van Leeuwen, P. J., and Weijer, W.: Indian-Atlantic interocean exchange: dynamics, estimation and impact, J. Geophys. Res., 104, 20885–20910, 1999.; Dencausse, G., Arhan, M., and Speich, S.: Spatio-temporal characteristics of the Agulhas Current retroflection, Deep-Sea Res.-Pt. I, 57, 1392–1405, 2010.; Dijkstra, H. A. and de Ruijter, W. P. M.: On the physics of the Agulhas Current: steady retroflection regimes, J. Phys. Oceanogr., 31, 2971–2985, 2001.; Doglioli, A. M., Veneziani, M., Blanke, B., Speich, S., and Griffa, A.: A Lagrangian analysis of the Indian-Atlantic interocean exchange in a regional model, Geophys. Res. Lett., 33, L14611, doi:10.1029/2006GL026498, 2006.; Durgadoo, J. V., Loveday, B. R., Reason, C. J. C., Penven, P., and Biastoch, A.: Agulhas leakage predominantly responds to the Southern Hemisphere westerlies, J. Phys. Oceanogr., 43, 2113–2131, 2013.; Franzese, A. M., Hemming, S. R., and Goldstein, S. L.: Use of strontium isotopes in detrital sediments to constrain the glacial position of the Agulhas Retroflection, Paleoceanography, 24, 1–12, 2009.; Gill, A. E.: Atmosphere–Ocean Dynamics, Vol. 30, Academic Press, San Diego, California, USA, 1982.; Gordon, A. L.: Interocean exchange of thermocline water, J. Geophys. Res., 91, 5037–5046, 1986.; Large, W. G. and Yeager, S. G.: The global climatology of an interannually varying air-sea flux data set, Clim. Dynam., 33, 341–364, 2009.; Lutjeharms, J. and Cooper, J.: Interbasin leakage through Agulhas current filaments, Deep-Sea Res.-Pt. I, 43, 213–238, 1996.; Le Bars, D., De Ruijter, W. P. M., and Dijkstra, H. A.: A new regime of the Agulhas Current retroflection: turbulent choking of Indian-Atlantic leakage, J. Phys. Oceanogr., 42, 1158–1172, 2012.; Le Bars, D., Dijkstra, H. A., and De Ruijter, W. P. M.: Impact of the Indonesian Throughflow on Agulhas leakage, Ocean Sci., 9, 773–785, doi:10.5194/os-9-773-2013, 2013.; Madec, G.: NEMO ocean engine, Note du Pole de modeisation de líInstitut Pierre-Simon Laplace No

 

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