Tasman Leakage of intermediate waters as inferred from Argo floats

• Published in: Geophysical Research Letters
• Main Authors: Rosell Fieschi, Miquel, Rintoul, Stephen R., Gourrion, Jérôme, Pelegrí, Josep Lluís
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2013
• Subjects: Interbasin exchange; Antarctic Intermediate Water; Tasman Leakage; Southern Hemisphere supergyre; East Australian Current; Argo program; Antarctic; Indian; Pacific; The Antarctic; Antarc*; Antarctic Climate and Ecosystems Cooperative Research Centre
• Online Access: http://hdl.handle.net/10261/90093; https://doi.org/10.1002/2013GL057797

5 pages, 4 figures We use Argo float trajectories to infer ocean current velocity at the sea surface and 1000 dbar near Australia. The East Australian Current flows southward along the east coast of Australia at both surface and intermediate levels, but only the intermediate waters leak round the southern tip of Tasmania and cross the Great Australian Bight. We calculate the transport of Antarctic Intermediate Water (AAIW) between the southern Australian coast and the Antarctic Circumpolar Current (ACC) as the velocity at 1000 dbar times the layer thickness. Between March 2006 and December 2012, the Eulerian AAIW transport through 147°E ranges between 0 and 12.0 sverdrup (Sv). The mean Tasman Leakage of intermediate waters from the Pacific Ocean into the Indian Ocean, obtained using all Argo data until March 2013, is 3.8 ± 1.3 Sv. The mean intermediate water transport into the Indian Ocean through 115°E increases to 5.2 ± 1.8 Sv due to contributions from the westward recirculation of ACC waters. Keypoints An estimate of the Tasman Leakage, with error bars, is obtained A description of mean and seasonal velocity fields near Australia is provided Argo float data are used to calculate velocity vectors and water transports ©2013. American Geophysical Union. All Rights Reserved Funding for this work comes from the Spanish Ministerio de Ciencia e Innovación through project “Tipping Corners in the Meridional Overturning Circulation” (TIC-MOC, reference CTM2011-28867). Miquel Rosell-Fieschi would also like to acknowledge the Ministerio de Ciencia e Innovación for funding through a FPU grant. This work was supported in part by the Australian Government’s Cooperative Research Centres Program, through the Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC), and by the Department of Climate Change and Energy Efficiency, through the Australian Climate Change Science Program Peer Reviewed