Ocean surface

Discovering an ocean current using altimetry data

04 April 2007 00:00 UTC

Ocean surface
Ocean surface

Ocean currents can be discovered in the 21st century: oceanographers found a current, the South Indian Counter Current, looking closely at altimetry data.

Last Updated

14 May 2021

Published on

04 April 2007


This surface current, which goes eastwards at about 25°S, from Madagascar to about 100°E, is the counterpart of a westward current closer to Equator. If it can't be seen at every time, averaging current velocities in the region shows it clearly.

Altimetry measurements represent a huge quantity of information on the ocean (a Topex/Poseidon 10-day cycle gathered more measurements than the previous 100 years of in situ measurements). Continuity of these measurement over long period will bring to light new phenomena, not very prominent on instantaneous views, but that show up over longer periods.


Ocean Currents in the South Indian Ocean

Geostrophic surface currents (deduced from absolute dynamic topography)
averaged over 5 years (August 2001–May 2006). Pink lines are in situ observations (Woce program data). Source: University of Cape Town.

Geostrophic surface currents

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