On the sources of Agulhas Current

Lively Data: February 17, 2009

Maps of merged Absolute Dynamic Topography in cm (top) and absolute geostrophic currents in cm/s (below) the June 11, 2008, to the south of Madagascar. For the MADT, choose DT - Global- Maps of Absolute Dynamic Topography Merged, the date, the geographical area, and color fill levels (100)(180,260,1)(280). A red rectangle limits the borders for the map of geostrophic current for which it is preferable to have a smaller area. For the map of geostrophic current (below), choose DT - Global- Maps of Absolute Geostrophic Velocities, Variable(s): Vector (U,V), the date, and the geographical area.

The delayed-time dataset has been updated in the LAS: further 6 months extend the dataset that it now comprised between 1992/10/14 and 2008/06/11.

The Agulhas system is characterized by an intense mesoscale activity and was several times shown in our Lively data. We focus here on the source region of the Agulhas current which is well visible with maps of ADT and geostrophic currents, near the southern coasts of Madagascar.

The southern branch of the East Madagascar Current (SEMC) comes from the eastern side of the island and flowing toward SW. On the southwest of Madagascar, it is separated into two branches: the northern one will be linked westward to the Agulhas Current and the southerner branch will be retroflected eastward and will be connected to the Subtropical Indian Ocean Countercurrent (SICC). Choosing a favorable date (here the latest avaiblable date for the delayed-time data), the map of MADT and geostrophic current  provide evidence of this area showing a major hill and valley which correspond to an anticyclonic (anticlockwise) and cyclonic (clockwise) motion respectively.

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