IW01-29 POSTER

NEW CONCEPTS ON THE FLOW IN THE MOZAMBIQUE CHANNEL

H.RIDDERINKHOF (Netherlands Institute of Sea Research, PO Box 59, 1790 AB Den Burg, Netherlands, rid@nioz.nl); W. P. M. De. Ruijter (Institute for Marine and Atmospheric Research, Utrecht University, Princetonplein 5, 3584 CC Utrecht, Netherlands, ruijter@phys.uu.nl); J. R. E. Lutjeharms (Dept. Oceanography, University of Cape Town, 7700 Rondebosch, South Africa, johann@physci.uct.ac.za)

The Mozambique Current has been perceived as a western boundary current to the wind-driven system in the southwest Indian Ocean. It is supposed to be a key link in the, climatically important, global thermohaline circulation by carrying tropical surface and thermocline water poleward through the Mozambique Channel and eventually into the South Atlantic. Traditionally it has also been conceived as a main tributary to the Agulhas Current. Until rather recently, also most ocean models simulated the Mozambique Current as a weak, along-shelf, current with little variability. By contrast, modern satellite altimetric and other observations, as well as eddy permitting models indicate extraordinary high variability along its purported tajectory. To address these conundrums we have recently carried out the first research cruise designed specifically to investigate the nature and continuity of the Mozambique Current along its full length. It has revealed that no intense, cohe! rent, western boundary layer-type current exists in the Mozambique Channel. Instead, the flow is dominated by a train of large (diameters over 300 km) anti-cyclonic eddies that reach to the channel bottom. In the deep sea our observations have also identified a rather strong Mozambique Undercurrent which flows equatorward along the continental slope and carries intermediate and deep waters of Atlantic origin into the Channel.