A weaker Agulhas Current leads to more Agulhas leakage

van Sebille, E., Biastoch, A., Van Leeuwen, P. J. and de Ruijter, W. P. M. (2009) A weaker Agulhas Current leads to more Agulhas leakage. Geophysical Research Letters, 36 (3). L03601. ISSN 0094-8276 doi: 10.1029/2008GL036614

Abstract/Summary

Time series of transports in the Agulhas region have been constructed by simulating Lagrangian drifter trajectories in a 1/10 degree two-way nested ocean model. Using these 34 year long time series it is shown that smaller (larger) Agulhas Current transport leads to larger (smaller) Indian-Atlantic inter-ocean exchange. When transport is low, the Agulhas Current detaches farther downstream from the African continental slope. Moreover, the lower inertia suppresses generation of anti-cyclonic vorticity. These two effects cause the Agulhas retroflection to move westward and enhance Agulhas leakage. In the model a 1 Sv decrease in Agulhas Current transport at 32°S results in a 0.7 ± 0.2 Sv increase in Agulhas leakage.