The Fate of the East Madagascar Current
Schematic — AVHRR (June 1984) (from Lutjeharms, Deep Sea Res., 1988) SeaWiFS 6-day Chl composite
Retroflection ?? Series of 6-day composites 12 days apart “Retro-fiction” Quartly, G.D., J.J.H. Buck, M.A. Srokosz and A.C. Coward, 2006, Eddies around Madagascar — the retroflection re-considered, J. Mar. Sys. 63 (3-4) OCCAM Sea Surf. Ht Zero of Wind Stress Curl lies further south No eastward current for it to feed
SIOCC Siedler, G., et al.(2006), Structure and origin of the subtropical South Indian Ocean Countercurrent, Geophys. Res. Lett., 33, L24609 Siedler, G. et al. (2009), Modes of the southern extension of the East Madagascar Current, J. Geophys. Res., 114, C01005
Mean Dynamic Topography Rio, M.H. et al.(2011), New CNES ‐ CLS09 global mean dynamic topography computed from the combination of GRACE data, altimetry, and in situ measurements, J. Geophys. Res., 116, C07018 Schematic of counter-rotating eddies
Surface drifters
Model representation of "SIOCC"
ADCP section
Ship-mounted ADCP moorings
+ Sat imagery CC SST
Comparison with altimetry Velocity (m/s) Jason-1 altimeter
Modes of variation
Summary South Indian Ocean Counter Current In SIO there is a mean eastward flow at ~25˚S Connection to EMC: Some waters from EMC turn back to go east … but does the mean current really exist? … but is that really a “retroflection”?