The East Madagascar Current: Volume Transport and Variability Based on Long-Term Observations*

AbstractThis study provides a long-term description of the poleward East Madagascar Current (EMC) in terms of its observed velocities, estimated volume transport, and variability based on both ~2.5 yr of continuous in situ measurements and ~21 yr of satellite altimeter data. An array of five moorings was deployed at 23°S off eastern Madagascar as part of the Indian–Atlantic Exchange in present and past climate (INATEX) observational program. On average, the EMC has a horizontal scale of about 60–100 km and is found from the surface to about 1000-m depth. Its time-averaged core is positioned at the surface, at approximately 20 km from the coast, with velocity of 79 (±21) cm s−1. The EMC mean volume transport is estimated to be 18.3 (±8.4) Sverdrups (Sv; 1 Sv ≡ 106 m3 s−1). During the strongest events, maximum velocities and transport reach up to 170 cm s−1 and 50 Sv, respectively. A good agreement is found between the in situ transport estimated over the first 8 m of water column [0.32 (±0.13) Sv] with the...