Decadal weakening of the shallow overturning circulation in the South Indian Ocean

Analysis of satellite measurements of wind stress and sea level suggests (1) a near-decadal slowdown of the shallow overturning cell in the South Indian Ocean (SIO) associated with a significant weakening of the southeasterly trade during 1992-2000, and (2) a relatively steady cross-equatorial shallow overturning cell. The slowdown of the SIO cell, estimated to be 6.8 Sv over the 9 year period, is about 70% its averaged strength (about 10 Sv). The results have important implications to upper-ocean heat content, decadal climate variability, and biochemistry in the region.