Decadal variability of the Pacific subtropical cells and their influence on the southeast Indian Ocean

Historical sea level records reveal that a strengthening of the Pacific subtropical cells (STCs) since the early‐1990's has reversed a multi‐decadal weakening tendency. Stronger STCs correspond to a stronger Leeuwin Current in the southeast Indian Ocean (SEIO) and a stronger Indonesian Throughflow, due to dynamic connections of the Pacific and SEIO through equatorial and coastal waveguides. Multi‐decadal trends of the STCs and their influence on the SEIO have confounded the detection of human induced global change signals in the short instrumental records of the two circulation systems.