Variability of the Indo-Pacific Ocean exchanges

The ECCO–GODAE global estimate of the ocean circulation 1992–2007 is analyzed in the region of the Indonesian Throughflow (ITF), including the Southern Ocean flow south of Australia. General characteristics are an intense month-to-month noise, only weak trends, and an important annual cycle (which is not the focus of attention). Apart from the details of the unresolved flows within the various passages, and right on the equator, the region and its large-scale climate effects appears to be accurately diagnosed by large-scale geostrophic balance, so that the ITF can be calculated either from the upstream or the downstream balanced flow (but no simple reference level can be defined). The INSTANT program occurs during a more or less typical three-year period. Indications of response to the large 1997–1998 El Niño are weak.