The intraseasonal to interannual variability of the Indonesian throughflow and its regional implications

The flow of water from the equatorial Pacific Ocean to the Indian Ocean through the Indonesian seas has local, regional and global importance. The Indonesian Throughflow (ITF) is involved in modification of Pacific Ocean water masses, poleward transport of ocean heat, interactions with the Asian/Australian monsoons, interactions with El Niño/Southern Oscillation (ENSO) and perhaps in the selective communication between the Indian and Pacific Oceans. This dissertation examines the thermal characteristics of the ITF on intraseasonal to interannual time scales and the impact of external dynamics from the Indian and Pacific Oceans on ITF variability. ITF heat transport is calculated from mooring measurements made continuously between November 1996–July 1998 in the Makassar Strait, the path through which 90% of the ITF passes. The impact of this heat transport on the Indian Ocean basin is discussed. Historical temperature data collected since 1985 is used to examine the interannual variability of the Indonesian seas thermocline and to construct a long-term volume transport proxy record. Sea surface height data from satellite altimetry is employed to examine the impact of dynamic features originating in the Pacific and Indian Oceans on the ITF. The fortuitous coincidence of instrumentation around the interior and exterior Indonesian seas during Spring 1997 allowed for the description of a strong Indian Ocean Kelvin wave on Makassar throughflow. This event is described and altimetry data from 1992–2001 is examined to determine if the Spring 1997 event is representative of a annual or semi-annual occurrence.