05.12 - 09.12.2005
San Francisco, USA

PAGES-IMAGES co-sponsor a special session at the upcoming AGU Fall Meeting and invite contributions:

OS07: *Indonesian Throughflow Variability: Present and Past - a PAGES-IMAGES session*

Arnold L. Gordon, LDEO, Columbia University
Thorsten Kiefer, PAGES Office, Bern
Wolfgang Kuhnt, Ralph Schneider, University of Kiel

Session Description:
The Indonesian throughflow (ITF) injects Pacific Ocean tropical water into the Indian Ocean. It is constrained by the complex pathways through the Indonesian Archipelago, with passages of varied widths and topographic barriers. The transport and thermohaline stratification of the ITF influences the heat and freshwater budgets of the Pacific and Indian Oceans and alters patterns of heat and water vapor exchange with the atmosphere. The ITF may therefore be considered a key component for regional climate systems such as the El Nino Southern Oscillation and the Australasian monsoon. The ITF may play a central role in the global "conveyor" circulation, and therefore also exert critical control on global climate. The ITF has been observed to vary on seasonal and interannual time scales in response to changing patterns of regional climate. On longer, geological timescales, there is evidence that the ITF was substantially modulated by changes in the geometry of the Indonesian pathways due to sea level changes during the Pleistocene and tectonic reorganizations of the archipelago during the Cenozoic. However, our quantitative knowledge on the magnitude, dynamics, and mechanisms of ITF variability as well as its effect on regional oceanography and climate requires improvement for the ITF to be realistically included in climate (prediction) scenarios.

Global ocean observations and satellite observations provide a growing database for advancement in that field. Likewise, paleoceanographic coring campaigns generate new high-resolution data on past ITF variability. Results from numerical modeling of the throughflow on a large scale (including Pacific and Indian oceans) and in high resolution in the Indonesian region are crucial for the analysis of observed data. This session seeks to bring together observation based scientists and modelers from both, the oceanographic and the paleoceanographic communities. Synergies are expected towards a better quantitative understanding of the operation of the Pacific-Indian interocean exchange and its effect on regional and global climate. Studies from between the Western Pacific to the Agulhas region (and possibly beyond) on timescales from human to extra-orbital are welcome.