HR: 1300h
AN: OS52D-13    [PDF]
TI: The Effects of the Indonesian Throughflow on the Indian Ocean Meridional Overturning Circulation and Heat Budget
AU: * Song, Q
EM: qsong@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61, Route 9W, Palisades, NY 10027
AB: The sensitivity of the meridional overturning circulation (MOC) and heat budget of the Indian Ocean to the Indonesian Throughflow (ITF) transport variability is investigated in an ocean general circulation model that is coupled to an atmospheric mixed layer model. Four experiments are performed: (1) ITF blocked, (2) 10Sv ITF, (3) 20Sv ITF and (4) 10Sv ITF but with vertical transport profile more thermocline intensified. The Indian Ocean MOC responses to the net transport input of ITF by introducing net southward transport south of the entrance latitude of ITF to the Indian Ocean (about 10S). The compensating southward transport in the southern Indian Ocean occurs mostly in the upper 1000m within the Agulhas Current with minor proportion within the Leeuwin Current. The deep overturning cell (below 1500m) south of 10S is insensitive to the ITF transport variability. The ITF heat flux into the Indian Ocean associated with its transport is mostly compensated by the ocean meridional heat flux (OMHF) in the southern Indian Ocean, while surface heat fluxes over the Indian basin plays a minor role and insignificantly varies with the ITF transport. Comparing any ITF-open scenario with the ITF-blocked scenario, the velocity anomalies dominate over the temperature anomalies in generating the compensating OMHF. The OMHF is decomposed into two components, the meridional overturning component and the horizontal gyre component. We find that the former is more important in delivering the ITF heat flux southward out of the Indian basin than the latter. With more ITF transport in the thermocline rather than in the surface layer and hence less ITF heat flux into the Indian Ocean, the both the southward OMHF and the ocean heat loss is lower, but the magnitudes depend on the ITF profile difference.
DE: 4215 Climate and interannual variability (3309)
DE: 4231 Equatorial oceanography
DE: 4255 Numerical modeling
DE: 4512 Currents
DE: 4572 Upper ocean processes
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting