Arlindo Mixing


Project Description

CTD Stations for the 1993 Southeast Monsoon Cruise

CTD Stations for the 1994 Northwest Monsoon Cruise

Summary of Arlindo Mixing Results

Results from Arlindo Mixing can be summarized in a schematic diagram of the various flow through paths evident from water mass analysis. What follows is a brief description of the reasoning followed in the construction of the flow schematic.

The primary interocean throughflow path in the upper thermocline is that of North Pacific thermocline water flowing through the Makassar Strait into the Flores and southern Banda Seas before curling southward into the Timor Sea and Indian Ocean. This path tracks the most persistent course of water masses core layer indicators along a potential throughflow pathway. Even in the southern Banda Sea the North Pacific core layer indicators are evident, albeit very attenuated; they are not observed in the northern Banda Sea, which attests to the Makassar/Flores origin. The sill at the southern end of Makassar Strait is about 550 m deep. No signs of deep water upwelling lifting over the sill is evident. An attenuated, fragmented thermocline salinity and CFC maximum layer in Makassar Strait during the NWM relative to the SEM, suggests that the throughflow slackens in that season, allowing accumulative effects of local mixing.

East of Sulawesi there is little evidence of North Pacific water mass throughflow into the Banda Sea. The North Pacific thermocline water entering the northwest corner of the Maluku Sea, exits back to the north in the northeast corner of the Maluku Sea. The presence of relatively salty water of South Pacific origin is observed in the 10°-14°C interval in the Seram Sea. This water enters the Seram Sea directly from the South Pacific via the New Guinea Coastal Current and Halmahera Sea (sill depth near 500 m). Below the thermocline the main source of the throughflow is South Pacific water masses, though they are derived from a more indirect route, via the North Pacific's Mindanao Current, entering the Indonesian Seas at the Maluku Sea. It is this water that spills over the 1940 m deep Lifamatola Sill into the depths of the Banda Sea.

Designed by: D. Jarvis Belinne
Lamont-Doherty Earth Observatory of Columbia University