A joint oceanographic research endeavor of Indonesia and the United States whose primary goal is to study the circulation and water mass stratification within the Indonesian Seas, especially to determine sources, pathways, and mixing histories of the throughflow water masses for the monsoon extremes. Arlindo is an acronym for Arus Lintas Indonesia, meaning ``throughflow in the Bahasa Indonesian language.

The first stage of the project, Arlindo Mixing, consisted of a suite of CTD measurements extending to the seafloor or 3000 dbar, tracer chemistry, and biological productivity stations obtained from the Indonesian research vessel Baruna Jaya I during the southeast monsoon of 1993 (Aug. 6 to Sept. 12) and northwest monsoon of 1994 (Jan. 25 to Mar. 3). The results have been summarized as:

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 mostxi 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.

The second stage was called Arlindo Circulation, whose goal was to resolve the throughflow transport and velocity field across the central passages of the Indonesian Seas. It took place from Nov. 20-Dec. 15, 1996 and Feb. 17-Mar. 7, 1988. The third stage is called Arlindo Monitoring and is intended to provide a long term data set of the throughflow to enable study at timescales of ENSO events. It is scheduled from 1998 to 2007.