Throughflow into the Indian Ocean through the Lombok Strait, January 1985–January 1986

Abstract

Recent papers (for example, refs 1 and 2) have raised the possibility, perhaps of global significance, that the rate of interbasin mass exchange between the Pacific and Indian Oceans through the Indonesian archipelago (referred to as the throughflow) is far higher than the value of 1–2 Sv (1 Sv = 10⁶ m³ s⁻¹) originally suggested in ref. 3. The elevated temperature and depressed salinity of throughflow water have a critical role in the heat and freshwater balance of the Indian Ocean⁴. Inasmuch as the Indonesian through-flow route is the only interocean basin connection in tropical latitudes, its presence and strength have important implications to heat flux through the global ocean⁵. Present estimates of the magnitude of the throughflow are all by various indirect methods and vary greatly, from 1.5 to 20 Sv (refs 1–3, 6–8 reviewed in ref. 5). We present here direct (current meter) observations that support the existence of a large throughflow.