strait heads in a generally north eastern direction, while gradually narrowing. At its narrowest point between the Alor Archipelago and Timor, it is wide, and its navigable waters are across. Beyond the end of the channel at the strait's north eastern extremity, between the islands of Alor and Atauro, is the Flores Sea to the north west and north, and the Banda Sea to the north east. That channel is wide at its narrowest point, where the navigable waters are across. To the east of the strait, and linking with it south of Atauro, is Wetar Strait. To the east of the latter strait are the south eastern reaches of the Banda Sea, and the southernmost of the Maluku Islands. As such, Ombai Strait is one of two deep water passages in the Indonesian archipelago that link the waters of the Pacific and Indian Oceans, the other one being Wetar Strait. The archipelago is the only interocean connection on earth at low latitudes, and the exchange of water between the two oceans is known as the Indonesian Throughflow (ITF). The ITF flows in a generally north east to south west direction. Its main pathway runs from the Pacific Ocean into the Banda Sea via the Celebes Sea, Makassar Strait and the Java and Flores Seas. Some of the ITF then passes directly into Ombai Strait, and some of it flows there indirectly, around Wetar Island's eastern end, and then via Wetar Strait. By this and other ITF pathways, nutrient-rich water from the Pacific Ocean runs into the Indian Ocean, at a rate 50 times faster than the discharge of the Amazon River. During El Niño, the water is cooler and inhibits rain. In Ombai Strait, there is also a counterflowing eastwards current, which affects the strait's overall mix of nutrients, temperatures and salinity levels. The eastwards current is an extension of the South Java Current (SJC), and its deeper Undercurrent (SJUC), from the Savu Sea into the strait. During the dry season (March–November), the strong, prevailing westwards ITF currents in the strait are at an annual maximum at the surface in the southern part of the strait, and a front appears to trap the portion of the SJC inside the strait to within ∼ of the strait's northern boundary. By contrast, the SJUC, when present, is observed across the entire strait. The ITF currents are at their weakest during the