In company with George Bass, he set out to confirm that a body of water separates Tasmania from the mainland. I was obliged . . . This we considered to be strong proof, not only of the real existence of a passage betwixt this land and New South Wales, but also that the entrance into the Southern Indian Ocean could not be far distant. Bass and Flinders completed their three months' circumnavigation in early 1799. Drifting instruments which are tracked by satellites, and satellites themselves, also contribute information to generate a picture of the Southern Ocean and Tasman Sea and life within these vast and complex waters.
Satellites provide an extensive cover of an ocean's surface.
They map the sea surface temperature patterns each time they pass over and from these, surface currents can be roughly inferred. But satellites do not give a detailed picture of currents from the surface to the sea floor. This can only be obtained through comprehensive sampling at sea using instruments that take measurements every few centimetres as they are lowered from Franklin to the sea floor. Drifter and satellite images have revealed that the Zeehan Current,which is above the continental slope west of King Island, moves onto the continental shelf for its run down to southern Tasmania. It then turns to the southeast.