The sverdrup, named in honour of the pioneering oceanographer Harald Sverdrup, is a unit of measure of volume transport. It is used almost exclusively in oceanography, to measure the transport of ocean currents. Its symbol is Sv. Note that the sverdrup is not an SI unit, and that its symbol conflicts with the sievert's symbol. It is equivalent to 106 cubic metres per second (0.001 km3/s, or about 264 million U.S. gallons per second). The entire global input of fresh water from rivers to the ocean is equal to about 1 sverdrup.
The water transport in the Gulf Stream gradually increases from 30 Sv in the Florida Current to a maximum of 150 Sv at 55°W longitude. The heat carried within this volume equals roughly that transported through the atmosphere to make the relatively milder climate of north-western Europe.