In oceanography, the sverdrup (symbol: Sv) is a non- SI metric unit of

volumetric flow rate In physics and engineering, in particular fluid dynamics, the volumetric flow rate (also known as volume flow rate, or volume velocity) is the volume of fluid which passes per unit time; usually it is represented by the symbol (sometimes ). I ...

, with equal to . It is equivalent to the SI derived unit cubic hectometer per second (symbol: hm³/s or hm³⋅s⁻¹): 1 Sv is equal to 1 hm³/s. It is used almost exclusively in oceanography to measure the volumetric rate of transport of

ocean current An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contou ...

s. It is named after Harald Sverdrup. One sverdrup is about five times what is carried by the world’s largest river, the Amazon. In the context of

s, a volume of one million cubic meters may be imagined as a "slice" of ocean with dimensions × × (width × length × thickness). At this scale, these units can be more easily compared in terms of width of the current (several km), depth (hundreds of meters), and current speed (as meters per second). Thus, a hypothetical current wide, 500 m (0.5 km) deep, and moving at 2 m/s would be transporting of water. The sverdrup is distinct from the SI sievert unit or the non-SI svedberg unit. All three use the same symbol. They are not related.

History

The sverdrup is named in honor of the Norwegian oceanographer, meteorologist and polar explorer Harald Ulrik Sverdrup (1888–1957), who wrote the 1942 volume ''The Oceans, Their Physics, Chemistry, and General Biology'' together with Martin W. Johnson and Richard H. Fleming. In the 1950s and early 1960s both Soviet and North American scientists contemplated the damming of the Bering Strait, thus enabling temperate Atlantic water to heat up the cold Arctic Sea and, the theory went, making Siberia and northern Canada more habitable. As part of the North American team, Canadian oceanographer Maxwell Dunbar found it "very cumbersome" to repeatedly reference millions of cubic meters per second. He casually suggested that as a new unit of water flow, "the inflow through Bering Strait is one sverdrup". At the Arctic Basin Symposium in October 1962, the unit came into general usage.

Examples

The water transport in the

Gulf Stream The Gulf Stream, together with its northern extension the North Atlantic Drift, is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the Uni ...

gradually increases from in the Florida Current to a maximum of south of Newfoundland at 55° W

longitude Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek let ...

. The Antarctic Circumpolar Current, at approximately , is the largest ocean current. The entire global input of

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does incl ...

from rivers to the ocean is approximately .

References

{{Reflist Oceanography Units of flow Non-SI metric units