Editing Sverdrup

{{Other uses}}
{{Short description|Unit of measurement}}
{{Infobox unit
| name         = Sverdrup
| image        = Labrador Current.jpg
| caption      = 
| standard     = 
| quantity     = [[Volumetric flow rate]]
| symbol       = Sv
| symbol2      = 
| namedafter   = 
| extralabel   = 
| extradata    = 
| units1       = {{val||u=m3|up=s}}
| inunits1     = 1 million
| units2 = US gallons/s
| inunits2 = 264 million 
| units3 = {{val||u=cuft|up=s}}
| inunits3 = 35 million
}}
In [[oceanography]], the '''sverdrup''' (symbol: '''Sv''') is a non-[[International System of Units|SI]] [[Metric_units#Volume_flow_rate|metric unit]] of [[volumetric flow rate]], with {{val|1|u=Sv}} equal to {{convert|1|e6m3/s|cuft/s|0}}.<ref>{{cite web |url=https://oceancurrents.rsmas.miami.edu/glossary.html#S |title=Glossary |website=Ocean Surface Currents |publisher=[[University of Miami]] [[Rosenstiel School of Marine, Atmospheric, and Earth Science]] |access-date=2019-04-15}}</ref><ref>{{Cite web |url=http://www.ecoworld.com/technology/sverdrups-brine.html |title=Sverdrups & Brine |website=Ecoworld |archive-url=https://web.archive.org/web/20110120155822/http://www.ecoworld.com/technology/sverdrups-brine.html |archive-date=20 January 2011 |url-status=dead |access-date=12 August 2017 }}</ref> It is equivalent to the SI derived unit cubic [[hectometer]] per second (symbol: hm<sup>3</sup>/s or hm<sup>3</sup>⋅s<sup>−1</sup>): {{val|1|u=Sv}} is equal to {{val|1|u=hm<sup>3</sup>/s}}. It is used almost exclusively in [[oceanography]] to measure the volumetric rate of transport of [[ocean current]]s. It is named after [[Harald Sverdrup (oceanographer)|Harald Sverdrup]].  

One sverdrup is about five times what is carried at the estuary by the world's largest river, the Amazon. In the context of [[ocean current]]s, a volume of one million cubic meters may be imagined as a "slice" of ocean with dimensions {{val|1|ul=km}} × {{val|1|u=km}} × {{val|1|u=m}} (width × length × thickness) or a cube with dimensions {{val|100|u=m}} × {{val|100|u=m}} × {{val|100|u=m}}. 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 [[velocity|meters per second]]). Thus, a hypothetical current {{val|50|u=km}} wide, {{val|500|u=m}} ({{val|0.5|u=k}}m) deep, and moving at {{val|2|u=m/s}} would be transporting {{val|50|u=Sv}} of water.

The sverdrup is distinct from the SI [[sievert]] unit or the non-SI [[svedberg]] unit. All three use the same symbol, but they are not related.

== History ==
The sverdrup is named in honor of the Norwegian oceanographer, meteorologist and polar explorer [[Harald Sverdrup (oceanographer)|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.<ref name=":0">{{cite journal |last1=Eldevik |first1=Tor |last2=Haugan |first2=Peter Mosby |date=2020-04-06 |title=That's a lot of water |journal=Nature Physics |language=en |volume=16 |issue=4 |pages=496 |doi=10.1038/s41567-020-0866-0 |s2cid=216292609 |issn=1745-2481|doi-access=free }}</ref>

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.<ref name=":0" />

== Examples ==
The water transport in the [[Gulf Stream]] gradually increases from {{val|30|u=Sv}} in the [[Florida Current]] to a maximum of {{val|150|u=Sv}} south of Newfoundland at the [[longitude]] 55°&nbsp;W.<ref>{{cite web |url=http://oceancurrents.rsmas.miami.edu/atlantic/gulf-stream.html |title=The Gulf Stream |website=Ocean Surface Currents |publisher=[[University of Miami]] [[Rosenstiel School of Marine, Atmospheric, and Earth Science]] |access-date=12 August 2017 }}</ref>

The [[Antarctic Circumpolar Current]], at approximately {{val|125|u=Sv}}, is the largest ocean current.<ref>{{cite web |url=http://oceancurrents.rsmas.miami.edu/southern/antarctic-cp.html |title=The Antarctic Circumpolar Current |website=Ocean Surface Currents |publisher=[[University of Miami]] [[Rosenstiel School of Marine, Atmospheric, and Earth Science]] |access-date=12 August 2017 }}</ref>

The entire global input of [[fresh water]] from rivers to the ocean is approximately {{val|1.2|u=Sv}}.<ref>{{cite journal |last1=Lagerloef |first1=Gary |last2=Schmitt |first2=Raymond |last3=Schanze |first3=Julian |last4=Kao |first4=Hsun-Ying |date=2010-12-01 |title=The Ocean and the Global Water Cycle |url=https://tos.org/oceanography/article/the-ocean-and-the-global-water-cycle |journal=Oceanography |volume=23 |issue=4 |pages=82–93 |doi=10.5670/oceanog.2010.07|doi-access=free }}</ref>

== References ==
{{reflist}}

[[Category:Non-SI metric units]]
[[Category:Oceanography]]
[[Category:Units of flow]]