Editing Labrador Sea (section)

==Oceanography==
[[File:LabradorCurrentus-coastguard.jpg|thumb|right|180px|Major North Atlantic currents]]
The Labrador Sea is about {{convert|3400|m|fathom ft|0|lk=out|abbr=in}} deep and {{convert|1000|km|mi nmi|0|abbr=in|lk=out}} wide where it joins the Atlantic Ocean. It becomes shallower, to less than {{convert|700|m|fathom ft|0|abbr=on}} towards Baffin Bay (see [[:File:IBCAO betamap.jpg|depth map]]) and passes into the {{convert|300|km|mi nmi|abbr=on}} wide [[Davis Strait]].<ref name=r1/> A {{convert|100|–|200|m|fathom ft|abbr=on}} deep [[turbidity current]] channel system, which is about {{convert|2|-|5|km|mi nmi |abbr=on}} wide and {{convert|3,800|km|mi nmi|abbr=on}} long, runs on the bottom of the sea, near its center from the [[Hudson Strait]] into the Atlantic.<ref>{{cite journal |title= Ice-sheet sourced juxtaposed turbidite systems in Labrador Sea |url= http://journals.hil.unb.ca/index.php/GC/article/view/3928 |journal= Geoscience Canada|volume=24|issue=1|page=3|author8=Heisee, R and Klaucke I|date= 3 March 1997 }}</ref><ref>{{cite journal|last1=Reinhard Hesse And Allan Rakofsky |title=Deep-Sea Channel/Submarine-Yazoo System of the Labrador Sea: A New Deep-Water Facies Model (1)|journal=AAPG Bulletin|volume=76|year=1992|doi=10.1306/BDFF88A8-1718-11D7-8645000102C1865D}}</ref> It is called the [[Northwest Atlantic Mid-Ocean Channel]] (NAMOC) and is one of the world's longest drainage systems of Pleistocene age.<ref name=r2>{{cite book|url=https://books.google.com/books?id=LuMgcgupaJcC&pg=PA286|page=286|title=Glaciated continental margins: an atlas of acoustic images|editor= Thomas A. Davies|author=Hesse, R., Klauck, I., Khodabakhsh, S. & Ryan, W. B. F. |year=1997|work=Glacimarine drainage systems in the deep-sea: the NAMOC system of the Labrador Sea and its sibling|publisher=Springer|isbn=0-412-79340-7}}</ref> It appears as a submarine river bed with numerous tributaries and is maintained by high-density turbidity currents flowing within the [[levee]]s.<ref>{{cite book|url=https://books.google.com/books?id=-N3nidyNoJUC&pg=PA234|page=234|title=Sedimentary basins: evolution, facies, and sediment budget|first=Gerhard|last=Einsele|publisher=Springer|year=2000|isbn=3-540-66193-X}}</ref>

The water temperature varies between {{Convert|-1|C}} in winter and {{Convert|5|-|6|C|F}} in summer. The salinity is relatively low, at 31–34.9 parts per thousand. Two-thirds of the sea is covered in ice in winter. Tides are [[Earth tide|semi-diurnal]] (i.e. occur twice a day), reaching {{Convert|4|m|fathom ft|abbr=on}}.<ref name=bse/>

There is an anticlockwise water circulation in the sea. It is initiated by the [[East Greenland Current]] and continued by the [[West Greenland Current]], which brings warmer, more saline waters northwards, along the Greenland coasts up to the Baffin Bay. Then, the [[Baffin Island Current]] and [[Labrador Current]] transport cold and less saline water southward along the Canadian coast. These currents carry numerous icebergs and therefore hinder navigation and exploration of the gas fields beneath the sea bed.<ref name=brit/><ref name=can>{{cite encyclopedia|url=https://www.thecanadianencyclopedia.ca/en/article/labrador-sea|title=Labrador Sea|author=Kenneth F. Drinkwater, R. Allyn Clarke|encyclopedia=The Canadian Encyclopedia|access-date=2008-02-03|archive-date=2018-08-02|archive-url=https://web.archive.org/web/20180802162457/https://www.thecanadianencyclopedia.com/en/article/labrador-sea/|url-status=live}}</ref> The speed of the Labrador current is typically {{Convert|0.3|-|0.5|m/s|abbr=on}}, but can reach {{Convert|1|m/s|abbr=on}} in some areas,<ref>{{cite journal|author1=Petrie, B. |author2=A. Isenor |year=1985 |title=The near-surface circulation and exchange in the Newfoundland Grand Banks region |journal=Atmosphere-Ocean |volume=23 |issue=3 |pages=209–227 |doi=10.1080/07055900.1985.9649225 |doi-access=free |bibcode=1985AtO....23..209P }}</ref> whereas the Baffin Current is somewhat slower at about {{Convert|0.2|m/s|abbr=on}}.<ref>{{cite web|url=http://www.britannica.com/EBchecked/topic/48703/Baffin-Island-Current|title=Baffin Current|author=Encyclopædia Britannica|author-link=Encyclopædia Britannica|access-date=2010-02-03}}</ref> The Labrador Current maintains the water temperature at {{Convert|0|C}} and salinity between 30 and 34 parts per thousand.<ref>{{cite web|url=http://www.britannica.com/EBchecked/topic/327001/Labrador-Current|title=Labrador Current|author=Encyclopædia Britannica|author-link=Encyclopædia Britannica|access-date=2010-02-03}}</ref>

The sea provides a significant part of the [[North Atlantic Deep Water]] (NADW) — a cold water mass that flows at great depth along the western edge of the North Atlantic, spreading out to form the largest identifiable water mass in the [[World Ocean]].<ref>{{cite book|url=https://books.google.com/books?id=JMI6AAAAIAAJ&pg=PA179|page=179|title=Earth systems: processes and issues|author=Wallace Gary Ernst|publisher=[[Cambridge University Press]]|year=2000|isbn=0-521-47895-2}}</ref> The NADW consists of three parts of different origin and salinity, and the top one, the Labrador Sea Water (LSW), is formed in the Labrador Sea. This part occurs at a medium depth and has a relatively low salinity (34.84–34.89 parts per thousand), low temperature ({{Convert|3.3|-|3.4|C|F|1}}) and high oxygen content compared to the layers above and below it. LSW also has a relatively low vorticity, i.e. the tendency to form vortices, than any other water in North Atlantic that reflects its high homogeneity. It has a [[potential density]] of 27.76–27.78&nbsp;mg/cm<sup>3</sup> relatively to the surface layers, meaning it is denser, and thus sinks under the surface and remains homogeneous and unaffected by the surface fluctuations.<ref>{{Cite FTP |last1=Talley|first1=L.D.|last2=McCartney|first2=M.S.|title=Distribution and Circulation of Labrador Sea Water|doi=10.1175/1520-0485(1982)012<1189:DACOLS>2.0.CO;2|issn=1520-0485|year=1982|page=1189|volume=12|url=ftp://gyre.ucsd.edu/nonpub/talley/papers/1980s/talley_mccartney_jpo_1982.pdf|issue=11|server=Journal of Physical Oceanography|url-status=dead|bibcode=1982JPO....12.1189T}}</ref>