Lincoln Sea(French:Mer de Lincoln;Danish:Lincolnhavet) is a body of water in theArctic Ocean,stretching fromCape Columbia,Canada,in the west toCape Morris Jesup,Greenland,in the east. The northern limit is defined as thegreat circleline between those twoheadlands.It is covered withsea icethroughout the year, the thickest sea ice in the Arctic Ocean, which can be up to 15 m (49 ft) thick. Water depths range from 100 m (330 ft) to 300 m (980 ft). Water and ice from Lincoln Sea empty intoRobeson Channel,the northernmost part ofNares Strait,most of the time.
| Lincoln Sea | |
|---|---|
 Map of the Lincoln Sea | |
  Lincoln Sea | |
| Coordinates | 83°N58°W/ 83°N 58°W |
| Type | Sea |
| Basincountries | CanadaandGreenland |
| Surface area | 64,000 km2(25,000 sq mi) |
| Average depth | 257 m (843 ft) |
| Water volume | 16,000 km3(1.3×1010acre⋅ft) |
| Frozen | Practically all year round |
| References | [1] |
The sea was named afterRobert Todd Lincoln,thenUnited States Secretary of War,onAdolphus W. Greely's 1881–1884 Arctic expedition intoLady Franklin Bay.[2]
Alert,the northernmost station of Canada, is the only populated place on the shore of Lincoln Sea.
The body of water to the east of Lincoln Sea (east of Cape Morris Jesup) is theWandel Sea.
Currents and Oceanic Circulation
editBecause of the severe ice conditions that last year-round, oceanographic measurements of the Lincoln Sea have been all but impossible. Before the 1980s, only low-flying aircraft samplings and ground observations from ice islands could be attempted; these did not stray far from the shores ofGreenlandand theCanadian Arctic Archipelagodue to the harsh environment. Between 1989 and 1994, the field experiments in Project Spinnaker were underway, implementing instrumentation that capturedtemperatureandsalinityprofiles well into the heart of the Lincoln Sea. Taken just east of where the North American continent intersects theLomonosov Ridge,these observations revealed the oceanographic features and current formations within and surrounding the Lincoln Sea.
Along the continental margins of theArctic Oceanbasin, narrow boundary currents are hypothesized to house intense large-scale advection that is critical in the general circulation of Arctic waters. From theBering Strait,Pacific Oceanwaters flow counterclockwise (cyclonically) along the northern shores ofCanada,passing through the Lincoln Sea.Atlantic Oceanwaters cyclonically flow in from and return to the Eurasian basin along theGreenland Seacontinental slope. The waters of these basins converge at the Lincoln Sea, creating unique vertical temperature and salinity profiles here. Measurements detail that both the Pacific and Eurasian Ocean water profiles are clearly offset from one another, an important facet of thehydrographyof the Lincoln Sea.
The Lincoln Sea has been found to contain water with three distinct properties. The first concerns the water in the inner part of the Lincoln Sea shelf, where the temperature and salinity profiles increase from the surface to the seafloor. The second involves the water covering the outer part of the shelf, including the slope; the waters here hold attributes similar to those in the Canadian basin and thus not unlike those from the Pacific. The third includes the waters north of the shelf's slope. These waters protrude into the Arctic basin's large-scale circulation, and so their characteristics appear to change over to those found in the Eurasian basin.
Along the continental margins of the Arctic Ocean basin, narrowboundary currentsare hypothesized to house intense large-scaleadvectionthat is critical in the general circulation of Arctic waters. One of these boundary currents resides along the sloping edge of the Lincoln Sea shelf, between the base and the shelf break at approximately 1600 m. The current's strength is 5–6 cm/s, according to long-term measurements. Assuming an undercurrent with an average strength of 4 cm/s and dimensions of 50 km in length and 1000 m in depth, the transport delivered over the slope of the Lincoln Sea shelf would be 2Sverdrups,where 1 Sverdrup equals 10^6 m^3/s. Measurements reveal that this undercurrent shares comparable features to that found in theBeaufort Sea,whose boundary currents are responsible for large-scale advection within the Arctic circulation. Because of this mutual oceanographic behavior, it has been determined that the Lincoln Sea undercurrent continuously flows and is a component of the boundary current system that spans betweenAlaskaandGreenlandalong the northern shores of the Canadian archipelago.[3]
Sea Ice
editIn May 2004 and 2005,electromagneticmeasurements from helicopters revealed insights into the thickness of thesea icein the Lincoln Sea and surrounding waters. With thicknesses ranging between 3.9 and 4.2 m,multi-year icedominates south of 84°N.First-year ice,with thicknesses ranging between 0.9 and 2.2 m, denotes the refreezing of the Lincoln Polynya ice. These helicopter measurements concur with satellite-based radar imagery as well as ground-based electromagnetic observations. Drifting buoys have exposed a southward drift of sea ice towardEllesmere IslandandNares Strait.It has been concluded thatshearin the Lincoln Sea narrow boundary current plays an important role in shifting and thus removing sea ice from the Arctic region.[4]
The majority of sea ice export takes place on the eastern edges of the Arctic Ocean circulation near Greenland through theFram Strait.Sea ice export through the Canadian archipelago was originally assumed to be zero, but that is not the case. The Lincoln Sea contains very thick multi-year sea ice, and so was thought to be stationary because of the apparent lack of oceanic outlets. However, according to a Canadian sea ice study, an area of approximately 22500 km2of multi-year sea ice is drained through the Nares Strait each year. During theNorthern Hemispherewinter,an area of about 225 km2of ice reforms, resulting in 335 km2of total sea ice drainage. Although this represents only one of the many pathways from the Arctic Ocean basin through the Canadian archipelago, "…this [total drainage] is an order of magnitude less than thefluxof sea ice out of [the] Fram Strait. "[5]
Dispute
editA disagreement over a 200-square-kilometre section of the Lincoln Sea emerged after 1973 when Canada and Denmark signed a treaty[6]establishing the offshore boundary north of Canada'sEllesmere IslandandDanish-controlledGreenlandbut left portions of it undefined.
From Canada's point of view, the point of focus in the Lincoln Sea dispute has been Denmark's inclusion ofBeaumont Island (Greenland)(not to be confused withBeaumont Islandoff the west coast ofGraham Land,Antarctica) off Greenland's northwest coast in calculating the boundary. The boundary is determined in that region by an "equidistance" principle that draws the line halfway between points along each country's coastline. Canada has basically argued that Beaumont Island is too insignificant to be used by Greenland to help determine the international boundary.[7]
In 2022, Canada and Denmark formalized the maritime boundary between Nunavut and Greenland, including in the Lincoln Sea, and establishing a land border onHans Island.[8]
Extent
editTheInternational Hydrographic Organizationdefines the limits of the Lincoln Sea as follows:[9]
On the North.Cape ColumbiatoCape Morris Jesup(Greenland).
On the South.Cape Columbia through Northeastern shore ofEllesmere IslandtoCape SheridantoCape Bryant(Greenland) through Greenland to Cape Morris Jesup.
References
edit- ^R. Stein,Arctic Ocean Sediments: Processes, Proxies, and Paleoenvironment,p. 37
- ^"Lincoln Sea, a sea in the Arctic Ocean".deepseawaters, Phoenix, Arizona. 2012.Retrieved17 July2012.
- ^Newton, John L.; Sotirin, Barbara J. (1997)."Boundary undercurrent and water mass changes in the Lincoln Sea".Journal of Geophysical Research: Oceans.102(C2): 3393–3403.Bibcode:1997JGR...102.3393N.doi:10.1029/96JC03441.
- ^"Comparison of the sea-ice thickness distribution in the Lincoln Sea and adjacent Arctic Ocean in 2004 and 2005".International Glaciological Society. 2006.Retrieved9 November2013.[permanent dead link]
- ^"Drainage of multi-year sea ice from the Lincoln Sea"(PDF).World Climate Research Program. 1998. Archived fromthe original(PDF)on 2013-11-11.Retrieved10 November2013.
- ^"Canada and Kingdom of Denmark Reach Tentative Agreement on Lincoln Sea Boundary Backgrounder".Foreign Affairs and International Trade Canada. 2012. Archived fromthe originalon 22 February 2014.Retrieved16 February2014.
- ^"Canada, Denmark start talks to resolve border dispute"(PDF).Edmonton Journal. 2010. Archived fromthe original(PDF)on 12 May 2013.Retrieved19 June2012.
- ^"Boundary dispute Backgrounder".Global Affairs Canada. 2022.Retrieved14 June2022.
- ^"Limits of Oceans and Seas, 3rd edition"(PDF).International Hydrographic Organization. 1953. Archived fromthe original(PDF)on 8 October 2011.Retrieved28 December2020.