Journal ArticleDOI
On the freshwater forcing and transport of the Atlantic thermohaline circulation
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In this article, it is argued that the freshwater loss to the atmosphere arises mainly in the subtropical South Atlantic and is balanced by northward freshwater transport in the wind-driven sub-tropical gyre, while the thermohaline circulation transports freshwater southward.Abstract:
The 'conveyor belt' circulation of the Atlantic Ocean transports large amounts of heat northward, acting as a heating system for the northern North Atlantic region. It is widely thought that this circulation is driven by atmospheric freshwater export from the Atlantic catchment region, and that it transports freshwater northward to balance the loss to the atmosphere. Using results from a simple conceptual model and a global circulation model, it is argued here that the freshwater loss to the atmosphere arises mainly in the subtropical South Atlantic and is balanced by northward freshwater transport in the wind-driven subtropical gyre, while the thermohaline circulation transports freshwater southward. It is further argued that the direction of freshwater transport is closely linked to the dynamical regime and stability of the 'conveyor belt': if its freshwater transport is indeed southward, then its flow is purely thermally driven and inhibited by the freshwater forcing. In this case the circulation is not far from Stommel's saddle-node bifurcation, and a circulation state without NADW formation would also be stable.read more
Citations
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Journal ArticleDOI
Constraints on future changes in climate and the hydrologic cycle
Myles R. Allen,William Ingram +1 more
TL;DR: It will be substantially harder to quantify the range of possible changes in the hydrologic cycle than in global-mean temperature, both because the observations are less complete and because the physical constraints are weaker.
Journal ArticleDOI
Increasing river discharge to the Arctic Ocean
Bruce J. Peterson,Robert M. Holmes,James W. McClelland,Charles J. Vörösmarty,Richard B. Lammers,Alexander I. Shiklomanov,Igor A. Shiklomanov,Stefan Rahmstorf +7 more
TL;DR: Synthesis of river-monitoring data reveals that the average annual discharge of fresh water from the six largest Eurasian rivers to the Arctic Ocean increased by 7% from 1936 to 1999, a large-scale change in freshwater flux.
Journal ArticleDOI
Forcing of the cold event of 8,200 years ago by catastrophic drainage of Laurentide lakes
Donald C. Barber,Arthur S. Dyke,Claude Hillaire-Marcel,Anne E. Jennings,John T. Andrews,M. W. Kerwin,G Bilodeau,Roger McNeely,John R. Southon,Mark D. Morehead,Jean-Marc Gagnon +10 more
TL;DR: In this article, the authors argue that this cooling event was forced by a massive outflow of fresh water from the Hudson Strait, based on the estimates of the marine 14C reservoir for Hudson Bay which, in combination with other regional data, indicate that the glacial lakes Agassiz and Ojibway (originally dammed by a remnant of the Laurentide ice sheet) drained catastrophically ∼8,470 calendar years ago; this would have released >1014 m3 of freshwater into the Labrador Sea.
Journal ArticleDOI
Rapid changes of glacial climate simulated in a coupled climate model.
TL;DR: It is found that only one mode of Atlantic Ocean circulation is stable: a cold mode with deep water formation in the Atlantic Ocean south of Iceland; this provides an explanation why glacial climate is much more variable than Holocene climate.
Journal ArticleDOI
Ocean circulation and climate during the past 120,000 years
TL;DR: Evidence implicates ocean circulation in abrupt and dramatic climate shifts, such as sudden temperature changes in Greenland on the order of 5–10 °C and massive surges of icebergs into the North Atlantic Ocean.
References
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Journal ArticleDOI
Rapid climate transitions in a coupled ocean–atmosphere model
TL;DR: In this article, the authors present simulations with a three-dimensional ocean model coupled to an idealized atmosphere, which show this kind of transition and the mechanism for the transition is a rearrangement of convection in the North Atlantic, triggered by a brief freshwater pulse.
Journal ArticleDOI
Evaporation Minus Precipitation and Density Fluxes for the North Atlantic
TL;DR: In this article, estimates of evaporation (E) over the North Atlantic Ocean by Bunker have been combined with estimates of precipitation (P) by Dorman and Bourke to produce new annual and seasonal maps of E-P and surface density flux.
Journal ArticleDOI
Stability and Variability of the Thermohaline Circulation
TL;DR: In this article, the stability and internal variability of the ocean's thermohaline circulation were investigated using a coarse-resolution general circulation model of an idealized ocean basin, in one hemisphere.
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