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
Bifurcations of the Atlantic thermohaline circulation in response to changes in the hydrological cycle
TL;DR: In this paper, the sensitivity of the North Atlantic thermohaline circulation to the input of fresh water is studied using a global ocean circulation model coupled to a simplified model atmosphere, showing that moderate changes in freshwater input can induce transitions between different equilibrium states, leading to substantial changes in regional climate.
Journal ArticleDOI
Thermohaline Convection with Two Stable Regimes of Flow
TL;DR: Free convection between two interconnected reservoirs, due to density differences maintained by heat and salt transfer to the reservoirs, is shown to occur sometimes in two different stable regimes, and may possibly be analogous to certain features of the oseanic circulation as discussed by the authors.
Journal ArticleDOI
High-latitude salinity effects and interhemispheric thermohaline circulations
Frank O. Bryan,Frank O. Bryan +1 more
TL;DR: In this paper, a general circulation model for the ocean is used to investigate the interaction between the global-scale thermohaline circulation and the salinity distribution, and multiple equilibrium solutions are obtained for the same forcing by perturbing the high-latitude salinity field in an otherwise equatorially symmetric initial condition.
Journal ArticleDOI
Changes in East Atlantic Deepwater Circulation over the last 30,000 years: Eight time slice reconstructions
Michael Sarnthein,Kyaw Winn,Simon Jung,Jean-Claude Duplessy,Laurent Labeyrie,Helmut Erlenkeuser,Gerald Ganssen +6 more
TL;DR: Using 95 epibenthic δ13C records, eight time slices were reconstructed to trace the distribution of east Atlantic deepwater and intermediate water masses over the last 30,000 years as discussed by the authors.
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