We present an analysis of the interaction between wind‐driven and thermohaline‐driven circulations in a coarse‐resolution global ocean general circulation model of the Bryan‐Cox code. A series of experiments is described in which the flow is driven by wind forcing only, thermohaline forcing only, or both. In a global ocean with topography, the circulation driven by wind alone is strongly influenced by contours of constant potential vorticity, which limit the barotropic transport to relatively small values. With the same geometry, the flow driven by relaxing to observed surface temperature and salinity fields alone contains deep overturning circulation (producing North Atlantic Deep Water and Antarctic Bottom Water (AABW)) and a large barotropic Antarctic Circumpolar Current (ACC) generated by bottom form stress. The ACC is dependent on the overturning circulation, the deep density field and the bottom form stress and increases with A TV , the vertical mixing coefficient. If wind is added to this flow, the additional circulation is also dependent on the baroclinic structure but decreases with increasing A TV . This applies especially to the ACC, where wind‐induced additions are much larger than when the wind acts alone in a homogeneous ocean. An analysis of the dynamic balance of the ACC in the model shows that it is governed by lateral friction, bottom form stress, and wind. The mechanism for driving the ACC by deep convection and bottom topography is revealed in special expe

deep ocean. The thermohaline circulation (THC) moves at speeds of 10-50 km yr'', driven by water masses … masses of different densities determined by temperature and salinity properties. It is isolated from the surface … by Earth’s wind belts. A thermohaline circulation exists at depth, driven by buoyancy differences influenced

The ocean thermohaline circulation is often referred to as a global conveyor (Gordon 1986; Broecker and Denton 1989; Broecker 1991; review in Gordon et al. 1992). It is common knowledge that the global ocean thermohaline circulation is strongly controlled by the production of the North Atlantic Deep Water (NADW). Warm and salty subtropical water is carried to the high latitudes in the North Atlantic (NA) by the North Atlantic Current. It is cooled there and descends to set forth the deep ocean current system which is believed to be a global feature, a conveyor. Since the conveyor is mainly driven by latitudinal density gradients, which in high latitudes are controlled primarily by salinity, the density-driven conveyor is also referred to as the global salinity conveyor belt (Broecker 1991). The intriguing part of the problem is that the driving mechanism of change is thought to be very localized, with the key area of convection in the northern NA being surprisingly small with respect to the global ocean volume.

Buoyancy forcing in the subpolar North Atlantic Ocean (SPNA) is an important driver of the Atlantic Meridional Overturning Circulation (AMOC). To advance understanding of the mechanisms connecting the two processes and their relative importance in sub-basins within the SPNA, we apply the Water Mass Transformation Framework to a matched-pair of forced, ocean-sea ice simulations configured at eddying and non-eddying resolution. Within the first decade of simulation, the non-eddying simulation produces a weak AMOC, ~11 Sv at 26.5 ° N, while the AMOC in the eddying simulation is more realistic and is thus analyzed for comparison. Surface water mass transformation and boundary transport are calculated in both density and temperature–salinity coordinates in three separate deep water formation regions, the Iceland Basin, the Irminger Sea and Labrador Sea, during the first decade of both simulations. We identify strong surface freshening in the Irminger and Labrador seas in the non-eddying simulation during the AMOC decline. This freshening significantly reduces the density of the surface outcrops where surface water mass formation occurs, essentially removing this contribution to deep water formation. Concurrently, boundary transports in these two regions are warmer and saltier in the non-eddying simulation compared to the eddying simulation where the density of surface water mass formation is stable. The warming and salinification of boundary transports in the non-eddying simulatio

by gradients in water density, which in turn depend on variations in temperature and salinity. This thermohaline circulation is also known as the ocean's An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, shoreline configurations, and interactions with other currents influence a current's direction and strength. Ocean currents move both horizontally, on scales t L…

Turbidity currents are flows driven by density differences caused by suspended sediment. They … slicks caused by chemical accumulations and other smooth surface regions caused by strong … hydraulic behavior with density currents driven by temperature and salinity inhomogeneities. Whereas

Water mass transformation in the Southern Ocean is vital for driving the large-scale overturning circulation, which transports heat from the surface to the ocean interior. Using profiling gliders, this study investigates the role of summertime buoyancy forcing and wind-driven processes on the intraseasonal (1–10 days) mixed layer thermohaline variability in three Southern Ocean regions southwest of Africa important for water mass transformation—the Subantarctic Zone (SAZ), Polar Frontal Zone (PFZ), and Marginal Ice Zone (MIZ). At intraseasonal time scales, heat flux was shown as the main drive

The multiple equilibria of the thermohaline circulation (THC: used here in the sense of the meridional overturning circulation) as function of the surface freshwater flux has been studied intensively following a Stommel paper from 1961. It is shown here that multistability and hysteresis of the THC also exist when the wind stress amplitude is varied as a control parameter. Both the Massachusetts Institute of Technology ocean general circulation model (MITgcm) and a simple three-box model are used to study and explain different dynamical regimes of the THC and THC variability as a function of t

This article offers a concise account of the known science underpinning the greenhouse effect and global warming. The greenhouse effect is described at different levels of sophistication. It explains how greenhouse gases work and their relative contribution to warming. Climate models are introduced, as are climate sensitivity, feedback mechanisms and uncertainties. It explains how disruption of the thermohaline circulation could make Europe colder in a warmer world. Global warming sceptics are discussed. The role of political bodies like the IPCC is described, as are the main ways we can respo

RAPID was a 6 year (2001-2007) 'Directed Mode' research programme of the Natural Environment Research Council (NERC) to study the liklihood of changes occuring in the North Atlantic Thermohaline Circulation (THC)

The surface circulation of the world’s oceans is mostly wind driven . Thermohaline currents are driven by differences in heat and salt and are associated

vertical circulation in the oceans (in the form of currents like the thermohaline discussed in 5.2.2) means that there is a strong circulation between