Journal articles: 'Wind driven ocean circulation'

1

Lee, Dong-Kyu, Peter Niiler, Alex Warn-Varnas, and Steve Piacsek. "Wind-driven secondary circulation in ocean mesoscale." Journal of Marine Research 52, no. 3 (May 1, 1994): 371–96. http://dx.doi.org/10.1357/0022240943077037.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Geshelin, Yuri S. "Thermally driven wind circulation near ocean fronts." Physics and Chemistry of the Earth 23, no. 5-6 (January 1998): 605–7. http://dx.doi.org/10.1016/s0079-1946(98)00082-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Marshall, David P., and Helen R. Pillar. "Momentum Balance of the Wind-Driven and Meridional Overturning Circulation." Journal of Physical Oceanography 41, no. 5 (May 1, 2011): 960–78. http://dx.doi.org/10.1175/2011jpo4528.1.

Full text

Abstract:

Abstract When a force is applied to the ocean, fluid parcels are accelerated both locally, by the applied force, and nonlocally, by the pressure gradient forces established to maintain continuity and satisfy the kinematic boundary condition. The net acceleration can be represented through a “rotational force” in the rotational component of the momentum equation. This approach elucidates the correspondence between momentum and vorticity descriptions of the large-scale ocean circulation: if two terms balance pointwise in the rotational momentum equation, then the equivalent two terms balance pointwise in the vorticity equation. The utility of the approach is illustrated for three classical problems: barotropic Rossby waves, wind-driven circulation in a homogeneous basin, and the meridional overturning circulation in an interhemispheric basin. In the hydrostatic limit, it is shown that the rotational forces further decompose into depth-integrated forces that drive the wind-driven gyres and overturning forces that are confined to the basin boundaries and drive the overturning circulation. Potential applications of the approach to diagnosing the output of ocean circulation models, alternative and more accurate formulations of numerical ocean models, the dynamics of boundary layer separation, and eddy forcing of the large-scale ocean circulation are discussed.

APA, Harvard, Vancouver, ISO, and other styles

4

Swart, N. C., J. C. Fyfe, O. A. Saenko, and M. Eby. "Wind driven changes in the ocean carbon sink." Biogeosciences Discussions 11, no. 6 (June 4, 2014): 8023–48. http://dx.doi.org/10.5194/bgd-11-8023-2014.

Full text

Abstract:

Abstract. We estimate the historical ocean carbon sink over 1871 to 2010 using an ocean biogeochemical model driven with observed wind forcing. We focus on the influence of wind and mesoscale eddy changes on the net surface CO2 flux, which are most significant after 1950. The observed wind changes act to reduce the annual ocean carbon sink by 0.009 to 0.023 Pg yr−1 decade−1 over 1950 to 2010, and are consistent with previous studies covering only the latter part of the 20th century. The response of the ocean circulation and the carbon cycle to wind changes is sensitive to the parameterization of mesoscale eddies in our coarse resolution simulations. With a variable eddy transfer coefficient, eddy activity in the Southern Ocean increases in response to intensifying historical winds, partially compensating for direct wind-driven circulation changes. Thus with a variable eddy transfer coefficient the response to wind changes is about 2.5 times smaller than when using a constant coefficient. Finally, we show by comparing six reanalyses over 1980 to 2010 that estimated historical wind trends differ significantly. Through simulations forced with these reanalysis winds we show that the influence of historical wind changes on ocean carbon uptake is highly uncertain and depends on the choice of surface wind forcing product.

APA, Harvard, Vancouver, ISO, and other styles

5

Döös, K. "The wind-driven overturning circulation of the World Ocean." Ocean Science Discussions 2, no. 5 (November 25, 2005): 473–505. http://dx.doi.org/10.5194/osd-2-473-2005.

Full text

Abstract:

Abstract. The wind driven aspects of the meridional overturning circulation of the world ocean and the Conveyor Belt is studied making use of a simple analytical model. The model consists of three reduced gravity layers with an inviscid Sverdrupian interior and a western boundary layer. The net north-south exchange is made possible by setting appropriate western boundary conditions, so that most of the transport is confined to the western boundary layer, while the interior is the Sverdrupian solution to the wind stress. The flow across the equator is made possible by the change of potential vorticity by the Rayleigh friction in the western boundary layer, which is sufficient to permit water and the Conveyor Belt to cross the equator. The cross-equatorial flow is driven by a weak meridional pressure gradient in opposite direction in the two layers on the equator at the western boundary. The model is applied to the World Ocean with a realistic wind stress. The amplitude of the Conveyor Belt is set by the northward Ekman transport in the Southern Ocean and the outcropping latitude of the NADW. It is in this way possible to set the amount of NADW that is pumped up from the deep ocean and driven northward by the wind and converted in the surface layer into less dense water by choosing the outcropping latitude and the depth of the layers at the western boundary. The model has proved to be able to simulate many of the key features of the Conveyor Belt and the meridional overturning cells of the World Ocean. This despite that there is no deep ocan mixing and that the water mass conversions in the this model are made at the surface.

APA, Harvard, Vancouver, ISO, and other styles

6

Matisoff, Gerald. "Models of Wind-Driven and Thermohaline Ocean Circulation." Journal of Geological Education 43, no. 2 (March 1995): 133–37. http://dx.doi.org/10.5408/0022-1368-43.2.133.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Griffa, Annalisa, and Rick Salmon. "Wind-driven ocean circulation and equilibrium statistical mechanics." Journal of Marine Research 47, no. 3 (August 1, 1989): 457–92. http://dx.doi.org/10.1357/002224089785076235.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Provost, Christian Le, and Jacques Verron. "Wind-driven ocean circulation transition to barotropic instability." Dynamics of Atmospheres and Oceans 11, no. 2 (September 1987): 175–201. http://dx.doi.org/10.1016/0377-0265(87)90005-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Wang, Guihua, Rui Xin Huang, Jilan Su, and Dake Chen. "The Effects of Thermohaline Circulation on Wind-Driven Circulation in the South China Sea." Journal of Physical Oceanography 42, no. 12 (December 1, 2012): 2283–96. http://dx.doi.org/10.1175/jpo-d-11-0227.1.

Full text

Abstract:

Abstract The dynamic influence of thermohaline circulation on wind-driven circulation in the South China Sea (SCS) is studied using a simple reduced gravity model, in which the upwelling driven by mixing in the abyssal ocean is treated in terms of an upward pumping distributed at the base of the upper layer. Because of the strong upwelling of deep water, the cyclonic gyre in the northern SCS is weakened, but the anticyclonic gyre in the southern SCS is intensified in summer, while cyclonic gyres in both the southern and northern SCS are weakened in winter. For all seasons, the dynamic influence of thermohaline circulation on wind-driven circulation is larger in the northern SCS than in the southern SCS. Analysis suggests that the upwelling associated with the thermohaline circulation in the deep ocean plays a crucial role in regulating the wind-driven circulation in the upper ocean.

APA, Harvard, Vancouver, ISO, and other styles

10

Veronis, George. "Effect of a Constant, Zonal Wind on Wind-Driven Ocean Circulation." Journal of Physical Oceanography 26, no. 11 (November 1996): 2525–28. http://dx.doi.org/10.1175/1520-0485(1996)026<2525:eoaczw>2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Nikurashin, Maxim, and Geoffrey Vallis. "A Theory of the Interhemispheric Meridional Overturning Circulation and Associated Stratification." Journal of Physical Oceanography 42, no. 10 (May 19, 2012): 1652–67. http://dx.doi.org/10.1175/jpo-d-11-0189.1.

Full text

Abstract:

Abstract A quantitative theoretical model of the meridional overturning circulation and associated deep stratification in an interhemispheric, single-basin ocean with a circumpolar channel is presented. The theory includes the effects of wind, eddies, and diapycnal mixing and predicts the deep stratification and overturning streamfunction in terms of the surface forcing and other parameters of the problem. It relies on a matching among three regions: the circumpolar channel at high southern latitudes, a region of isopycnal outcrop at high northern latitudes, and the ocean basin between. The theory describes both the middepth and abyssal cells of a circulation representing North Atlantic Deep Water and Antarctic Bottom Water. It suggests that, although the strength of the middepth overturning cell is primarily set by the wind stress in the circumpolar channel, middepth stratification results from a balance between the wind-driven upwelling in the channel and deep-water formation at high northern latitudes. Diapycnal mixing in the ocean interior can lead to warming and upwelling of deep waters. However, for parameters most representative of the present ocean mixing seems to play a minor role for the middepth cell. In contrast, the abyssal cell is intrinsically diabatic and controlled by a balance between the deep mixing-driven upwelling and the residual of the wind-driven and eddy-induced circulations in the Southern Ocean. The theory makes explicit predictions about how the stratification and overturning circulation vary with the wind strength, diapycnal diffusivity, and mesoscale eddy effects. The predictions compare well with numerical results from a coarse-resolution general circulation model.

APA, Harvard, Vancouver, ISO, and other styles

12

Barrier, Nicolas, Christophe Cassou, Julie Deshayes, and Anne-Marie Treguier. "Response of North Atlantic Ocean Circulation to Atmospheric Weather Regimes." Journal of Physical Oceanography 44, no. 1 (January 1, 2014): 179–201. http://dx.doi.org/10.1175/jpo-d-12-0217.1.

Full text

Abstract:

Abstract A new framework is proposed for investigating the atmospheric forcing of North Atlantic Ocean circulation. Instead of using classical modes of variability, such as the North Atlantic Oscillation (NAO) or the east Atlantic pattern, the weather regimes paradigm was used. Using this framework helped avoid problems associated with the assumptions of orthogonality and symmetry that are particular to modal analysis and known to be unsuitable for the NAO. Using ocean-only historical and sensitivity experiments, the impacts of the four winter weather regimes on horizontal and overturning circulations were investigated. The results suggest that the Atlantic Ridge (AR), negative NAO (NAO−), and positive NAO (NAO+) regimes induce a fast (monthly-to-interannual time scales) adjustment of the gyres via topographic Sverdrup dynamics and of the meridional overturning circulation via anomalous Ekman transport. The wind anomalies associated with the Scandinavian blocking regime (SBL) are ineffective in driving a fast wind-driven oceanic adjustment. The response of both gyre and overturning circulations to persistent regime conditions was also estimated. AR causes a strong, wind-driven reduction in the strengths of the subtropical and subpolar gyres, while NAO+ causes a strengthening of the subtropical gyre via wind stress curl anomalies and of the subpolar gyre via heat flux anomalies. NAO− induces a southward shift of the gyres through the southward displacement of the wind stress curl. The SBL is found to impact the subpolar gyre only via anomalous heat fluxes. The overturning circulation is shown to spin up following persistent SBL and NAO+ and to spin down following persistent AR and NAO− conditions. These responses are driven by changes in deep water formation in the Labrador Sea.

APA, Harvard, Vancouver, ISO, and other styles

13

Shen, Hui, William Perrie, and Yongsheng Wu. "Wind drag in oil spilled ocean surface and its impact on wind-driven circulation." Anthropocene Coasts 2, no. 1 (January 1, 2019): 244–60. http://dx.doi.org/10.1139/anc-2018-0019.

Full text

Abstract:

The drag coefficient is a key parameter to quantify the wind stress over the ocean surface, which depends on the ocean surface roughness. During oil spill events, oil slicks cover the ocean surface and thus change the surface roughness by suppressing multi-scale ocean surface waves, and the drag coefficient is changed. This change has not been included in the current ocean circulation models. In this study, such change in sea surface roughness is studied by satellite remote sensing via synthetic aperture radar (SAR) data to quantify the changes in the wind effect over the oil-covered ocean surface. The concept of effective wind speed is introduced to quantify the wind work on the ocean. We investigate its influence on the wind-driven Ekman current at the ocean surface. Using observations from the Deepwater Horizon oil spill (2010) as an example, we find that the presence of oil can result in an effective wind speed of 50%∼100% less than the conventional wind speed, causing overestimates by 75%∼100% in the wind driven Ekman current. The effect of such bias on oil trajectory predictions is also discussed. Our results suggest that it is important to consider the effect of changes in the drag coefficient over oil-contaminated areas, especially for large-scale oil spill situations.

APA, Harvard, Vancouver, ISO, and other styles

14

Wu, Yang, Xiaoming Zhai, and Zhaomin Wang. "Impact of Synoptic Atmospheric Forcing on the Mean Ocean Circulation." Journal of Climate 29, no. 16 (July 27, 2016): 5709–24. http://dx.doi.org/10.1175/jcli-d-15-0819.1.

Full text

Abstract:

Abstract The impact of synoptic atmospheric forcing on the mean ocean circulation is investigated by comparing simulations of a global eddy-permitting ocean–sea ice model forced with and without synoptic atmospheric phenomena. Consistent with previous studies, transient atmospheric motions such as weather systems are found to contribute significantly to the time-mean wind stress and surface heat loss at mid- and high latitudes owing to the nonlinear nature of air–sea turbulent fluxes. Including synoptic atmospheric forcing in the model has led to a number of significant changes. For example, wind power input to the ocean increases by about 50%, which subsequently leads to a similar percentage increase in global eddy kinetic energy. The wind-driven subtropical gyre circulations are strengthened by about 10%–15%, whereas even greater increases in gyre strength are found in the subpolar oceans. Deep convection in the northern North Atlantic becomes significantly more vigorous, which in turn leads to an increase in the Atlantic meridional overturning circulation (AMOC) by as much as 55%. As a result of the strengthened horizontal gyre circulations and the AMOC, the maximum global northward heat transport increases by almost 50%. Results from this study show that synoptic atmospheric phenomena such as weather systems play a vital role in driving the global ocean circulation and heat transport, and therefore should be properly accounted for in paleo- and future climate studies.

APA, Harvard, Vancouver, ISO, and other styles

15

Proshutinsky, A. Y., and M. A. Johnson. "Two circulation regimes of the wind-driven Arctic Ocean." Journal of Geophysical Research: Oceans 102, no. C6 (June 15, 1997): 12493–514. http://dx.doi.org/10.1029/97jc00738.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

De Szoeke, Roland A. "A Model of Wind- and Buoyancy-Driven Ocean Circulation." Journal of Physical Oceanography 25, no. 5 (May 1995): 918–41. http://dx.doi.org/10.1175/1520-0485(1995)025<0918:amowab>2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Sakamoto, Toshihiro. "Determination of wind-driven ocean circulation inside closed characteristics." Geophysical & Astrophysical Fluid Dynamics 94, no. 3-4 (July 2001): 151–76. http://dx.doi.org/10.1080/03091920108203406.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Desjardins, B., and E. Grenier. "On the Homogeneous Model of Wind-Driven Ocean Circulation." SIAM Journal on Applied Mathematics 60, no. 1 (January 1999): 43–60. http://dx.doi.org/10.1137/s0036139997324261.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Dijkstra, Henk A., and Will P. M. De Ruijter. "Finite amplitude stability of the wind-driven ocean circulation." Geophysical & Astrophysical Fluid Dynamics 83, no. 1-2 (November 1996): 1–31. http://dx.doi.org/10.1080/03091929608213640.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Swart, N. C., J. C. Fyfe, O. A. Saenko, and M. Eby. "Wind-driven changes in the ocean carbon sink." Biogeosciences 11, no. 21 (November 13, 2014): 6107–17. http://dx.doi.org/10.5194/bg-11-6107-2014.

Full text

Abstract:

Abstract. We estimate changes in the historical ocean carbon sink and their uncertainty using an ocean biogeochemical model driven with wind forcing from six different reanalyses and using two different eddy parameterization schemes. First, we quantify wind-induced changes over the extended period from 1871 to 2010 using the 20th Century Reanalysis winds. Consistent with previous shorter-term studies, we find that the wind changes act to reduce the ocean carbon sink, but the wind-induced trends are subject to large uncertainties. One major source of uncertainty is the parameterization of mesoscale eddies in our coarse resolution simulations. Trends in the Southern Ocean residual meridional overturning circulation and the globally integrated surface carbon flux over 1950 to 2010 are about 2.5 times smaller when using a variable eddy transfer coefficient than when using a constant coefficient in this parameterization. A second major source of uncertainty arises from disagreement on historical wind trends. By comparing six reanalyses over 1980 to 2010, we show that there are statistically significant differences in estimated historical wind trends, which vary in both sign and magnitude amongst the products. Through simulations forced with these reanalysis winds, we show that the influence of historical wind changes on ocean carbon uptake is highly uncertain, and the resulting trends depend on the choice of surface wind product.

APA, Harvard, Vancouver, ISO, and other styles

21

Salim, M., K. Nagendra, S. Bansal, R. K. Nayak, M. S. Rao, S. K. Sasmal, C. B. S. Dutt, K. H. Rao, and V. K. Dadhwal. "Assessment of OSCAT winds for coastal circulation on the north western continental shelf of India." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (November 28, 2014): 1073–77. http://dx.doi.org/10.5194/isprsarchives-xl-8-1073-2014.

Full text

Abstract:

Winds and tides are the major driving forces of the circulation in the coastal and marginal seas. Data Interpolating Variation Analysis (DIVA) method is used to generate spatial and time series data of sea surface winds for the period 2010–2013 at daily time scale from the OSCAT observations. Validity and consistency of the data were examined against the in situ observations and ECMWF re-analysis at different time scales. Amplitude of semi-annual cycle of OSCAT winds in the coastal domain is 30 % larger than the ECMWF winds while the amplitude of annual cycle of OSCAT winds is 20 % smaller than the ECMWF winds. On the open oceans, intensity of respective semi-annual cycles are mostly similar while annual cycle of OSCAT wind is 20 % smaller than the ECMWF winds. Wind driven currents over the western continental shelf of India were simulated by forcing OSCAT and ECMWF winds to a coastal circulation model. It is observed that the mean seasonal circulations from both the simulations are identical spatial pattern however the magnitude of simulated currents based on OSCAT winds are much stronger than ECMWF wind forcing. These currents used in a lagrangian tracer transport code to model the oil-spill events occurred in this region. It revealed that OSCAT based ocean currents has performed better in simulating the trajectory than the ECMWF wind driven currents.

APA, Harvard, Vancouver, ISO, and other styles

22

Zhao, Yu, Anmin Duan, Guoxiong Wu, and Ruizao Sun. "Response of the Indian Ocean to the Tibetan Plateau Thermal Forcing in Late Spring." Journal of Climate 32, no. 20 (September 16, 2019): 6917–38. http://dx.doi.org/10.1175/jcli-d-18-0880.1.

Full text

Abstract:

Abstract The thermal effect of the Tibetan Plateau (TP) is known to exert substantial impacts on the atmospheric general circulation, suggesting that it may also influence the wind-driven circulation in the ocean through air–sea interactions. Here, several coupled general circulation model experiments are performed in order to investigate the short-term response of the Indian Ocean to the TP surface heat source in late spring (May). The results indicate that positive TP heating anomalies can induce significant atmospheric circulation responses over the northern Indian Ocean, characterized by easterly anomalies in the upper troposphere due to the enhanced South Asian high and lower-level southwesterly anomalies from the heat pumping effect. As a result, the surface wind speed over the northern Indian Ocean is reinforced, leading to intensified oceanic evaporation and subsequently cooler potential temperatures in the mixed layer. Wind-driven currents in the mixed layer are also affected. In the Bay of Bengal, Ekman transport facilitates water volume movement from west to east. In the Arabian Sea, water movement is weaker and the southward component is relatively more important. Both these areas show local meridional circulations with offshore upwelling in the northwest. Moreover, the cross-equatorial current is also enhanced in the eastern part of the tropical Indian Ocean. Overall, the upper layer in the northern Indian Ocean is efficiently modulated by the TP thermal forcing within one month.

APA, Harvard, Vancouver, ISO, and other styles

23

Lodise, John, Tamay Özgökmen, Annalisa Griffa, and Maristella Berta. "Vertical structure of ocean surface currents under high winds from massive arrays of drifters." Ocean Science 15, no. 6 (December 9, 2019): 1627–51. http://dx.doi.org/10.5194/os-15-1627-2019.

Full text

Abstract:

Abstract. Very-near-surface ocean currents are dominated by wind and wave forcing and have large impacts on the transport of buoyant materials in the ocean. Surface currents, however, are under-resolved in most operational ocean models due to the difficultly of measuring ocean currents close to, or directly at, the air–sea interface with many modern instrumentations. Here, observations of ocean currents at two depths within the first meter of the surface are made utilizing trajectory data from both drogued and undrogued Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE) drifters, which have draft depths of 60 and 5 cm, respectively. Trajectory data of dense, colocated drogued and undrogued drifters were collected during the Lagrangian Submesoscale Experiment (LASER) that took place from January to March of 2016 in the northern Gulf of Mexico. Examination of the drifter data reveals that the drifter velocities become strongly wind- and wave-driven during periods of high wind, with the pre-existing regional circulation having a smaller, but non-negligible, influence on the total drifter velocities. During these high wind events, we deconstruct the total drifter velocities of each drifter type into their wind- and wave-driven components after subtracting an estimate for the regional circulation, which pre-exists each wind event. In order to capture the regional circulation in the absence of strong wind and wave forcing, a Lagrangian variational method is used to create hourly velocity field estimates for both drifter types separately, during the hours preceding each high wind event. Synoptic wind and wave output data from the Unified Wave INterface-Coupled Model (UWIN-CM), a fully coupled atmosphere, wave and ocean circulation model, are used for analysis. The wind-driven component of the drifter velocities exhibits a rotation to the right with depth between the velocities measured by undrogued and drogued drifters. We find that the average wind-driven velocity of undrogued drifters (drogued drifters) is ∼3.4 %–6.0 % (∼2.3 %–4.1 %) of the wind speed and is deflected ∼5–55∘ (∼30–85∘) to the right of the wind, reaching higher deflection angles at higher wind speeds. Results provide new insight on the vertical shear present in wind-driven surface currents under high winds, which have vital implications for any surface transport problem.

APA, Harvard, Vancouver, ISO, and other styles

24

Mahadevan, A., J. Lu, S. P. Meacham, and P. Malanotte-Rizzoli. "The predictability of large-scale wind-driven flows." Nonlinear Processes in Geophysics 8, no. 6 (December 31, 2001): 449–65. http://dx.doi.org/10.5194/npg-8-449-2001.

Full text

Abstract:

Abstract. The singular values associated with optimally growing perturbations to stationary and time-dependent solutions for the general circulation in an ocean basin provide a measure of the rate at which solutions with nearby initial conditions begin to diverge, and hence, a measure of the predictability of the flow. In this paper, the singular vectors and singular values of stationary and evolving examples of wind-driven, double-gyre circulations in different flow regimes are explored. By changing the Reynolds number in simple quasi-geostrophic models of the wind-driven circulation, steady, weakly aperiodic and chaotic states may be examined. The singular vectors of the steady state reveal some of the physical mechanisms responsible for optimally growing perturbations. In time-dependent cases, the dominant singular values show significant variability in time, indicating strong variations in the predictability of the flow. When the underlying flow is weakly aperiodic, the dominant singular values co-vary with integral measures of the large-scale flow, such as the basin-integrated upper ocean kinetic energy and the transport in the western boundary current extension. Furthermore, in a reduced gravity quasi-geostrophic model of a weakly aperiodic, double-gyre flow, the behaviour of the dominant singular values may be used to predict a change in the large-scale flow, a feature not shared by an analogous two-layer model. When the circulation is in a strongly aperiodic state, the dominant singular values no longer vary coherently with integral measures of the flow. Instead, they fluctuate in a very aperiodic fashion on mesoscale time scales. The dominant singular vectors then depend strongly on the arrangement of mesoscale features in the flow and the evolved forms of the associated singular vectors have relatively short spatial scales. These results have several implications. In weakly aperiodic, periodic, and stationary regimes, the mesoscale energy content is usually relatively low and the predictability of the wind-driven circulation is determined by the large-scale structure of the flow. In the more realistic, strongly chaotic regime, in which energetic mesoscale eddies are produced by the meandering of the separated western boundary current extension, the predictability of the flow locally tends to be a stronger function of the local mesoscale eddy structure than of the larger scale structure of the circulation. This has a broader implication for the effectiveness of different approaches to forecasting the ocean with models which sequentially assimilate new observations.

APA, Harvard, Vancouver, ISO, and other styles

25

Moore, Andrew M., Cristina L. Perez, and Javier Zavala-Garay. "A Non-normal View of the Wind-Driven Ocean Circulation." Journal of Physical Oceanography 32, no. 9 (September 1, 2002): 2681–705. http://dx.doi.org/10.1175/1520-0485-32.9.2681.

Full text

Abstract:

Abstract Generalized linear stability theory is applied to the wind-driven ocean circulation in the form of a double gyre described by the barotropic quasigeostrophic vorticity equation. The development of perturbations on this circulation is considered. The circulation fields are inhomogeneous, and regions of straining flow render non-normal the tangent linear operators that describe the time evolution of perturbation energy and enstrophy. When the double-gyre circulation is asymptotically stable, growth of perturbation energy and enstrophy is still possible due to linear interference of its nonorthogonal eigenmodes. The sources and sinks of perturbation energy and enstrophy associated with the interference process are traditionally associated with the interaction of perturbation stresses with the mean flow. These ideas are used to understand the response of an asymptotically stable double-gyre circulation to stochastic wind stress forcing. Calculation of the optimal forcing patterns (stochastic optimals) reveals that much of the stochastically induced variability can be explained by one pattern. Variability induced by this pattern is maintained by long and short Rossby waves that interact with the western boundary currents, and perturbation growth occurs through barotropic processes. The perturbations that maintain the stochastically induced variance in this way have a large projection on some of the most non-normal, least-damped eigenmodes of the double-gyre circulation. Perturbation growth in nonautonomous and asymptotically unstable systems is also considered in the same framework. The Lyapunov vectors of unstable flows are found to have a large projection on some of the most non-normal, least-damped eigenmodes of the time mean circulation.

APA, Harvard, Vancouver, ISO, and other styles

26

Chhak, Kettyah C., Andrew M. Moore, Ralph F. Milliff, Grant Branstator, William R. Holland, and Michael Fisher. "Stochastic Forcing of the North Atlantic Wind-Driven Ocean Circulation. Part I: A Diagnostic Analysis of the Ocean Response to Stochastic Forcing." Journal of Physical Oceanography 36, no. 3 (March 1, 2006): 300–315. http://dx.doi.org/10.1175/jpo2852.1.

Full text

Abstract:

Abstract At midlatitudes, the magnitude of stochastic wind stress forcing due to atmospheric weather is comparable to that associated with the seasonal cycle. Stochastic forcing is therefore likely to have a significant influence on the ocean circulation. In this work, the influence of the stochastic component of the wind stress forcing on the large-scale, wind-driven circulation of the North Atlantic Ocean is examined. To this end, a quasigeostrophic model of the North Atlantic was forced with estimates of the stochastic component of wind stress curl obtained from the NCAR Community Climate Model. Analysis reveals that much of the stochastically induced variability in the ocean circulation occurs in the vicinity of the western boundary and some major bathymetric features. Thus, the response is localized even though the stochastic forcing occurs over most of the ocean basin. Using the ideas of generalized stability theory, the stochastically induced response in the ocean circulation can be interpreted as a linear interference of the nonorthogonal eigenmodes of the system. This linear interference process yields transient growth of stochastically induced perturbations. By examining the model pseudospectra, it is seen that the nonnormal nature of the system enhances the transient growth of perturbation enstrophy and therefore elevates and maintains the variance of the stochastically induced circulations in the aforementioned regions. The primary causes of nonnormality in the enstrophy norm are bathymetry and the western boundary current circulation.

APA, Harvard, Vancouver, ISO, and other styles

27

Thomas, Leif N., and Craig M. Lee. "Intensification of Ocean Fronts by Down-Front Winds." Journal of Physical Oceanography 35, no. 6 (June 1, 2005): 1086–102. http://dx.doi.org/10.1175/jpo2737.1.

Full text

Abstract:

Abstract Many ocean fronts experience strong local atmospheric forcing by down-front winds, that is, winds blowing in the direction of the frontal jet. An analytic theory and nonhydrostatic numerical simulations are used to demonstrate the mechanism by which down-front winds lead to frontogenesis. When a wind blows down a front, cross-front advection of density by Ekman flow results in a destabilizing wind-driven buoyancy flux (WDBF) equal to the product of the Ekman transport with the surface lateral buoyancy gradient. Destabilization of the water column results in convection that is localized to the front and that has a buoyancy flux that is scaled by the WDBF. Mixing of buoyancy by convection, and Ekman pumping/suction resulting from the cross-front contrast in vertical vorticity of the frontal jet, drive frontogenetic ageostrophic secondary circulations (ASCs). For mixed layers with negative potential vorticity, the most frontogenetic ASCs select a preferred cross-front width and do not translate with the Ekman transport, but instead remain stationary in space. Frontal intensification occurs within several inertial periods and is faster the stronger the wind stress. Vertical circulation is characterized by subduction on the dense side of the front and upwelling along the frontal interface and scales with the Ekman pumping and convective mixing of buoyancy. Cross-front sections of density, potential vorticity, and velocity at the subpolar front of the Japan/East Sea suggest that frontogenesis by down-front winds was active during cold-air outbreaks and could result in strong vertical circulation.

APA, Harvard, Vancouver, ISO, and other styles

28

Hogg, Andrew Mc C., William K. Dewar, Peter D. Killworth, and Jeffrey R. Blundell. "Decadal Variability of the Midlatitude Climate System Driven by the Ocean Circulation." Journal of Climate 19, no. 7 (April 1, 2006): 1149–66. http://dx.doi.org/10.1175/jcli3651.1.

Full text

Abstract:

Abstract A midlatitude coupled ocean–atmosphere model is used to investigate interactions between the atmosphere and the wind-driven ocean circulation. This model uses idealized geometry, yet rich and complicated dynamic flow regimes arise in the ocean due to the explicit simulation of geostrophic turbulence. An interdecadal mode of intrinsic ocean variability is found, and this mode projects onto existing atmospheric modes of variability, thereby controlling the time scale of the atmospheric modes. It is also shown that ocean circulation controls the time scale of the SST response to wind forcing, and that coupled feedback mechanisms thus modify variability of the atmospheric circulation. It is concluded that ocean–atmosphere coupling in the midlatitudes is unlikely to produce new modes of variability but may control the temporal behavior of modes that exist in uncoupled systems.

APA, Harvard, Vancouver, ISO, and other styles

29

Green, Brian, and John Marshall. "Coupling of Trade Winds with Ocean Circulation Damps ITCZ Shifts." Journal of Climate 30, no. 12 (June 2017): 4395–411. http://dx.doi.org/10.1175/jcli-d-16-0818.1.

Full text

Abstract:

The position of the intertropical convergence zone (ITCZ) is sensitive to the atmosphere’s hemispheric energy balance, lying in the hemisphere most strongly heated by radiative and turbulent surface energy fluxes. This study examines how the ocean circulation, through its cross-equatorial energy transport and associated surface energy fluxes, affects the ITCZ’s response to an imposed interhemispheric heating contrast in a coupled atmosphere–ocean general circulation model. Shifts of the ITCZ are strongly damped owing to a robust coupling between the atmosphere’s Hadley cells and the ocean’s subtropical cells by the trade winds and their associated surface stresses. An anomalous oceanic wind-driven cross-equatorial cell transports energy across the equator, strongly offsetting the imposed heating contrast. The circulation of this cell can be described by the combination of trade wind anomalies and the meridional gradient of sea surface temperature, which sets the temperature contrast between its upper and lower branches. The ability of the wind-driven ocean circulation to damp ITCZ shifts represents a previously unappreciated constraint on the atmosphere’s energy budget and indicates that the position of the ITCZ may be much less sensitive to interhemispheric heating contrasts than previously thought. Climatic implications of this damping are discussed.

APA, Harvard, Vancouver, ISO, and other styles

30

Larson, Sarah M., Ben P. Kirtman, and Daniel J. Vimont. "A Framework to Decompose Wind-Driven Biases in Climate Models Applied to CCSM/CESM in the Eastern Pacific." Journal of Climate 30, no. 21 (November 2017): 8763–82. http://dx.doi.org/10.1175/jcli-d-17-0099.1.

Full text

Abstract:

Annual cycle biases in climate models are suspected to be largely wind driven along the equator, with winds first driving SST changes that then influence the overlying atmospheric circulation. This study utilizes an experimental approach to test the hypothesis that seasonally varying climatological wind stress directly contributes to the SST and ITCZ biases in the eastern equatorial Pacific. Results show that removing the wind stress annual cycle from the ocean forcing, without constraining the atmosphere and ocean dynamics or buoyancy coupling in the NCAR CCSM4/CESM1.2.0 models, results in a remarkable reduction in the SST annual cycle and springtime ITCZ biases. Improvements in the SST occur primarily because wind-driven errors in the variability of horizontal temperature advection are damped. The ITCZ problem is closely tied to biases in the wind-driven near-equatorial SST. Additional model experiments and analyses reveal that the contributions from zonal and meridional wind stress to the biases are locally forced within 10°S–10°N and additive, suggesting that the biases are driven by independent processes. The zonal and meridional components drive different aspects of the SST annual cycle bias and contribute to the springtime ITCZ bias in different zonal locations. Both the atmosphere and ocean components of the model, separately, are shown to produce unfavorable ocean surface conditions for the simulation of a realistic springtime ITCZ, deeming this a coupled problem. Results show that wind stress may act as a pathway for process-based errors in climate models to directly drive SST and ITCZ biases.

APA, Harvard, Vancouver, ISO, and other styles

31

Stanley, Geoff J., and Oleg A. Saenko. "Bottom-Enhanced Diapycnal Mixing Driven by Mesoscale Eddies: Sensitivity to Wind Energy Supply." Journal of Physical Oceanography 44, no. 1 (January 1, 2014): 68–85. http://dx.doi.org/10.1175/jpo-d-13-0116.1.

Full text

Abstract:

Abstract It has been estimated that much of the wind energy input to the ocean general circulation is removed by mesoscale eddies via baroclinic instability. While the fate of this energy remains a subject of research, arguments have been presented suggesting that a fraction of it may get transferred to lee waves that, upon breaking, result in bottom-enhanced diapycnal mixing. Here the authors propose several parameterizations of this process and explore their impact in a low-resolution ocean–climate model, focusing on their impact on the abyssal meridional overturning circulation (MOC) of Antarctic Bottom Water. This study shows that, when the eddy energy is allowed to maintain diapycnal mixing, the abyssal MOC generally intensifies with increasing wind energy input to the ocean. In such a case, the whole system is driven by the wind: wind steepens isopycnals and generates eddies, and the (parameterized) eddies generate small-scale mixing, driving the MOC. It is also demonstrated that if the model diapycnal diffusivity, eddy transfer coefficient, and surface climate are decoupled from the winds, then stronger wind stress in the Southern Ocean may lead to a weaker MOC in the abyss—in line with previous results. A simple scaling theory, describing the response of the abyssal MOC strength to wind energy input, is developed, providing a better insight on the numerical results.

APA, Harvard, Vancouver, ISO, and other styles

32

Ikeda, M. "Feedback Mechanism Among Decadal Oscillations in Northern Hemisphere Atmospheric Circulation, Sea Ice, and Ocean Circulation." Annals of Glaciology 14 (1990): 120–23. http://dx.doi.org/10.3189/s0260305500008399.

Full text

Abstract:

Decadal oscillations of the ice cover in the Barents Sea are examined for the period since 1950. They are highly correlated with atmospheric circulation when that circulation has an anomalous low pressure over the Barents Sea and Eurasian Basin, while the ice cover is weakly correlated with local air temperature. A feedback mechanism between Barents Sea ice and the atmospheric circulation is suggested; increased cyclonic wind-stress curl reduces cold Arctic flow to the Barents Sea and reduces the sea ice. The reduced ice cover encourages heat flux from the Barents Sea to the atmosphere, tending to reinforce the low pressure. This positive feedback amplifies the oscillations of the air–ice–ocean system driven by external forcing with relatively weak decadal variability. A two-level ocean model, which is driven by prescribed buoyancy flux and wind stresses, confirms that Arctic outflow to the Barents Sea decreases during a cyclonic wind stress.

APA, Harvard, Vancouver, ISO, and other styles

33

Ikeda, M. "Feedback Mechanism Among Decadal Oscillations in Northern Hemisphere Atmospheric Circulation, Sea Ice, and Ocean Circulation." Annals of Glaciology 14 (1990): 120–23. http://dx.doi.org/10.1017/s0260305500008399.

Full text

Abstract:

Decadal oscillations of the ice cover in the Barents Sea are examined for the period since 1950. They are highly correlated with atmospheric circulation when that circulation has an anomalous low pressure over the Barents Sea and Eurasian Basin, while the ice cover is weakly correlated with local air temperature. A feedback mechanism between Barents Sea ice and the atmospheric circulation is suggested; increased cyclonic wind-stress curl reduces cold Arctic flow to the Barents Sea and reduces the sea ice. The reduced ice cover encourages heat flux from the Barents Sea to the atmosphere, tending to reinforce the low pressure. This positive feedback amplifies the oscillations of the air–ice–ocean system driven by external forcing with relatively weak decadal variability. A two-level ocean model, which is driven by prescribed buoyancy flux and wind stresses, confirms that Arctic outflow to the Barents Sea decreases during a cyclonic wind stress.

APA, Harvard, Vancouver, ISO, and other styles

34

Sheremet, V. A., G. R. Ierley, and V. M. Kamenkovich. "Eigenanalysis of the two-dimensional wind-driven ocean circulation problem." Journal of Marine Research 55, no. 1 (January 1, 1997): 57–92. http://dx.doi.org/10.1357/0022240973224463.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Ghil, M., Y. Feliks, and L. U. Sushama. "Baroclinic and barotropic aspects of the wind-driven ocean circulation." Physica D: Nonlinear Phenomena 167, no. 1-2 (July 2002): 1–35. http://dx.doi.org/10.1016/s0167-2789(02)00392-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Linhao, Zhong, Feng Shide, and Gao Shouting. "Wind-driven ocean circulation in shallow water lattice Boltzmann model." Advances in Atmospheric Sciences 22, no. 3 (June 2005): 349–58. http://dx.doi.org/10.1007/bf02918749.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Hogg, Andrew Mc C., Peter D. Killworth, Jeffrey R. Blundell, and William K. Dewar. "Mechanisms of Decadal Variability of the Wind-Driven Ocean Circulation." Journal of Physical Oceanography 35, no. 4 (April 1, 2005): 512–31. http://dx.doi.org/10.1175/jpo2687.1.

Full text

Abstract:

Abstract Eddy-resolving quasigeostrophic simulations of wind-driven circulation in a large ocean basin are presented. The results show that strong modes of low-frequency variability arise in many parameter regimes and that the strength of these modes depends upon the presence of inertial recirculations in the flow field. The inertial recirculations arise through advection of anomalous potential vorticity by the western boundary current and are barotropized by the effect of baroclinic eddies in the flow. The mechanism of low-frequency oscillations is explored with reference to previous studies, and it is found that the observed mode can be linked to the gyre mode but is strongly modified by the effect of eddies.

APA, Harvard, Vancouver, ISO, and other styles

38

Abramov, Rafail V., and Andrew J. Majda. "Low-Frequency Climate Response of Quasigeostrophic Wind-Driven Ocean Circulation." Journal of Physical Oceanography 42, no. 2 (February 1, 2012): 243–60. http://dx.doi.org/10.1175/jpo-d-11-052.1.

Full text

Abstract:

Abstract Linear response to external perturbation through the fluctuation–dissipation theorem has recently become a popular topic in the climate research community. It relates an external perturbation of climate dynamics to climate change in a simple linear fashion, which provides key insight into physics of the climate change phenomenon. Recently, the authors developed a suite of linear response algorithms for low-frequency response of large-scale climate dynamics to external perturbation, including the novel blended response algorithm, which combines the geometrically exact general response formula using integration of a linear tangent model at short response times and the classical quasi-Gaussian response algorithm at longer response times, overcoming numerical instability of the tangent linear model for longer times due to positive Lyapunov exponents. Here, the authors apply the linear response framework to several leading empirical orthogonal functions (EOFs) of a quasigeostrophic model of wind-driven ocean circulation. It is demonstrated that the actual nonlinear response of this system under external perturbation at leading EOFs can be predicted by the linear response algorithms with adequate skill with moderate errors; in particular, the blended response algorithm has a pattern correlation with the ideal response operator on the four leading EOFs of the mean state response of 94% after 5 yr. In addition, interesting properties of the mean flow response to large-scale changes in wind stress at the leading EOFs are observed.

APA, Harvard, Vancouver, ISO, and other styles

39

De Szoeke, R. A. "On the Wind-Driven Circulation of the South Pacific Ocean." Journal of Physical Oceanography 17, no. 5 (May 1987): 613–30. http://dx.doi.org/10.1175/1520-0485(1987)017<0613:otwdco>2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Mcwilliams, James C., Nancy J. Norton, Peter R. Gent, and Dale B. Haidvogel. "A Linear Balance Model of Wind-Driven, Midlatitude Ocean Circulation." Journal of Physical Oceanography 20, no. 9 (September 1990): 1349–78. http://dx.doi.org/10.1175/1520-0485(1990)020<1349:albmow>2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Gjermundsen, Ada, Joseph H. LaCasce, and Liv Denstad. "The Thermally Driven Ocean Circulation with Realistic Bathymetry." Journal of Physical Oceanography 48, no. 3 (March 2018): 647–65. http://dx.doi.org/10.1175/jpo-d-17-0147.1.

Full text

Abstract:

AbstractThe global circulation driven solely by relaxation to an idealized surface temperature profile and to interior mixing is examined. Forcing by winds and evaporation/precipitation is excluded. The resulting circulation resembles the observed in many ways, and the overturning is of similar magnitude. The overturning is driven by large-scale upwelling in the interior (which is relatively large, because of the use of a constant mixing coefficient). The compensating downwelling occurs in the northern North Atlantic and in the Ross and Weddell Seas, with an additional, smaller contribution from the northern North Pacific. The latter is weaker because the Bering Strait limits the northward extent of the flow. The downwelling occurs in frictional layers near the boundaries and depends on the lateral shear in the horizontal flow. The shear, in turn, is linked to the imposed surface temperature gradient via thermal wind, and as such, the downwelling can be reduced or eliminated in selected regions by removing the surface gradient. Doing so in the northern North Atlantic causes the (thermally driven) Antarctic Circumpolar Current to intensify, increasing the sinking along Antarctica. Eliminating the surface gradient in the Southern Ocean increases the sinking in the North Atlantic and Pacific. As there is upwelling also in the western boundary currents, the flow must increase even more to accomplish the necessary downwelling. The implications of the results are then considered, particularly with respect to Arctic intensification of global warming, which will reduce the surface temperature gradient.

APA, Harvard, Vancouver, ISO, and other styles

42

SHAJI, C., A. D. RAO, S. K. DUBE, and N. BAHULAYAN. "On the semi-diagnostic computation of climatological circulation in the western tropical Indian Ocean." MAUSAM 51, no. 4 (December 17, 2021): 329–48. http://dx.doi.org/10.54302/mausam.v51i4.1790.

Full text

Abstract:

The seasonal mean climatological circulation in the Indian Ocean north of 20°S and west of 80°E during the summer and winter has been investigated using a 3-dimensional, fully non-linear, semi-diagnostic circulation model. The model equations include the basic ocean hydrothermodynamic equations of momentum, hydrostatics, continuity, sea surface topography and temperature and salt transport equations. Model is driven with the seasonal mean data on wind stress at the ocean surface and thermohaline forcing at different levels. The circulation in the upper levels of the ocean at 20, 50, 150, 300, 500 and 1000 m depths during the two contrasting seasons has been obtained using the model, and the role of steady, local forcing of wind and internal density field on the dynamical balance of circulation in the western tropical Indian Ocean is explained. The climatological temperature and salinity data used to drive the model is found to be hydrodynamically adjusted with surface wind, flow field and bottom relief during the adaptation stages. Semi-diagnostic technique is found to be very effective for the smoothening of climatic temperature and salinity data and also to obtain the 3-dimensional steady state circulation, which would serve as initial condition in simulation models of circulation.

APA, Harvard, Vancouver, ISO, and other styles

43

Nikurashin, Maxim, and Geoffrey Vallis. "A Theory of Deep Stratification and Overturning Circulation in the Ocean." Journal of Physical Oceanography 41, no. 3 (March 1, 2011): 485–502. http://dx.doi.org/10.1175/2010jpo4529.1.

Full text

Abstract:

Abstract A simple theoretical model of the deep stratification and meridional overturning circulation in an idealized single-basin ocean with a circumpolar channel is presented. The theory includes the effects of wind, eddies, and diapycnal mixing; predicts the deep stratification in terms of the surface forcing and other problem parameters; makes no assumption of zero residual circulation; and consistently accounts for the interaction between the circumpolar channel and the rest of the ocean. The theory shows that dynamics of the overturning circulation can be characterized by two limiting regimes, corresponding to weak and strong diapycnal mixing. The transition between the two regimes is described by a nondimensional number characterizing the strength of the diffusion-driven compared to the wind-driven overturning circulation. In the limit of weak diapycnal mixing, deep stratification throughout the ocean is produced by the effects of wind and eddies in a circumpolar channel and maintained even in the limit of vanishing diapycnal diffusivity and in a flat-bottomed ocean. The overturning circulation across the deep stratification is driven by the diapycnal mixing in the basin away from the channel but is sensitive, through changes in stratification, to the wind and eddies in the channel. In the limit of strong diapycnal mixing, deep stratification is primarily set by eddies in the channel and diapycnal mixing in the basin away from the channel, with the wind over the circumpolar channel playing a secondary role. Analytical solutions for the deep stratification and overturning circulation in the limit of weak diapycnal mixing and numerical solutions that span the regimes of weak to strong diapycnal mixing are presented. The theory is tested with a coarse-resolution ocean general circulation model configured in an idealized geometry. A series of experiments performed to examine the sensitivity of the deep stratification and the overturning circulation to variations in wind stress and diapycnal mixing compare well with predictions from the theory.

APA, Harvard, Vancouver, ISO, and other styles

44

Hogg, Andrew McC, Paul Spence, Oleg A. Saenko, and Stephanie M. Downes. "The Energetics of Southern Ocean Upwelling." Journal of Physical Oceanography 47, no. 1 (January 2017): 135–53. http://dx.doi.org/10.1175/jpo-d-16-0176.1.

Full text

Abstract:

AbstractThe ocean’s meridional overturning circulation is closed by the upwelling of dense, carbon-rich waters to the surface of the Southern Ocean. It has been proposed that upwelling in this region is driven by strong westerly winds, implying that the intensification of Southern Ocean winds in recent decades may have enhanced the rate of upwelling, potentially affecting the global overturning circulation. However, there is no consensus on the sensitivity of upwelling to winds or on the nature of the connection between Southern Ocean processes and the global overturning circulation. In this study, the sensitivity of the overturning circulation to changes in Southern Ocean westerly wind stress is investigated using an eddy-permitting ocean–sea ice model. In addition to a suite of standard circulation metrics, an energy analysis is used to aid dynamical interpretation of the model response. Increased Southern Ocean wind stress enhances the upper cell of the overturning circulation through creation of available potential energy in the Southern Hemisphere, associated with stronger upwelling of deep water. Poleward shifts in the Southern Ocean westerlies lead to a complicated transient response, with the formation of bottom water induced by increased polynya activity in the Weddell Sea and a weakening of the upper overturning cell in the Northern Hemisphere. The energetic consequences of the upper overturning cell response indicate an interhemispheric connection to the input of available potential energy in the Northern Hemisphere.

APA, Harvard, Vancouver, ISO, and other styles

45

Klinger, Barry A., and Carlos Cruz. "Decadal Response of Global Circulation to Southern Ocean Zonal Wind Stress Perturbation." Journal of Physical Oceanography 39, no. 8 (August 1, 2009): 1888–904. http://dx.doi.org/10.1175/2009jpo4070.1.

Full text

Abstract:

Abstract A substantial component of North Atlantic Deep Water formation may be driven by westerly wind stress over the Southern Ocean. Variability of this wind stress on decadal time scales may lead to circulation variability far from the forcing region. The Hybrid Coordinate Ocean Model (HYCOM), a numerical ocean model, is used to investigate the spatial patterns and the time scales associated with such wind variability. The evolution of circulation and density anomalies is observed by comparing one 80-yr simulation, forced in part by relatively strong Southern Hemisphere westerlies, with a simulation driven by climatological wind. The volume transport anomaly takes about 10 yr to reach near-full strength in the entire Southern Hemisphere; however, in the Northern Hemisphere, it grows for the duration of the run. The Southern Hemisphere Indo-Pacific volume transport anomaly is about twice the strength of that found in the Atlantic. In the thermocline, water exits the southern westerlies belt in a broad flow that feeds a western boundary current (WBC) in both the Atlantic and Pacific Oceans. These WBCs in turn feed an Indonesian Throughflow from the Pacific and cyclonic gyres in the far north, which are broadly consistent with the Stommel–Arons theory. The deep return flow in each hemisphere is strongly affected by deep-sea ridges, which leads to a number of midocean “WBCs.” The wind perturbation causes isopycnals to sink over most of the basin. After about 20 yr, this sinking is very roughly uniform with latitude, though it varies by basin.

APA, Harvard, Vancouver, ISO, and other styles

46

Spence, Paul, Erik van Sebille, Oleg A. Saenko, and Matthew H. England. "Using Eulerian and Lagrangian Approaches to Investigate Wind-Driven Changes in the Southern Ocean Abyssal Circulation." Journal of Physical Oceanography 44, no. 2 (February 1, 2013): 662–75. http://dx.doi.org/10.1175/jpo-d-13-0108.1.

Full text

Abstract:

Abstract This study uses a global ocean eddy-permitting climate model to explore the export of abyssal water from the Southern Ocean and its sensitivity to projected twenty-first-century poleward-intensifying Southern Ocean wind stress. The abyssal flow pathways and transport are investigated using a combination of Lagrangian and Eulerian techniques. In an Eulerian format, the equator- and poleward flows within similar abyssal density classes are increased by the wind stress changes, making it difficult to explicitly diagnose changes in the abyssal export in a meridional overturning circulation framework. Lagrangian particle analyses are used to identify the major export pathways of Southern Ocean abyssal waters and reveal an increase in the number of particles exported to the subtropics from source regions around Antarctica in response to the wind forcing. Both the Lagrangian particle and Eulerian analyses identify transients as playing a key role in the abyssal export of water from the Southern Ocean. Wind-driven modifications to the potential energy component of the vorticity balance in the abyss are also found to impact the Southern Ocean barotropic circulation.

APA, Harvard, Vancouver, ISO, and other styles

47

Krebs, Uta, and A. Timmermann. "Tropical Air–Sea Interactions Accelerate the Recovery of the Atlantic Meridional Overturning Circulation after a Major Shutdown." Journal of Climate 20, no. 19 (October 1, 2007): 4940–56. http://dx.doi.org/10.1175/jcli4296.1.

Full text

Abstract:

Abstract Using a coupled ocean–sea ice–atmosphere model of intermediate complexity, the authors study the influence of air–sea interactions on the stability of the Atlantic Meridional Overturning Circulation (AMOC). Mimicking glacial Heinrich events, a complete shutdown of the AMOC is triggered by the delivery of anomalous freshwater forcing to the northern North Atlantic. Analysis of fully and partially coupled freshwater perturbation experiments under glacial conditions shows that associated changes of the heat transport in the North Atlantic lead to a cooling north of the thermal equator and an associated strengthening of the northeasterly trade winds. Because of advection of cold air and an intensification of the trade winds, the intertropical convergence zone (ITCZ) is shifted southward. Changes of the accumulated precipitation lead to the generation of a positive salinity anomaly in the northern tropical Atlantic and a negative anomaly in the southern tropical Atlantic. During the shutdown phase of the AMOC, cross-equatorial oceanic surface flow is halted, preventing dilution of the positive salinity anomaly in the North Atlantic. Advected northward by the wind-driven ocean circulation, the positive salinity anomaly increases the upper-ocean density in the deep-water formation regions, thereby accelerating the recovery of the AMOC considerably. Partially coupled experiments that neglect tropical air–sea coupling reveal that the recovery time of the AMOC is almost twice as long as in the fully coupled case. The impact of a shutdown of the AMOC on the Indian and Pacific Oceans can be decomposed into atmospheric and oceanic contributions. Temperature anomalies in the Northern Hemisphere are largely controlled by atmospheric circulation anomalies, whereas those in the Southern Hemisphere are strongly determined by ocean dynamical changes and exhibit a time lag of several decades. An intensification of the Pacific meridional overturning cell in the northern North Pacific during the AMOC shutdown can be explained in terms of wind-driven ocean circulation changes acting in concert with global ocean adjustment processes.

APA, Harvard, Vancouver, ISO, and other styles

48

Thompson, Luanne. "The Effect of Continental Rises on the Wind-Driven Ocean Circulation." Journal of Physical Oceanography 25, no. 6 (June 1995): 1296–316. http://dx.doi.org/10.1175/1520-0485(1995)025<1296:teocro>2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

RIBBE, JOACHIM. "On wind-driven mid-latitude convection in ocean general circulation models." Tellus A 51, no. 4 (September 19, 2002): 517–25. http://dx.doi.org/10.1034/j.1600-0870.1999.t01-4-00005.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Woodberry, Karen E., Mark E. Luther, and James J. O'Brien. "The wind-driven seasonal circulation in the southern tropical Indian Ocean." Journal of Geophysical Research 94, no. C12 (1989): 17985. http://dx.doi.org/10.1029/jc094ic12p17985.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Wind driven ocean circulation'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles