A Zonally Averaged Ocean Model for the Thermohaline Circulation. Part I: Model Development and Flow Dynamics

1991 ◽  
Vol 21 (12) ◽  
pp. 1713-1724 ◽  
Author(s):  
Daniel G. Wright ◽  
Thomas F. Stocker
Keyword(s):  
Thermohaline Circulation ◽  
Model Development ◽  
Ocean Model ◽  
Flow Dynamics

Modeling and Assessment of the Produced Water Discharges from Offshore Petroleum Platforms

2007 ◽  
Vol 42 (4) ◽  
pp. 303-310 ◽  
Author(s):  
Zhi Chen ◽  
Lin Zhao ◽  
Kenneth Lee ◽  
Charles Hannath
Keyword(s):  
Random Walk ◽  
Produced Water ◽  
Model Development ◽  
Three Dimensional ◽  
Monitoring Program ◽  
Ecological Monitoring ◽  
Numerical Approach ◽  
Ocean Model ◽  
Scale Model ◽  
Water Stream

Abstract There has been a growing interest in assessing the risks to the marine environment from produced water discharges. This study describes the development of a numerical approach, POM-RW, based on an integration of the Princeton Ocean Model (POM) and a Random Walk (RW) simulation of pollutant transport. Specifically, the POM is employed to simulate local ocean currents. It provides three-dimensional hydrodynamic input to a Random Walk model focused on the dispersion of toxic components within the produced water stream on a regional spatial scale. Model development and field validation of the predicted current field and pollutant concentrations were conducted in conjunction with a water quality and ecological monitoring program for an offshore facility located on the Grand Banks of Canada. Results indicate that the POM-RW approach is useful to address environmental risks associated with the produced water discharges.

On the use of idealised test cases for ocean model development

2021 ◽  
Author(s):  
Julie Deshayes
Keyword(s):  
Boundary Conditions ◽  
General Circulation ◽  
Model Development ◽  
General Circulation Models ◽  
Ocean Model ◽  
Ocean Dynamics ◽  
Test Cases ◽  
Training Tool ◽  
Research Activities ◽  
Historical Progress

<p>When comparing realistic simulations produced by two ocean general circulation models, differences may emerge from alternative choices in boundary conditions and forcings, which alters our capacity to identify the actual differences between the two models (in the equations solved, the discretization schemes employed and/or the parameterizations introduced). The use of idealised test cases (idealized configurations with analytical boundary conditions and forcings, resolving a given set of equations) has proven efficient to reveal numerical bugs, determine advantages and pitfalls of certain numerical choices, and highlight remaining challenges. I propose to review historical progress enabled by the use of idealised test cases, and promote their utilization when assessing ocean dynamics as represented by an ocean model. For the latter, I would illustrate my talk using illustrations from my own research activities using NEMO in various contexts. I also see idealised test cases as a promising training tool for inexperienced ocean modellers, and an efficient solution to enlarge collaboration with experts in adjacent disciplines, such as mathematics, fluid dynamics and computer sciences.</p>

scholarly journals Fates and Travel Times of Denmark Strait Overflow Water in the Irminger Basin*

2013 ◽  
Vol 43 (12) ◽  
pp. 2611-2628 ◽  
Author(s):  
Inga M. Koszalka ◽  
Thomas W. N. Haine ◽  
Marcello G. Magaldi
Keyword(s):  
North Atlantic ◽  
Thermohaline Circulation ◽  
Ocean Model ◽  
Potential Density ◽  
Particle Trajectories ◽  
Dense Water ◽  
The North ◽  
Denmark Strait ◽  
Wide Range ◽  
The Mean

Abstract The Denmark Strait Overflow (DSO) supplies about one-third of the North Atlantic Deep Water and is critical to global thermohaline circulation. Knowledge of the pathways of DSO through the Irminger Basin and its transformation there is still incomplete, however. The authors deploy over 10 000 Lagrangian particles at the Denmark Strait in a high-resolution ocean model to study these issues. First, the particle trajectories show that the mean position and potential density of dense waters cascading over the Denmark Strait sill evolve consistently with hydrographic observations. These sill particles transit the Irminger Basin to the Spill Jet section (65.25°N) in 5–7 days and to the Angmagssalik section (63.5°N) in 2–3 weeks. Second, the dense water pathways on the continental shelf are consistent with observations and particles released on the shelf in the strait constitute a significant fraction of the dense water particles recorded at the Angmagssalik section within 60 days (~25%). Some particles circulate on the shelf for several weeks before they spill off the shelf break and join the overflow from the sill. Third, there are two places where the water density following particle trajectories decreases rapidly due to intense mixing: to the southwest of the sill and southwest of the Kangerdlugssuaq Trough on the continental slope. After transformation in these places, the overflow particles exhibit a wide range of densities.

Flow Dynamics Under Confined and Unconfined Combustion Conditions

2004 ◽  
Author(s):  
S. Archer ◽  
A. K. Gupta
Keyword(s):  
Spatial Distribution ◽  
Gas Turbine ◽  
Recirculation Zone ◽  
Direct Injection ◽  
Model Development ◽  
Flow Dynamics ◽  
Swirl Number ◽  
Iccd Camera ◽  
Outer Flow ◽  
Lean Direct Injection

Three-dimensional (3-D) flowfield data has been obtained using Particle Image Velocimetry (PIV). Information on selected intermediate flame generated species that mark the flame front and heat release rate has been obtained using optical emission spectroscopy (OES). Instantaneous images on the spatial distribution of OH, CH, and C2 species from within the flames have been obtained using an ICCD camera and narrow band interference filters. The instantaneous images are then integrated to obtain time-averaged information. The PIV and OES diagnostics are employed for varying swirl distributions in the burner. The 3-D data also allows one determine the local swirl number of the resulting flow. Flow characteristics of the resulting flowfield, both without and with combustion, have been examined for the effect of co- and counter-swirl under lean direct injection conditions using unconfined and confined combustor geometry. The OES diagnostics provides information on the spatial distribution of desired species as affected by flame confinement and swirl distribution in flames. Experimental results of the effect of swirl and combustion are presented to simulate the flow dynamics of Lean Direct Injection (LDI) configuration gas turbine combustion. The selected configuration is typical because it does not make use a premixing zone and relies totally on the swirl and the injector to accomplish rapid mixing. Specifically, the effect of radial distribution of combustion air and swirl in a burner are examined under non-burning and burning conditions using propane as the fuel. The present study explores single swirler interaction with the use of an experimental double concentric swirl burner that simulates one swirler of a practical gas turbine combustor. Results showed that both swirl and combustion has significant effect on the characteristics of the internal and external recirculation zones. The calculated local swirl number differs significantly form that estimated using geometrical relationship derived from the vane angle only. The effect of combustion for the confined and unconfined geometries has also been found to be different. In the confined geometry combustion decreases the size of the recirculation zone. This is in contrast to that found for the unconfined conditions. Combustion enhances the recirculation zone in the unconfined geometry. Combustion provides greater velocity magnitudes than their counter noncombustion conditions. The counter-swirl combination resulted in smaller and better defined internal recirculation regions. OES results showed that swirl distribution affects the shape of the spatial distribution by spreading the high intensity regions radially outwards with the co-swirl configuration. Confinement increased the intensity and spatial distribution of the investigated species. The results provide the role of swirl, combustion and flame confinement on the mean and turbulence characteristics of flows over a range of swirl and shear conditions between the inner and outer flow of the burner. The results also provide important role on the flow and chemical behavior. This data provides important insights on the flow dynamics in addition to providing data for model validation and model development.

scholarly journals On the effect of sea-ice dynamics on oceanic thermohaline circulation

1995 ◽  
Vol 21 ◽  
pp. 361-368
Author(s):  
W. D. Hibler ◽  
Jinlun Zhang
Keyword(s):  
Sea Ice ◽  
Thermohaline Circulation ◽  
Ocean Model ◽  
Flat Bottom ◽  
Ice Dynamics ◽  
Surface Ocean ◽  
The North ◽  
Air Temperatures ◽  
Sea Ice Dynamics ◽  
Ocean Salinity

An idealized planetary flat-bottom geostrophic ice–ocean model is constructed with boundaries at latitudes 5° and 65° N and longitudes 50° W and 10° E in order to approximate the North Atlantic. The model is driven by fixed zonally averaged wind, surface air temperatures and surface ocean salinity. A dynamic thermodynamic sea-ice model is coupled to the ocean model. Only the thermodynamic insulating effects of the sea ice are considered, and no salt fluxes due to melting and freezing are included. Four equilibrium simulations of about 5000 years each are performed: two with interactive sea ice with and without ice dynamics, and two control simulations with either a fixed or no ice cover.In the two simulations including interactive sea ice, characteristic oscillations in the ice thickness and ocean temperature are found to occur. The oscillations are smaller when sea-ice dynamics are included. The dominant oscillation occurs at about a 5 year period, with the key feature being that the presence of sea ice tends to insulate the ocean and hence allows an oceanic warming. This warming in turn eventually causes a melt-back of the ice and a subsequent cool-down of the ocean. Oscillations at longer periods of about 20 years in the thermohaline circulation are also observed. These longer-period oscillations are particularly pronounced in the northward surface water transport.

scholarly journals Performance of the Adriatic Sea and Coast (AdriSC) climate component – a COAWST V3.3-based coupled atmosphere–ocean modelling suite: atmospheric dataset

2021 ◽  
Vol 14 (6) ◽  
pp. 3995-4017
Author(s):  
Cléa Denamiel ◽  
Petra Pranić ◽  
Damir Ivanković ◽  
Iva Tojčić ◽  
Ivica Vilibić
Keyword(s):  
Climate Models ◽  
Thermohaline Circulation ◽  
Climate Model ◽  
Adriatic Sea ◽  
Eastern Mediterranean ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Evaluation Study ◽  
Ocean Model ◽  
Climate Studies

Abstract. In this evaluation study, the coupled atmosphere–ocean Adriatic Sea and Coast (AdriSC) climate model, which was implemented to carry out 31-year evaluation and climate projection simulations in the Adriatic and northern Ionian seas, is briefly presented. The kilometre-scale AdriSC atmospheric results, derived with the Weather Research and Forecasting (WRF) 3 km model for the 1987–2017 period, are then thoroughly compared to a comprehensive publicly and freely available observational dataset. The evaluation shows that overall, except for the summer surface temperatures, which are systematically underestimated, the AdriSC WRF 3 km model has a far better capacity to reproduce surface climate variables (and particularly the rain) than the WRF regional climate models at 0.11∘ resolution. In addition, several spurious data have been found in both gridded products and in situ measurements, which thus should be used with care in the Adriatic region for climate studies at local and regional scales. Long-term simulations with the AdriSC climate model, which couples the WRF 3 km model with a 1 km ocean model, might thus be a new avenue to substantially improve the reproduction, at the climate scale, of the Adriatic Sea dynamics driving the Eastern Mediterranean thermohaline circulation. As such it may also provide new standards for climate studies of orographically developed coastal regions in general.

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