Operational Modeling: Semienclosed Basin Modeling at the Naval Oceanographic Office

Horton,; Clifford,; Cole,; Schmitz,; Kantha,

doi:10.5670/oceanog.1992.36

Cited by 17 publications

(4 citation statements)

References 1 publication

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“…The curvilinear version of the model (CUPOM), developed and documented by Kantha and Piacsek (1997), differs from the original POM by an improved mixed layer parametrisation (Kantha and Clayson 1994). The model yields a realistic description of the locations of 20 fronts, seasonal variability and depth and location of deep convection (Horton et al 1992, Horton et al 1997, Lopez and Kantha 2000, Clayson et al 2008. The σ -z version of CUPOM used in this study follows the structure of the σ -version.…”

Section: Numerical Modelmentioning

confidence: 97%

Effects of mesoscale eddies in the active mixed layer: test of the parametrisation in eddy resolving simulations

Luneva

Clayson

Dubovikov

2015

Geophysical & Astrophysical Fluid Dynamics

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In eddy resolving simulations, we test a mixed layer mesoscale parametrisation, developed recently by Canuto and Dubovikov [Ocean Model., 2011, 39, 200-207]. With no adjustable parameters, the parametrisation yields the horizontal and vertical mesoscale fluxes in terms of coarse-resolution fields 10 and eddy kinetic energy (EKE). We compare terms of the parametrisation diagnosed from coarsegrained fields with the eddy mesoscale fluxes diagnosed directly from the high resolution model. An expression for the EKE in terms of mean fields has also been found to get a closed parametrisation in terms of the mean fields only. In 40 numerical experiments we simulated two types of flows: idealised flows driven by baroclinic instabilities only, and more realistic flows, driven by wind and 15 surface fluxes as well as by inflow-outflow. The diagnosed quasi-instantaneous horizontal and vertical mesoscale buoyancy fluxes (averaged over 1 • -2 • and 10 days) demonstrate a strong scatter typical for turbulent flows, however, the fluxes are positively correlated with the parametrisation with higher (0.5 − 0.74) correlations at the experiments with larger baroclinic radius Rossby. After being averaged over 3-4 months, diffusivities diagnosed from the eddy resolving simulations are consistent with the 20 parametrisation for a broad range of parameters. Diagnosed vertical mesoscale fluxes restratify mixed layer and are in a good agreement with the parametrisation unless vertical turbulent mixing in the upper layer becomes strong enough in comparison with mesoscale advection. In the latter case, numerical simulations demonstrate that the deviation of the fluxes from the parametrisation is controlled by dimensionless parameter estimating the ratio of vertical turbulent mixing term to mesoscale advection. 25An analysis using a modified ω-equation reveals that the effects of the vertical mixing of vorticity is responsible for the two-three fold amplification of vertical mesoscale flux. Possible physical mechanisms, responsible for the amplification of vertical mesoscale flux are discussed.

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Section: Numerical Modelmentioning

confidence: 97%

Effects of mesoscale eddies in the active mixed layer: test of the parametrisation in eddy resolving simulations

Luneva

Clayson

Dubovikov

2015

Geophysical & Astrophysical Fluid Dynamics

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“…Circulation and water mass formation in the Persian Gulf have been the subject of several previous modeling studies (Lardner et al 1987(Lardner et al , 1988(Lardner et al , 1989(Lardner et al , 1993Lardner and Das 1991;Chao et al 1992;Horton et al 1992;Song et al 1994;Blain 2000;Azam et al 2006;Elshorbagy et al 2006;Kämpf and Sadrinasab 2006). Several of these studies used either hydrodynamic numerical models or spectral models of coarse to moderate horizontal resolutions (20-5 km) and were driven by density only or monthly atmospheric forcings.…”

Section: Introductionmentioning

confidence: 98%

A Modeling Study of Circulation and Eddies in the Persian Gulf

Thoppil

Hogan

2010

Journal of Physical Oceanography

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The circulation and mesoscale eddies in the Persian Gulf are investigated using results from a highresolution (;1 km) Hybrid Coordinate Ocean Model (HYCOM). The circulation in the Persian Gulf is composed of two spatial scales: basin scale and mesoscale. The progression of a cyclonic circulation cell dominates the basin-scale circulation in the eastern half of the gulf (528-558E) during March-July. This is primarily the consequence of density-driven outflow-inflow through the Strait of Hormuz and strong stratification. A northwestward-flowing Iranian Coastal Current (ICC; 30-40 cm s 21 ) between the Strait of Hormuz and north of Qatar (;528E) forms the northern flank of the cell. Between July and August the ICC becomes unstable because of the baroclinic instability mechanism by releasing the potential energy stored in the cross-shelf density gradient. As a result, the meanders in the ICC evolve into a series of mesoscale eddies, which is denoted as the Iranian coastal eddies (ICE). The ICE have a diameter of about 115-130 km and extend vertically over most of the water column. Three cyclonic eddies produced by the model during August-September 2005 compared quite well with the Moderate Resolution Imaging Spectroradiometer (MODIS) SST and chlorophyll-a observations. The remnants of ICE are seen until November, after which they dissipate as the winter cooling causes the thermocline to collapse.

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“…The model was successfully applied at CU to nowcast/forecasts in the Gulf of Mexico (Choi et al, 1995;Kantha, 1999), the tropical Pacific (Clayson, 1995), the North Indian Ocean (Lopez, 1998;Lopez and Kantha, 2000), the North Pacific (Engelhardt, 1996) and the Sea of Japan (Suk and Kantha, 1997). The operational versions of the model are used at the Naval Oceanographic Office (NAVO) for the Mediterranean Sea (Horton et al, 1997), the Red Sea (Clifford et al, 1997), the Baltic Sea and the Persian Gulf (Horton et al, 1991(Horton et al, , 1992. The σ-z version of CUPOM used in this study follows the structure of the sigma version.…”

Section: Numerical Codementioning

confidence: 99%

Mixed layer mesoscales: a parameterization for OGCMs

Canuto

Dubovikov

Luneva

et al. 2010

Preprint

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We derive and assess a parameterization of the mixed layer vertical and horizontal mesoscale fluxes of an arbitrary tracer. The results, which are obtained by solving the mesoscale dynamic equations and contain no adjustable parameters, are expressed in terms of the large scale fields resolved by coarse resolution OGCMs (ocean global circulation models). The new model can be put in the right perspective by considering the following. Thus far, the lack of a mixed layer mesoscale model that naturally satisfies the required boundary condition (the vertical flux must vanish at the surface), was remedied by extending the stream function modeled for the adiabatic deep ocean into the mixed layer using an arbitrary tapering function chosen to enforce the required boundary condition. The present model renders the tapering schemes unnecessary for the vertical flux automatically vanishes at the ocean surface. The expressions we derive for the vertical and horizontal mesoscale fluxes are algebraic and should be used in conjunction with any of the available mesoscale models valid in the adiabatic deep ocean. We also discuss a new feature representing the effect of sub-mesoscales on mesoscales. It is shown that in the case of strong wind, one must add to the mean Eulerian velocity that enters the parameterization of the mesoscale fluxes a new term due to sub-mesoscales whose explicit form we work out. The assessment of the model results is as follows. First, previous eddy resolving results indicated a robust re-stratification effect by mesoscales; we show that the model result for the mesoscale vertical flux leads to re-stratification (its second z-derivative is negative) and that it is of the same order of magnitude but opposite sign of the vertical flux by small scale turbulence, leading to a large cancellation. Second, since mesoscales act as a source of the eddy kinetic energy, we compare the predicted surface values vs. the Topex-Poseidon. Third, we carry out an eddy resolving simulation and assess both z-profile and magnitude of the model vertical flux against the simulation data. The tests yield positive results. A more stratified mixed layer has implication for the oceanic absorption of heat and CO2, a feature whose implications on climate predictions we hope to explore in the future

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Operational Modeling: Semienclosed Basin Modeling at the Naval Oceanographic Office

Cited by 17 publications

References 1 publication

Effects of mesoscale eddies in the active mixed layer: test of the parametrisation in eddy resolving simulations

Effects of mesoscale eddies in the active mixed layer: test of the parametrisation in eddy resolving simulations

A Modeling Study of Circulation and Eddies in the Persian Gulf

Mixed layer mesoscales: a parameterization for OGCMs

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