Toward a stochastic parameterization of ocean mesoscale eddies

Mana, PierGianLuca Porta; Zanna, Laure

doi:10.1016/j.ocemod.2014.04.002

Cited by 118 publications

(122 citation statements)

References 96 publications

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“…Let us consider the problem of the optimal ship route in the form of Equation (27) and formulate the algorithms for its numerical solution. Suppose that X(t) is a solution to the minimization problem posed.…”

Section: Algorithms For Solving the Problem Of The Optimal Ship Routementioning

confidence: 99%

“…The first one is the classical established basis, viz., a subsystem describing the dynamics of rotating fluid in the framework of approximations traditional in oceanology [2,25]. The second one includes physical parameterizations of various kinds, which change as we gain a better understanding of natural phenomena [25][26][27]. On this basis we use the splitting method by physical processes as a methodology for constructing a model and develop efficient numerical methods for solving it.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Modeling of Marine Circulation, Pollution Assessment and Optimal Ship Routes

Zalesny

Agoshkov

Aps

et al. 2017

JMSE

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Methods and technology have been developed to solve a wide range of problems in the dynamics of sea currents and to assess their "impact" on objects in the marine environment. Technology can be used for monitoring and forecasting sea currents, for solving the problems of minimizing risks and analyzing marine disasters associated with the choice of the optimal course of the ship, and assessing the pollution of coastal zones, etc. The technology includes a numerical model of marine circulation with improved resolution of coastal zones, a method for solving the inverse problem of contamination of the sea with a passive impurity, and a variational algorithm for constructing the optimal trajectory of the vessel. The methods and technology are illustrated by solving problems of Baltic Sea dynamics. The model of sea dynamics is governed by primitive equations that are solved on a grid with an improved resolution of the selected coastal zone-in this case, the Gulf of Finland. The equations of the model are formulated in a bipolar orthogonal coordinate system with an arbitrary arrangement of poles and the sigma coordinate in the vertical direction. An increase in the horizontal resolution of the allocated zone is achieved due to the displacement of the north pole in the vicinity of the city of St. Petersburg. A class of dangerous technogenic situations and natural phenomena (sea accidents, which can be investigated with the help of the proposed methodology), includes tanker accidents in the case of a possible collision with a stationary object (with "dynamic danger") or a moving object (including another ship), accidents on oil-producing platforms and oil pipelines, and coastal pollution.

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Section: Algorithms For Solving the Problem Of The Optimal Ship Routementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Marine Circulation, Pollution Assessment and Optimal Ship Routes

Zalesny

Agoshkov

Aps

et al. 2017

JMSE

View full text Add to dashboard Cite

show abstract

“…[6,29,41]. While such a horizontal coarsegraining set-up preserves some of the properties induced by the vertical strati cation, a clear de nition of the associated mesoscale eddy forcing is di cult both numerically and physically.…”

Section: Introduction Background and Motivationmentioning

confidence: 99%

“…While such a horizontal coarsegraining set-up preserves some of the properties induced by the vertical strati cation, a clear de nition of the associated mesoscale eddy forcing is di cult both numerically and physically. Numerically, one is faced with nontrivial ltering options [41,48] that subtly change the de nition of the eddy forcing. In turn, physical interpretations of such eddy forcings are non-transparent to a certain extent because horizontally coarsegrained terms mix partly resolved processes of both barotropic and baroclinic nature.…”

Section: Introduction Background and Motivationmentioning

confidence: 99%

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Covariate-based stochastic parameterization of baroclinic ocean eddies

Verheul¹,

Viebahn²,

Crommelin³

2017

Mathematics of Climate and Weather Forecasting

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Abstract:In this study we investigate a covariate-based stochastic approach to parameterize unresolved turbulent processes within a standard model of the idealised, wind-driven ocean circulation. We focus on vertical instead of horizontal coarse-graining, such that we avoid the subtle di culties of horizontal coarsegraining. The corresponding eddy forcing is uniquely de ned and has a clear physical interpretation related to baroclinic instability. We propose to emulate the baroclinic eddy forcing by sampling from the conditional probability distribution functions of the eddy forcing obtained from the baroclinic reference model data. These conditional probability distribution functions are approximated here by sampling uniformly from discrete reference values. We analyze in detail the di erent performances of the stochastic parameterization dependent on whether the eddy forcing is conditioned on a suitable ow-dependent covariate or on a timelagged covariate or on both. The results demonstrate that our non-Gaussian, non-linear methodology is able to accurately reproduce the rst four statistical moments and spatial/temporal correlations of the stream function, energetics, and enstrophy of the reference baroclinic model.

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Stochastic modeling of decadal variability in ocean gyres

Kondrashov

Berloff

2015

Geophysical Research Letters

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Decadal large-scale low-frequency variability of the ocean circulation due to its nonlinear dynamics remains a big challenge for theoretical understanding and practical ocean modeling. This paper presents a novel fully data driven approach that addresses this challenge. Proposed is non-Markovian low-order methodology with stochastic closure and use of mode decomposition by multichannel Singular Spectrum Analysis. The multilayer stochastic linear model is obtained from the coarse-grained eddy-resolving ocean model solution, and with high accuracy it reproduces the main statistical properties of the decadal variability. The proposed methodology does not depend on the governing fluid dynamics equations and geometry of the problem, and it can be extended to other ocean models and ultimately to the real data. BackgroundMidlatitude atmosphere and ocean possess not only significant interannual variability but also several large-scale variability modes on decadal and interdecadal timescales: North Atlantic Oscillation, Atlantic Multidecadal Oscillation, and Pacific Decadal Oscillation. Oceanic evidence of these modes is found in the sea surface temperature [Hansen and Bezdek, 1996], hydrography [Qiu and Joyce, 1992], and altimetry [Qiu and Chen, 2005], and it is mostly expressed in structural changes of the eastward jet extensions and the adjacent recirculation zones of the main western boundary currents, such as the Gulf Stream and Kuroshio. Physical origins of these large-scale low-frequency variability (LFV) modes remain unclear, and it is not even known to what extent these origins are intrinsic atmospheric, intrinsic oceanic, or coupled oceanic-atmospheric. One of the reasons, why coupled ocean-atmosphere comprehensive general circulation models (GCMs) cannot distinguish between these scenarios, is inability of their oceanic model components to simulate mesoscale eddies and their impact on the large-scale currents accurately and for a long time. On the other hand, seasonally forced, eddy-resolving ocean-only GCMs exhibit significant intrinsic LFV variability of mesoscale activity [Penduff et al., 2011], intergyre heat transport [Hall et al., 2004], sea level height [Cabanes et al., 2006], western boundary currents [Taguchi et al., 2007], and meridional overturning circulation [Biastoch et al., 2008]. This suggests that not only significant part of the LFV is intrinsic to the ocean but also oceanic mesoscale eddies could play significant role in driving it.Present theoretical understanding of the intrinsic LFV of the ocean starts from the null hypothesis that the ocean integrates high-frequency atmospheric forcing and responds in terms of the red variability spectrum [Hasselman, 1976]. However, over the last 20 years it became evident that in the presence of stochastic, seasonal, or constant atmospheric forcing, the most significant intrinsic LFV of the ocean is not red but operates on interannual-to-interdecadal time scales. One idea is that this variability can be understood in terms of early bifurcations...

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Toward a stochastic parameterization of ocean mesoscale eddies

Cited by 118 publications

References 96 publications

Numerical Modeling of Marine Circulation, Pollution Assessment and Optimal Ship Routes

Numerical Modeling of Marine Circulation, Pollution Assessment and Optimal Ship Routes

Covariate-based stochastic parameterization of baroclinic ocean eddies

Stochastic modeling of decadal variability in ocean gyres

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