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| Resseguier, Valentin; Memin, E.; Chapron, Bertrand. |
| A stochastic flow representation is considered with the Eulerian velocity decomposed between a smooth large scale component and a rough small-scale turbulent component. The latter is specified as a random field uncorrelated in time. Subsequently, the material derivative is modified and leads to a stochastic version of the material derivative to include a drift correction, an inhomogeneous and anisotropic diffusion, and a multiplicative noise. As derived, this stochastic transport exhibits a remarkable energy conservation property for any realizations. As demonstrated, this pivotal operator further provides elegant means to derive stochastic formulations of classical representations of geophysical flow dynamics. |
| Tipo: Text |
Palavras-chave: Stochastic flows; Uncertainty quantification; Ensemble forecasts; Upper ocean dynamics. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00385/49598/51086.pdf |
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| Resseguier, Valentin; Memin, E.; Chapron, Bertrand. |
| Models under location uncertainty are derived assuming that a component of the velocity is uncorrelated in time. The material derivative is accordingly modified to include an advection correction, inhomogeneous and anisotropic diffusion terms and a multiplicative noise contribution. In this paper, simplified geophysical dynamics are derived from a Boussinesq model under location uncertainty. Invoking usual scaling approximations and a moderate influence of the subgrid terms, stochastic formulations are obtained for the stratified Quasi-Geostrophy and the Surface Quasi-Geostrophy models. Based on numerical simulations, benefits of the proposed stochastic formalism are demonstrated. A single realization of models under location uncertainty can restore... |
| Tipo: Text |
Palavras-chave: Stochastic sub-grid parameterization; Uncertainty quantification; Ensemble forecasts. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00385/49599/51087.pdf |
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