Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay
International audience The characterization of model errors is an essential step for effective data assimilation into open-ocean and shelf-seas models. In this paper, we propose an experimental protocol to properly estimate the error statistics generated by imperfect atmospheric forcings in a region...
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ftunigrenoble:oai:HAL:hal-00230125v1 2024-05-12T08:08:10+00:00 Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay Broquet, Grégoire Brasseur, Pierre Rozier, David Brankart, Jean-Michel Verron, Jacques Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS) 2007-11-21 https://hal.science/hal-00230125 https://doi.org/10.1007/s10236-007-0128-z en eng HAL CCSD Springer Verlag info:eu-repo/semantics/altIdentifier/doi/10.1007/s10236-007-0128-z hal-00230125 https://hal.science/hal-00230125 doi:10.1007/s10236-007-0128-z http://creativecommons.org/licenses/by/ ISSN: 1616-7341 EISSN: 1616-7228 Ocean Dynamics https://hal.science/hal-00230125 Ocean Dynamics, 2007, ⟨10.1007/s10236-007-0128-z⟩ Regional data assimilation Model error Atmospheric forcings Bay of Biscay Representers [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] info:eu-repo/semantics/article Journal articles 2007 ftunigrenoble https://doi.org/10.1007/s10236-007-0128-z 2024-04-18T03:41:48Z International audience The characterization of model errors is an essential step for effective data assimilation into open-ocean and shelf-seas models. In this paper, we propose an experimental protocol to properly estimate the error statistics generated by imperfect atmospheric forcings in a regional model of the Bay of Biscay, nested in a basin-scale North Atlantic configuration. The model used is the Hybrid Coordinate Ocean Model (HYCOM), and the experimental protocol involves Monte Carlo (or ensemble) simulations. The spatial structure of the model error is analyzed using the representer technique, which allows us to anticipate the subsequent impact in data assimilation systems. The results show that the error is essentially anisotropic and inhomogeneous, affecting mainly the model layers close to the surface. Even when the forcings errors are centered around zero, a divergence is observed between the central forecast and the mean forecast of the Monte Carlo simulations as a result of nonlinearities. The 3D structure of the representers characterizes the capacity of different types of measurement (sea level, sea surface temperature, surface velocities, subsurface temperature, and salinity) to control the circulation. Finally, data assimilation experiments demonstrate the superiority of the proposed methodology for the implementation of reduced-order Kalman filters. Article in Journal/Newspaper North Atlantic Université Grenoble Alpes: HAL Ocean Dynamics 58 1 1 17 |
institution |
Open Polar |
collection |
Université Grenoble Alpes: HAL |
op_collection_id |
ftunigrenoble |
language |
English |
topic |
Regional data assimilation Model error Atmospheric forcings Bay of Biscay Representers [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] |
spellingShingle |
Regional data assimilation Model error Atmospheric forcings Bay of Biscay Representers [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] Broquet, Grégoire Brasseur, Pierre Rozier, David Brankart, Jean-Michel Verron, Jacques Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay |
topic_facet |
Regional data assimilation Model error Atmospheric forcings Bay of Biscay Representers [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] |
description |
International audience The characterization of model errors is an essential step for effective data assimilation into open-ocean and shelf-seas models. In this paper, we propose an experimental protocol to properly estimate the error statistics generated by imperfect atmospheric forcings in a regional model of the Bay of Biscay, nested in a basin-scale North Atlantic configuration. The model used is the Hybrid Coordinate Ocean Model (HYCOM), and the experimental protocol involves Monte Carlo (or ensemble) simulations. The spatial structure of the model error is analyzed using the representer technique, which allows us to anticipate the subsequent impact in data assimilation systems. The results show that the error is essentially anisotropic and inhomogeneous, affecting mainly the model layers close to the surface. Even when the forcings errors are centered around zero, a divergence is observed between the central forecast and the mean forecast of the Monte Carlo simulations as a result of nonlinearities. The 3D structure of the representers characterizes the capacity of different types of measurement (sea level, sea surface temperature, surface velocities, subsurface temperature, and salinity) to control the circulation. Finally, data assimilation experiments demonstrate the superiority of the proposed methodology for the implementation of reduced-order Kalman filters. |
author2 |
Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Broquet, Grégoire Brasseur, Pierre Rozier, David Brankart, Jean-Michel Verron, Jacques |
author_facet |
Broquet, Grégoire Brasseur, Pierre Rozier, David Brankart, Jean-Michel Verron, Jacques |
author_sort |
Broquet, Grégoire |
title |
Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay |
title_short |
Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay |
title_full |
Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay |
title_fullStr |
Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay |
title_full_unstemmed |
Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay |
title_sort |
estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the bay of biscay |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00230125 https://doi.org/10.1007/s10236-007-0128-z |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 1616-7341 EISSN: 1616-7228 Ocean Dynamics https://hal.science/hal-00230125 Ocean Dynamics, 2007, ⟨10.1007/s10236-007-0128-z⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1007/s10236-007-0128-z hal-00230125 https://hal.science/hal-00230125 doi:10.1007/s10236-007-0128-z |
op_rights |
http://creativecommons.org/licenses/by/ |
op_doi |
https://doi.org/10.1007/s10236-007-0128-z |
container_title |
Ocean Dynamics |
container_volume |
58 |
container_issue |
1 |
container_start_page |
1 |
op_container_end_page |
17 |
_version_ |
1798851079667974144 |