Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter
The objective of the DIADEM and TOPAZ projects is the development of a pre-operational forecasting prototype for the North Atlantic Ocean, based on advanced assimilation methods. During DIADEM, a demonstration experiment has already been set up, assimilating satellite data into the Miami isopycnic c...
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ftccsdartic:oai:HAL:hal-00230238v1 2023-05-15T17:31:17+02:00 Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter Birol, Florence Brankart, Jean-Michel Brasseur, Pierre Verron, Jacques Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI) Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF) Nice, France 2003 https://hal.archives-ouvertes.fr/hal-00230238 en eng HAL CCSD hal-00230238 https://hal.archives-ouvertes.fr/hal-00230238 http://creativecommons.org/licenses/by/ EGS Conference https://hal.archives-ouvertes.fr/hal-00230238 EGS Conference, 2003, Nice, France [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/conferenceObject Conference papers 2003 ftccsdartic 2021-10-24T21:29:14Z The objective of the DIADEM and TOPAZ projects is the development of a pre-operational forecasting prototype for the North Atlantic Ocean, based on advanced assimilation methods. During DIADEM, a demonstration experiment has already been set up, assimilating satellite data into the Miami isopycnic coordinate ocean (MICOM) model. The new system (TOPAZ) is based on the hybrid coordinate, primitive equation ocean model HYCOM developed at RSMAS, on a 1/3º horizontal grid. The vertical discretization is isopycnal in the ocean interior and z-levels in the mixed layer and shallow-water regions. This new coordinate system improves the discretization of the physical variables and a larger part of the observed signal can then be taken into account by the assimilation process. The assimilation scheme is the SEEK filter (Singular Evolutive Extended Kalman Filter), a reduced order approximation of the Kalman filter, in which only the most significant directions of forecast error are controlled by the observations. The SEEK assimilation scheme has been upgrated to also incorporate hydrographic in situ measurements in addition to surface observations. In theory this only requires a new observation operator and three-dimensional, multivariate error covariances. However a keypoint is the choice of a new estimation space ensuring the robustness of the method. In this contribution, we analyse preliminary results obtained with the upgrated system. The attention will be focused on the statistical behavior of the filter and the impact of different surface data sets in the assimilation process. Conference Object North Atlantic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[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 |
[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] Birol, Florence Brankart, Jean-Michel Brasseur, Pierre Verron, Jacques Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter |
topic_facet |
[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 |
The objective of the DIADEM and TOPAZ projects is the development of a pre-operational forecasting prototype for the North Atlantic Ocean, based on advanced assimilation methods. During DIADEM, a demonstration experiment has already been set up, assimilating satellite data into the Miami isopycnic coordinate ocean (MICOM) model. The new system (TOPAZ) is based on the hybrid coordinate, primitive equation ocean model HYCOM developed at RSMAS, on a 1/3º horizontal grid. The vertical discretization is isopycnal in the ocean interior and z-levels in the mixed layer and shallow-water regions. This new coordinate system improves the discretization of the physical variables and a larger part of the observed signal can then be taken into account by the assimilation process. The assimilation scheme is the SEEK filter (Singular Evolutive Extended Kalman Filter), a reduced order approximation of the Kalman filter, in which only the most significant directions of forecast error are controlled by the observations. The SEEK assimilation scheme has been upgrated to also incorporate hydrographic in situ measurements in addition to surface observations. In theory this only requires a new observation operator and three-dimensional, multivariate error covariances. However a keypoint is the choice of a new estimation space ensuring the robustness of the method. In this contribution, we analyse preliminary results obtained with the upgrated system. The attention will be focused on the statistical behavior of the filter and the impact of different surface data sets in the assimilation process. |
author2 |
Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI) Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF) |
format |
Conference Object |
author |
Birol, Florence Brankart, Jean-Michel Brasseur, Pierre Verron, Jacques |
author_facet |
Birol, Florence Brankart, Jean-Michel Brasseur, Pierre Verron, Jacques |
author_sort |
Birol, Florence |
title |
Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter |
title_short |
Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter |
title_full |
Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter |
title_fullStr |
Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter |
title_full_unstemmed |
Multivariate assimilation into layered ocean models of the North Atlantic using the SEEK filter |
title_sort |
multivariate assimilation into layered ocean models of the north atlantic using the seek filter |
publisher |
HAL CCSD |
publishDate |
2003 |
url |
https://hal.archives-ouvertes.fr/hal-00230238 |
op_coverage |
Nice, France |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
EGS Conference https://hal.archives-ouvertes.fr/hal-00230238 EGS Conference, 2003, Nice, France |
op_relation |
hal-00230238 https://hal.archives-ouvertes.fr/hal-00230238 |
op_rights |
http://creativecommons.org/licenses/by/ |
_version_ |
1766128785735811072 |