Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean
The aim of the present study is to develop an efficient assimilation scheme suitable for assimilating satellite altimeter data into a basin-scale eddy-resolving primitive equation model with active thermodynamics. Two alternative methods, referred to as extended nudging and re-initialization, respec...
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ftoceanrep:oai:oceanrep.geomar.de:5543 2023-05-15T17:31:42+02:00 Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean Oschlies, Andreas 1994 text https://oceanrep.geomar.de/id/eprint/5543/ https://oceanrep.geomar.de/id/eprint/5543/1/IFM-BER_256.pdf https://oceanrep.geomar.de/id/eprint/5543/7/Diss.%201994%20Oschlies,%20A.pdf https://doi.org/10.3289/ifm_ber_256 en eng https://oceanrep.geomar.de/id/eprint/5543/1/IFM-BER_256.pdf https://oceanrep.geomar.de/id/eprint/5543/7/Diss.%201994%20Oschlies,%20A.pdf Oschlies, A. (1994) Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean. Open Access (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, 129 pp. . Berichte aus dem Institut für Meereskunde an der Christian-Albrechts-Universität Kiel, 256 . DOI 10.3289/ifm_ber_256 <https://doi.org/10.3289/ifm_ber_256>. doi:10.3289/ifm_ber_256 cc_by_3.0 info:eu-repo/semantics/openAccess Thesis NonPeerReviewed 1994 ftoceanrep https://doi.org/10.3289/ifm_ber_256 2023-04-07T14:51:12Z The aim of the present study is to develop an efficient assimilation scheme suitable for assimilating satellite altimeter data into a basin-scale eddy-resolving primitive equation model with active thermodynamics. Two alternative methods, referred to as extended nudging and re-initialization, respectively, will be presented and intercompared. The first approach essentially extrapolates the surface observations into the ocean interior using a priori correlations provided by the model climatology. In contrast, the second assimilation procedure emphasizes dynamical relationships and in particular the conservation of temperature and salinity on isopycnals, rather than relying heavily on uncertain statistical correlations. Both methods are tested and found to perform about equally well by running identical twin experiments, in which the model is assumed perfect and generates its own data for assimilation. Twin experiments are further used to compare the assimilation of the altimeter data directly along the satellite ground tracks with the assimilation of preprocessed maps combining all the data within some chosen time window. The results of these experiments indicate that - as far as the assimilation techniques proposed in this study are concerned - assimilation of quasi-synoptic maps is preferential. The actual assimilation experiments are performed with objectively analyzed sea surface height anomalies measured by the U.S. Navy's satellite GEOSAT. Adding the model's mean sea surface to obtain an estimate of absolute dynamic sea level, these maps are then assimilated into the WOCE (World Ocean Circulation Experiment) CME (Community Modelling Effort) model of the North Atlantic Ocean at 5-day intervals covering the year 1987. While the results of the two alternative assimilation procedures were almost indistinguishable in the identical twin experiments using simulated data, marked differences emerge when real altimeter data are used. These differences are shown to arise from different physical and statistical ... Thesis North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
The aim of the present study is to develop an efficient assimilation scheme suitable for assimilating satellite altimeter data into a basin-scale eddy-resolving primitive equation model with active thermodynamics. Two alternative methods, referred to as extended nudging and re-initialization, respectively, will be presented and intercompared. The first approach essentially extrapolates the surface observations into the ocean interior using a priori correlations provided by the model climatology. In contrast, the second assimilation procedure emphasizes dynamical relationships and in particular the conservation of temperature and salinity on isopycnals, rather than relying heavily on uncertain statistical correlations. Both methods are tested and found to perform about equally well by running identical twin experiments, in which the model is assumed perfect and generates its own data for assimilation. Twin experiments are further used to compare the assimilation of the altimeter data directly along the satellite ground tracks with the assimilation of preprocessed maps combining all the data within some chosen time window. The results of these experiments indicate that - as far as the assimilation techniques proposed in this study are concerned - assimilation of quasi-synoptic maps is preferential. The actual assimilation experiments are performed with objectively analyzed sea surface height anomalies measured by the U.S. Navy's satellite GEOSAT. Adding the model's mean sea surface to obtain an estimate of absolute dynamic sea level, these maps are then assimilated into the WOCE (World Ocean Circulation Experiment) CME (Community Modelling Effort) model of the North Atlantic Ocean at 5-day intervals covering the year 1987. While the results of the two alternative assimilation procedures were almost indistinguishable in the identical twin experiments using simulated data, marked differences emerge when real altimeter data are used. These differences are shown to arise from different physical and statistical ... |
format |
Thesis |
author |
Oschlies, Andreas |
spellingShingle |
Oschlies, Andreas Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean |
author_facet |
Oschlies, Andreas |
author_sort |
Oschlies, Andreas |
title |
Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean |
title_short |
Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean |
title_full |
Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean |
title_fullStr |
Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean |
title_full_unstemmed |
Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean |
title_sort |
assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the north atlantic ocean |
publishDate |
1994 |
url |
https://oceanrep.geomar.de/id/eprint/5543/ https://oceanrep.geomar.de/id/eprint/5543/1/IFM-BER_256.pdf https://oceanrep.geomar.de/id/eprint/5543/7/Diss.%201994%20Oschlies,%20A.pdf https://doi.org/10.3289/ifm_ber_256 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/5543/1/IFM-BER_256.pdf https://oceanrep.geomar.de/id/eprint/5543/7/Diss.%201994%20Oschlies,%20A.pdf Oschlies, A. (1994) Assimilation of satellite altimeter data into an eddy-reolving primitive equation model of the North Atlantic Ocean. Open Access (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, 129 pp. . Berichte aus dem Institut für Meereskunde an der Christian-Albrechts-Universität Kiel, 256 . DOI 10.3289/ifm_ber_256 <https://doi.org/10.3289/ifm_ber_256>. doi:10.3289/ifm_ber_256 |
op_rights |
cc_by_3.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.3289/ifm_ber_256 |
_version_ |
1766129395497435136 |