The North Atlantic circulation derived from inverse models

This thesis describes two inverse models solving for a quasi-stationary ocean circulation, and discusses the circulation in the North Atlantic as derived from them. Both models are based on the adjoint technique and use finite-element discretization to accurately represent the sloping bottom topogra...

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Bibliographic Details
Main Author: Sidorenko Dmitry, Stefan
Other Authors: Olbers, Dirk, Schröter, Jens, Schlitzer, Reiner
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: Universität Bremen 2005
Subjects:
80
Online Access:https://media.suub.uni-bremen.de/handle/elib/2090
https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000012023
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spelling ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/2090 2023-05-15T16:18:08+02:00 The North Atlantic circulation derived from inverse models Bestimmung der Ozeanzirkulation im Nordatlantik mit inversen Modellen Sidorenko Dmitry, Stefan Olbers, Dirk Schröter, Jens Schlitzer, Reiner 2005-02-09 application/pdf https://media.suub.uni-bremen.de/handle/elib/2090 https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000012023 eng eng Universität Bremen FB1 Physik/Elektrotechnik https://media.suub.uni-bremen.de/handle/elib/2090 urn:nbn:de:gbv:46-diss000012023 info:eu-repo/semantics/openAccess Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY) CC-BY FEMSECT FEOM IFOM Finite Elements Inverse Models North Atlantic Circulation 80 ddc:80 Dissertation doctoralThesis 2005 ftsubbremen 2022-11-09T07:09:44Z This thesis describes two inverse models solving for a quasi-stationary ocean circulation, and discusses the circulation in the North Atlantic as derived from them. Both models are based on the adjoint technique and use finite-element discretization to accurately represent the sloping bottom topography. First a finite element inverse section model FEMSECT (Losch et al., 2004) is presented together with results of applying it to Fram Strait. FEMSECT exploits the thermal wind relation to estimate the velocity with respect to some reference level, and seeks for a compromise in the least square sense between the hydrographic and mooring data. Its novel feature is the ability to take into account the bottom triangles. Such inverse models are a standard tool to derive ocean transports from hydrographic measurements. However, they are not able to take into account the continuity constraint. The inverse finite element ocean model (IFEOM) presented afterwards respects the continuity locally and globally and also exploits the flexibility of 3D finite element grids. It is based on a steady-state version of the finite element ocean general circulation model FEOM (Danilovet al., 2004a). A steady state velocity field is determined from the momentum equations by the density field, and the stationary equation for the potential density is accounted for as a soft constraint. The IFEOM solves for density by minimizing the misfit between it and the density data under strong momentum and weak tracer balance constraint. Using an additional deep pressure gradient constraint (below 2000 m) is suggested and shown to be crucial for keeping the integral properties of the diagnosed ocean circulation close to those of the forward run of FEOM.The circulation in the North Atlantic is estimated by assimilating several data sets. The results are encouraging and indicate that IFEOM can be used to assimilate a climatological circulation from high quality hydrographic measurements. Doctoral or Postdoctoral Thesis Fram Strait North Atlantic Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen)
institution Open Polar
collection Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen)
op_collection_id ftsubbremen
language English
topic FEMSECT FEOM IFOM Finite Elements Inverse Models North Atlantic Circulation
80
ddc:80
spellingShingle FEMSECT FEOM IFOM Finite Elements Inverse Models North Atlantic Circulation
80
ddc:80
Sidorenko Dmitry, Stefan
The North Atlantic circulation derived from inverse models
topic_facet FEMSECT FEOM IFOM Finite Elements Inverse Models North Atlantic Circulation
80
ddc:80
description This thesis describes two inverse models solving for a quasi-stationary ocean circulation, and discusses the circulation in the North Atlantic as derived from them. Both models are based on the adjoint technique and use finite-element discretization to accurately represent the sloping bottom topography. First a finite element inverse section model FEMSECT (Losch et al., 2004) is presented together with results of applying it to Fram Strait. FEMSECT exploits the thermal wind relation to estimate the velocity with respect to some reference level, and seeks for a compromise in the least square sense between the hydrographic and mooring data. Its novel feature is the ability to take into account the bottom triangles. Such inverse models are a standard tool to derive ocean transports from hydrographic measurements. However, they are not able to take into account the continuity constraint. The inverse finite element ocean model (IFEOM) presented afterwards respects the continuity locally and globally and also exploits the flexibility of 3D finite element grids. It is based on a steady-state version of the finite element ocean general circulation model FEOM (Danilovet al., 2004a). A steady state velocity field is determined from the momentum equations by the density field, and the stationary equation for the potential density is accounted for as a soft constraint. The IFEOM solves for density by minimizing the misfit between it and the density data under strong momentum and weak tracer balance constraint. Using an additional deep pressure gradient constraint (below 2000 m) is suggested and shown to be crucial for keeping the integral properties of the diagnosed ocean circulation close to those of the forward run of FEOM.The circulation in the North Atlantic is estimated by assimilating several data sets. The results are encouraging and indicate that IFEOM can be used to assimilate a climatological circulation from high quality hydrographic measurements.
author2 Olbers, Dirk
Schröter, Jens
Schlitzer, Reiner
format Doctoral or Postdoctoral Thesis
author Sidorenko Dmitry, Stefan
author_facet Sidorenko Dmitry, Stefan
author_sort Sidorenko Dmitry, Stefan
title The North Atlantic circulation derived from inverse models
title_short The North Atlantic circulation derived from inverse models
title_full The North Atlantic circulation derived from inverse models
title_fullStr The North Atlantic circulation derived from inverse models
title_full_unstemmed The North Atlantic circulation derived from inverse models
title_sort north atlantic circulation derived from inverse models
publisher Universität Bremen
publishDate 2005
url https://media.suub.uni-bremen.de/handle/elib/2090
https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000012023
genre Fram Strait
North Atlantic
genre_facet Fram Strait
North Atlantic
op_relation https://media.suub.uni-bremen.de/handle/elib/2090
urn:nbn:de:gbv:46-diss000012023
op_rights info:eu-repo/semantics/openAccess
Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY)
op_rightsnorm CC-BY
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