A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution
A unified method of approximation, extrapolation, and objective layering is offered for processing vertical oceanographic profiles. The method is demonstrated using seawater density and consists of adjustable splitting of each individual profile into N vertical layers based on tentative, piecewise l...
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Journal of Oceanography
2008
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ftipnmexicoir:oai:www.repositoriodigital.ipn.mx:123456789/13576 2023-07-16T04:00:43+02:00 A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution Makarov, Viatcheslav Georgievich Zaitsev, Oleg Budaeva, Valentina D. Salinas González, Felipe 2008-01-01 http://www.repositoriodigital.ipn.mx/handle/123456789/13576 en eng Journal of Oceanography 0916-8370 http://www.repositoriodigital.ipn.mx/handle/123456789/13576 Splitting Into Layers Sea of Okhotsk Vertical Extrapolation Piecewise Curve-Fitting Density Profile Homogeneous Approximation Nonlinear Least Squares Method Article 2008 ftipnmexicoir 2023-06-28T10:39:49Z A unified method of approximation, extrapolation, and objective layering is offered for processing vertical oceanographic profiles. The method is demonstrated using seawater density and consists of adjustable splitting of each individual profile into N vertical layers based on tentative, piecewise linear homogeneous approximation with specified accuracy and a final fitting of an N-layered analytical model to data. A set of 3N coefficients of the model includes one density value at the sea surface; N–1 depths of layer interfaces; and N pairs of coefficients that describe a profile shape within the n-th layer—an asymptotic density value (a key parameter for extrapolation) and a vertical scale of maximum density variability (related to vertical gradient). Several distinctive characteristics of the technique are: (1) It can be used for the analysis of the vertical structure of individual profiles when N is an unknown parameter, and spatial interpolation when N should be equal for all profiles. (2) A justified downward extrapolation of incomplete data is possible with the model, especially if historical deepwater profiles are available. (3) Layer interfaces, as well as other coefficients, are derived with only one fitting to the ntire profile. (4) The technique, using its general formulation, can serve as a parent for developing various types of models. The simpler step-like (with hyperbolic or exponential approximation) and more complicated smooth (continuous in gradient space) models were designed and tested against a large number of density profiles from the Sea of Okhotsk and the Gulf of California. Comparison of parametric, z-levels and isopycnal averaging was done for the region off the northeastern coast of Sakhalin. Instituto Politécnico Nacional (IPN). Centro Interdisciplinario de Ciencias Marinas Ciencias Marinas PDF Article in Journal/Newspaper Sakhalin El Instituto Politécnico Nacional (IPN): Repositorio Digital Institucional (RDI) Okhotsk |
institution |
Open Polar |
collection |
El Instituto Politécnico Nacional (IPN): Repositorio Digital Institucional (RDI) |
op_collection_id |
ftipnmexicoir |
language |
English |
topic |
Splitting Into Layers Sea of Okhotsk Vertical Extrapolation Piecewise Curve-Fitting Density Profile Homogeneous Approximation Nonlinear Least Squares Method |
spellingShingle |
Splitting Into Layers Sea of Okhotsk Vertical Extrapolation Piecewise Curve-Fitting Density Profile Homogeneous Approximation Nonlinear Least Squares Method Makarov, Viatcheslav Georgievich Zaitsev, Oleg Budaeva, Valentina D. Salinas González, Felipe A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution |
topic_facet |
Splitting Into Layers Sea of Okhotsk Vertical Extrapolation Piecewise Curve-Fitting Density Profile Homogeneous Approximation Nonlinear Least Squares Method |
description |
A unified method of approximation, extrapolation, and objective layering is offered for processing vertical oceanographic profiles. The method is demonstrated using seawater density and consists of adjustable splitting of each individual profile into N vertical layers based on tentative, piecewise linear homogeneous approximation with specified accuracy and a final fitting of an N-layered analytical model to data. A set of 3N coefficients of the model includes one density value at the sea surface; N–1 depths of layer interfaces; and N pairs of coefficients that describe a profile shape within the n-th layer—an asymptotic density value (a key parameter for extrapolation) and a vertical scale of maximum density variability (related to vertical gradient). Several distinctive characteristics of the technique are: (1) It can be used for the analysis of the vertical structure of individual profiles when N is an unknown parameter, and spatial interpolation when N should be equal for all profiles. (2) A justified downward extrapolation of incomplete data is possible with the model, especially if historical deepwater profiles are available. (3) Layer interfaces, as well as other coefficients, are derived with only one fitting to the ntire profile. (4) The technique, using its general formulation, can serve as a parent for developing various types of models. The simpler step-like (with hyperbolic or exponential approximation) and more complicated smooth (continuous in gradient space) models were designed and tested against a large number of density profiles from the Sea of Okhotsk and the Gulf of California. Comparison of parametric, z-levels and isopycnal averaging was done for the region off the northeastern coast of Sakhalin. Instituto Politécnico Nacional (IPN). Centro Interdisciplinario de Ciencias Marinas Ciencias Marinas PDF |
format |
Article in Journal/Newspaper |
author |
Makarov, Viatcheslav Georgievich Zaitsev, Oleg Budaeva, Valentina D. Salinas González, Felipe |
author_facet |
Makarov, Viatcheslav Georgievich Zaitsev, Oleg Budaeva, Valentina D. Salinas González, Felipe |
author_sort |
Makarov, Viatcheslav Georgievich |
title |
A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution |
title_short |
A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution |
title_full |
A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution |
title_fullStr |
A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution |
title_full_unstemmed |
A Piecewise Curve-Fitting Technique for Vertical Oceanographic Profiles and its Application to Density Distribution |
title_sort |
piecewise curve-fitting technique for vertical oceanographic profiles and its application to density distribution |
publisher |
Journal of Oceanography |
publishDate |
2008 |
url |
http://www.repositoriodigital.ipn.mx/handle/123456789/13576 |
geographic |
Okhotsk |
geographic_facet |
Okhotsk |
genre |
Sakhalin |
genre_facet |
Sakhalin |
op_relation |
0916-8370 http://www.repositoriodigital.ipn.mx/handle/123456789/13576 |
_version_ |
1771549797606490112 |