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Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient

In preparing gravity gradient reference maps for navigation purposes, researchers have tended to use a constant value for the density of seawater. However, the actual seawater density at a particular location may vary due to the effects of longitude, latitude and bathymetry. In this study, the right...

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Autores principales: Xian, Pengfei, Ji, Bing, Bian, Shaofeng, Zong, Jingwen, Zhang, Tao
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9865657/
https://www.ncbi.nlm.nih.gov/pubmed/36679510
http://dx.doi.org/10.3390/s23020714
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author Xian, Pengfei
Ji, Bing
Bian, Shaofeng
Zong, Jingwen
Zhang, Tao
author_facet Xian, Pengfei
Ji, Bing
Bian, Shaofeng
Zong, Jingwen
Zhang, Tao
author_sort Xian, Pengfei
collection PubMed
description In preparing gravity gradient reference maps for navigation purposes, researchers have tended to use a constant value for the density of seawater. However, the actual seawater density at a particular location may vary due to the effects of longitude, latitude and bathymetry. In this study, the right rectangular prism method was used to calculate the disturbing gravity gradient caused by the mass deficiency of seawater for three different seawater profiles in an area east of Taiwan. For this purpose, two seawater density models were used as alternatives to the constant seawater density model, and the alteration in the gravity gradient was calculated to quantify the error in the gravity gradient as a result of using a constant seawater density. The results demonstrated that the error in the gravity gradient can reach 1E for water at large depths. Moreover, the difference between the amplitude of the error of the corrected thermocline and that for the uncorrected seawater density model was found to be quite small. If a gravity gradient reference map with accuracy better than 1E is to be realized, the seawater density cannot be taken as constant during forward modeling.
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spelling pubmed-98656572023-01-22 Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient Xian, Pengfei Ji, Bing Bian, Shaofeng Zong, Jingwen Zhang, Tao Sensors (Basel) Article In preparing gravity gradient reference maps for navigation purposes, researchers have tended to use a constant value for the density of seawater. However, the actual seawater density at a particular location may vary due to the effects of longitude, latitude and bathymetry. In this study, the right rectangular prism method was used to calculate the disturbing gravity gradient caused by the mass deficiency of seawater for three different seawater profiles in an area east of Taiwan. For this purpose, two seawater density models were used as alternatives to the constant seawater density model, and the alteration in the gravity gradient was calculated to quantify the error in the gravity gradient as a result of using a constant seawater density. The results demonstrated that the error in the gravity gradient can reach 1E for water at large depths. Moreover, the difference between the amplitude of the error of the corrected thermocline and that for the uncorrected seawater density model was found to be quite small. If a gravity gradient reference map with accuracy better than 1E is to be realized, the seawater density cannot be taken as constant during forward modeling. MDPI 2023-01-08 /pmc/articles/PMC9865657/ /pubmed/36679510 http://dx.doi.org/10.3390/s23020714 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Xian, Pengfei
Ji, Bing
Bian, Shaofeng
Zong, Jingwen
Zhang, Tao
Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient
title Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient
title_full Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient
title_fullStr Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient
title_full_unstemmed Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient
title_short Influence of Differences in the Density of Seawater on the Measurement of the Underwater Gravity Gradient
title_sort influence of differences in the density of seawater on the measurement of the underwater gravity gradient
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9865657/
https://www.ncbi.nlm.nih.gov/pubmed/36679510
http://dx.doi.org/10.3390/s23020714
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