Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018
We investigated the long-term changes of the principal tidal component M 2 along North Atlantic coasts, from 1846 to 2018. We analysed 18 tide gauges with time series starting no later than 1940. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to re...
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ftcopernicus:oai:publications.copernicus.org:os85989 2023-05-15T17:28:14+02:00 Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018 Pineau-Guillou, Lucia Lazure, Pascal Wöppelmann, Guy 2021-01-04 application/pdf https://doi.org/10.5194/os-17-17-2021 https://os.copernicus.org/articles/17/17/2021/ eng eng doi:10.5194/os-17-17-2021 https://os.copernicus.org/articles/17/17/2021/ eISSN: 1812-0792 Text 2021 ftcopernicus https://doi.org/10.5194/os-17-17-2021 2021-01-11T17:22:15Z We investigated the long-term changes of the principal tidal component M 2 along North Atlantic coasts, from 1846 to 2018. We analysed 18 tide gauges with time series starting no later than 1940. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to remove the 18.6-year nodal modulation. We found that M 2 variations are consistent at all the stations in the North-East Atlantic (Cuxhaven, Delfzijl, Hoek van Holland, Newlyn, Brest), whereas some discrepancies appear in the North-West Atlantic. The changes started long before the 20th century and are not linear. The secular trends in M 2 amplitude vary from one station to another; most of them are positive, up to 2.5 mm/yr at Wilmington since 1910. Since 1990, the trends switch from positive to negative values in the North-East Atlantic. Concerning the possible causes of the observed changes, the similarity between the North Atlantic Oscillation and M 2 variations in the North-East Atlantic suggests a possible influence of the large-scale atmospheric circulation on the tide. Our statistical analysis confirms large correlations at all the stations in the North-East Atlantic. We discuss a possible underlying mechanism. A different spatial distribution of mean sea level (corresponding to water depth) from one year to another, depending on the low-frequency sea-level pressure patterns, could impact the propagation of the tide in the North Atlantic basin. However, the hypothesis is at present unproven. Text North Atlantic North Atlantic oscillation North East Atlantic North West Atlantic Copernicus Publications: E-Journals Hoek ENVELOPE(-65.050,-65.050,-66.000,-66.000) Ocean Science 17 1 17 34 |
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Open Polar |
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Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
We investigated the long-term changes of the principal tidal component M 2 along North Atlantic coasts, from 1846 to 2018. We analysed 18 tide gauges with time series starting no later than 1940. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to remove the 18.6-year nodal modulation. We found that M 2 variations are consistent at all the stations in the North-East Atlantic (Cuxhaven, Delfzijl, Hoek van Holland, Newlyn, Brest), whereas some discrepancies appear in the North-West Atlantic. The changes started long before the 20th century and are not linear. The secular trends in M 2 amplitude vary from one station to another; most of them are positive, up to 2.5 mm/yr at Wilmington since 1910. Since 1990, the trends switch from positive to negative values in the North-East Atlantic. Concerning the possible causes of the observed changes, the similarity between the North Atlantic Oscillation and M 2 variations in the North-East Atlantic suggests a possible influence of the large-scale atmospheric circulation on the tide. Our statistical analysis confirms large correlations at all the stations in the North-East Atlantic. We discuss a possible underlying mechanism. A different spatial distribution of mean sea level (corresponding to water depth) from one year to another, depending on the low-frequency sea-level pressure patterns, could impact the propagation of the tide in the North Atlantic basin. However, the hypothesis is at present unproven. |
format |
Text |
author |
Pineau-Guillou, Lucia Lazure, Pascal Wöppelmann, Guy |
spellingShingle |
Pineau-Guillou, Lucia Lazure, Pascal Wöppelmann, Guy Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018 |
author_facet |
Pineau-Guillou, Lucia Lazure, Pascal Wöppelmann, Guy |
author_sort |
Pineau-Guillou, Lucia |
title |
Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018 |
title_short |
Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018 |
title_full |
Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018 |
title_fullStr |
Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018 |
title_full_unstemmed |
Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018 |
title_sort |
large-scale changes of the semidiurnal tide along north atlantic coasts from 1846 to 2018 |
publishDate |
2021 |
url |
https://doi.org/10.5194/os-17-17-2021 https://os.copernicus.org/articles/17/17/2021/ |
long_lat |
ENVELOPE(-65.050,-65.050,-66.000,-66.000) |
geographic |
Hoek |
geographic_facet |
Hoek |
genre |
North Atlantic North Atlantic oscillation North East Atlantic North West Atlantic |
genre_facet |
North Atlantic North Atlantic oscillation North East Atlantic North West Atlantic |
op_source |
eISSN: 1812-0792 |
op_relation |
doi:10.5194/os-17-17-2021 https://os.copernicus.org/articles/17/17/2021/ |
op_doi |
https://doi.org/10.5194/os-17-17-2021 |
container_title |
Ocean Science |
container_volume |
17 |
container_issue |
1 |
container_start_page |
17 |
op_container_end_page |
34 |
_version_ |
1766120787895386112 |