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Abstract(s)
A configuração dos fundos e da linha de costa em Portugal Continental influenciam a propagação da onda de maré junto à costa. Os registos maregráficos,
obtidos nas estações da Rede Maregráfica Nacional, permitiram caracterizar o tipo
de maré e efetuar a análise e previsão da maré astronómica nos principais portos
nacionais. Na costa de Portugal, a maré é do tipo semidiurno regular, o que permite
deduzir certas relações entre a amplitude e o retardo, das principais constituintes
semidiurnas, pelo método não-harmónico. No presente trabalho, apresentam-se comparações e concordâncias entre marégrafos próximos, para diferentes áreas e portos
principais, para ser possível ter uma perceção de como se propaga a maré ao longo
da costa. Para isso foi utilizado o software R e folhas de cálculo Excel para calcular as concordâncias dos portos. Foram também analisadas possíveis alterações das
relações entre portos ao longo do tempo. O objetivo principal do presente trabalho
foi cumprido tendo sido obtidos numerosos dados e gráficos com boa qualidade e
passíveis de uma boa análise crítica onde se pode perceber como se propaga a maré
na costa ocidental portuguesa. Destacam-se vários aspetos inovadores neste trabalho, nomeadamente as concordâncias entre portos principais que é algo que não foi
encontrado em mais nenhum trabalho ou estudo, e o facto de ter sido analisado
um longo período de dados permitindo não só perceber como evoluiu a propagação
da maré e as suas constituintes ao longo dos anos, mas como se propaga agora no
presente e quais são as diferenças que daí advêm. Entre várias conclusões retiradas
com este trabalho as mais significativas foram: o marégrafo de Aveiro não é favorável
para concordâncias entre portos principais, a onda de maré propaga-se de Sul para
Norte na costa ocidental portuguesa demorando 26′ 15′′, entre Sines e Leixões, com
velocidade de, aproximadamente, 821 km/h.
The configuration of the seabed and the coastline in mainland Portugal influence the tidal wave propagation near the coast. The tide gauge records, obtained in the stations of the National Tide Gauge Network, allowed to characterize the type of tide and to perform the analysis and forecast of the astronomical tide in the main national ports. In the Portuguese coast, the tide is of the regular semidiurnal type, which allows deducing certain relations between the amplitude and the delay, of the main semidiurnal constituents, by the non-harmonic method. In the present work, comparisons and concordances are presented between nearby tide gauges, for different areas and main ports, in order to be able to have a perception of how the tide propagates along the coast. This was done using the software R and Excel spreadsheets to calculate port concordances. Possible changes in the relationships between ports over time were also analysed. The main objective of the present work was fulfilled having been obtained numerous data and graphs with good quality and susceptible of a good critical analysis where it is possible to understand how the tide propagates in the Portuguese western coast. We highlight several innovative aspects in this work, namely the concordances between main ports which is something that has not been found in any other work or study, and the fact that a long period of data has been analysed allowing not only to understand how the tidal propagation and its constituents evolved over the years, but how it propagates now in the present and what are the differences arising from it. Among several conclusions drawn with this work the most significant were: the tide gauge of Aveiro is not favourable for concordances between main ports, the tidal wave propagates from south to north on the Portuguese west coast, taking 26′ 15′′, between Sines and Leixões, with a speed of approximately 821 km/h.
The configuration of the seabed and the coastline in mainland Portugal influence the tidal wave propagation near the coast. The tide gauge records, obtained in the stations of the National Tide Gauge Network, allowed to characterize the type of tide and to perform the analysis and forecast of the astronomical tide in the main national ports. In the Portuguese coast, the tide is of the regular semidiurnal type, which allows deducing certain relations between the amplitude and the delay, of the main semidiurnal constituents, by the non-harmonic method. In the present work, comparisons and concordances are presented between nearby tide gauges, for different areas and main ports, in order to be able to have a perception of how the tide propagates along the coast. This was done using the software R and Excel spreadsheets to calculate port concordances. Possible changes in the relationships between ports over time were also analysed. The main objective of the present work was fulfilled having been obtained numerous data and graphs with good quality and susceptible of a good critical analysis where it is possible to understand how the tide propagates in the Portuguese western coast. We highlight several innovative aspects in this work, namely the concordances between main ports which is something that has not been found in any other work or study, and the fact that a long period of data has been analysed allowing not only to understand how the tidal propagation and its constituents evolved over the years, but how it propagates now in the present and what are the differences arising from it. Among several conclusions drawn with this work the most significant were: the tide gauge of Aveiro is not favourable for concordances between main ports, the tidal wave propagates from south to north on the Portuguese west coast, taking 26′ 15′′, between Sines and Leixões, with a speed of approximately 821 km/h.
Description
Keywords
Concordâncias de maré Constituintes harmónicas Constituintes não harmónicas Dados maregráficos Maré