Tide distortion and attenuation in an Amazonian tidal river

FREITAS, Paulo Tadeu Amorim; SILVEIRA, Odete Fátima Machado da; ASP NETO, Nils Edvin

Artigo

Tide distortion and attenuation in an Amazonian tidal river

The present study seeks to evaluate tidal propagation in the Guamá-Capim river system, in the Amazonian region, considering hydrodynamic and geomorphological aspects. Available data sets on fluvial discharge and water level variations were considered, besides several methods of measuring the tides (...

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Autor principal:	FREITAS, Paulo Tadeu Amorim
Outros Autores:	SILVEIRA, Odete Fátima Machado da, ASP NETO, Nils Edvin
Grau:	Artigo
Idioma:	eng
Publicado em:	2014
Assuntos:	Marés Propagação da maré Estuários Medidores de fluxo Hidrodinâmica Descarga fluvial Rios Amazônia brasileira Vazão das marés Sistema fluvial Guamá-Capim
Acesso em linha:	http://repositorio.ufpa.br/jspui/handle/2011/5907

id	ir-2011-5907
recordtype	dspace
spelling	ir-2011-59072019-05-22T14:51:01Z Tide distortion and attenuation in an Amazonian tidal river FREITAS, Paulo Tadeu Amorim SILVEIRA, Odete Fátima Machado da ASP NETO, Nils Edvin Marés Propagação da maré Estuários Medidores de fluxo Hidrodinâmica Descarga fluvial Rios Amazônia brasileira Vazão das marés Sistema fluvial Guamá-Capim The present study seeks to evaluate tidal propagation in the Guamá-Capim river system, in the Amazonian region, considering hydrodynamic and geomorphological aspects. Available data sets on fluvial discharge and water level variations were considered, besides several methods of measuring the tides (currents, water levels and discharges) recorded at different stations and in different periods. The main point argued is that fluvial discharge is the key-factor in tidal distortion and tidal bore formation in the system investigated, whereas the low relief of the area would be the main factor contributing to landward tidal incursion. The results show an impressive upward tidal incursion of more than 200 km, including substantial distortion -increasing upstream -of the tidal wave, of which the ebb phase lasts up to 5 hours longer than the flood, including higher flood current velocities as far as 161 km upstream. Generally, only hyposynchronous tidal response was observed. Seasonally, the fluvial discharge varies about 10 times in the Guamá and 4 times in the Capim River. The increase of the fluvial discharge results in an increasing distortion of the tide, besides a weak increase of the attenuation. During high fluvial discharge periods in conjunction with equinoctial tides (e.g. March-April), a tidal bore occurs in the system, also increased by the generally low relief. Therefore, the conclusions include: low relief and the distortion related to high fluvial discharges are the main factors controlling tidal propagation along the system and tidal bore formation. Furthermore, the system could be classified as a tidal river, in which massive regional fresh water input results in virtually non-existent salinity throughout the Guamá-Capim system. O presente estudo teve como objetivo investigar a propagação da maré no sistema fluvial Guamá-Capim, na região amazônica, considerando aspectos hidrológicos e geomorfológicos. Os métodos empregados incluem dados históricos de vazões fluviais e níveis d'água, além de medições próprias de maré em diferentes locais e períodos ao longo do sistema. Os principais pontos defendidos no presente trabalho incluem a vazão fluvial como principal fator para a distorção da maré e consequente formação de pororoca no sistema, assim como o baixo relevo da área seria responsável por incremento na incursão da maré para o continente. Os resultados revelam uma penetração da maré de mais de 200 km, ocorrendo também uma forte deformação da maré, se intensificando gradualmente a montante, resultando em uma vazante até 5 horas mais longa que a enchente 161 km a montante, apresentando também velocidades de enchente levemente superiores, incluindo o decaimento contínuo da altura da maré, intensificado a partir desse ponto. Sazonalmente, a vazão fluvial aumenta 10 vezes no rio Guamá e 4 vezes no rio Capim. Durante períodos de alta descarga, combinados com marés equinociais (e.g. março-abril), o fenômeno da pororoca ocorre no sistema, em associação ao baixo relevo da área. Desta forma as principais conclusões são de que a forte deformação da maré relacionada a altas descargas fluviais e o baixo relevo da área são os fatores preponderantes na propagação da maré no sistema e formação de pororoca. Mais além, o sistema foi classificado como tidal river, onde a enorme descarga de água doce na região costeira amazônica resulta na prática ausência de salinidade no sistema estudado. Assim, seu estudo vem contribuir na definição e classificação de sistemas estuarinos. 2014-10-22T11:58:11Z 2014-10-22T11:58:11Z 2012-12 Artigo de Periódico FREITAS, Paulo T. A.; SILVEIRA, Odete F. M.; ASP, Nils Edvin. Tide distortion and attenuation in an Amazonian tidal river. Brazilian Journal of Oceanography, São Paulo, v. 60, n. 4, p. 429-446, out./dez. 2012. Disponível em: <http://www.scielo.br/pdf/bjoce/v60n4/v60n4a03.pdf>. Acesso em: 30 jun. 2014. <http://dx.doi.org/10.1590/S1679-87592012000400003>. 1982-436X http://repositorio.ufpa.br/jspui/handle/2011/5907 eng Acesso Aberto application/pdf
institution	Repositório Institucional - Universidade Federal do Pará
collection	RI-UFPA
language	eng
topic	Marés Propagação da maré Estuários Medidores de fluxo Hidrodinâmica Descarga fluvial Rios Amazônia brasileira Vazão das marés Sistema fluvial Guamá-Capim
spellingShingle	Marés Propagação da maré Estuários Medidores de fluxo Hidrodinâmica Descarga fluvial Rios Amazônia brasileira Vazão das marés Sistema fluvial Guamá-Capim FREITAS, Paulo Tadeu Amorim Tide distortion and attenuation in an Amazonian tidal river
topic_facet	Marés Propagação da maré Estuários Medidores de fluxo Hidrodinâmica Descarga fluvial Rios Amazônia brasileira Vazão das marés Sistema fluvial Guamá-Capim
description	The present study seeks to evaluate tidal propagation in the Guamá-Capim river system, in the Amazonian region, considering hydrodynamic and geomorphological aspects. Available data sets on fluvial discharge and water level variations were considered, besides several methods of measuring the tides (currents, water levels and discharges) recorded at different stations and in different periods. The main point argued is that fluvial discharge is the key-factor in tidal distortion and tidal bore formation in the system investigated, whereas the low relief of the area would be the main factor contributing to landward tidal incursion. The results show an impressive upward tidal incursion of more than 200 km, including substantial distortion -increasing upstream -of the tidal wave, of which the ebb phase lasts up to 5 hours longer than the flood, including higher flood current velocities as far as 161 km upstream. Generally, only hyposynchronous tidal response was observed. Seasonally, the fluvial discharge varies about 10 times in the Guamá and 4 times in the Capim River. The increase of the fluvial discharge results in an increasing distortion of the tide, besides a weak increase of the attenuation. During high fluvial discharge periods in conjunction with equinoctial tides (e.g. March-April), a tidal bore occurs in the system, also increased by the generally low relief. Therefore, the conclusions include: low relief and the distortion related to high fluvial discharges are the main factors controlling tidal propagation along the system and tidal bore formation. Furthermore, the system could be classified as a tidal river, in which massive regional fresh water input results in virtually non-existent salinity throughout the Guamá-Capim system.
format	Artigo
author	FREITAS, Paulo Tadeu Amorim
author2	SILVEIRA, Odete Fátima Machado da ASP NETO, Nils Edvin
author2Str	SILVEIRA, Odete Fátima Machado da ASP NETO, Nils Edvin
title	Tide distortion and attenuation in an Amazonian tidal river
title_short	Tide distortion and attenuation in an Amazonian tidal river
title_full	Tide distortion and attenuation in an Amazonian tidal river
title_fullStr	Tide distortion and attenuation in an Amazonian tidal river
title_full_unstemmed	Tide distortion and attenuation in an Amazonian tidal river
title_sort	tide distortion and attenuation in an amazonian tidal river
publishDate	2014
url	http://repositorio.ufpa.br/jspui/handle/2011/5907
_version_	1832603755512594432
score	11.755432

Tide distortion and attenuation in an Amazonian tidal river

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