Análise de Dados Maregráficos na Baía de Paranaguá-PR

Abstract

Paranaguá Estuarine System accuretly portrays the complexity of the coastal zone and imposed challenges regarding territorial management: an estuary that contains one of the busiest ports in Brazil and an environmental protection area of ecological importance. This complexity requires the study of the water level in order to efficiently apply solutions to ensure economic development without losing sight of social and environmental issues. The objective of this essay is to study the tide phenomenon in the Paranaguá Bay area, through the analysis of time series of sea level at five tide gauges: Antonina, Ponta do Félix, Cais Oeste, Ilha das Cobras and Galheta. The analysis comprised development and application of processes to remove cleary wrong data, which provided an average reduction of 9,86 % and a maximum of 62,49 % in constituents variance determined by harmonic analysis and an increase in the number of constituents determined in 12 of the 37 series analyzed. Harmonic analysis was performed by the AstgeoTop and PACMARÉ programs. Predominantly semidiurnal behavior was observed in Antonina, Ponta do Félix and Cais Oeste and semidiurnal with inequalities in Ilha das Cobras and Galheta. An analysis of wave reflection in the study area was carried out, concluding that it is likely that this phenomenon contributes to the increase in the amplitude of the main semidiurnal constituents in the bay head. The constituents phase lag between the entrance and the bay head agrees with the shortening in wavelength due to depth reduction. Thompson's optimal low-pass filter made it possible to estimate tide predominance throughout the year, with positive tides in the first semester and negative tides in the second. RV index showed, on average, astronomical effects explained 82% of sea level variation, that is, approximately 18% non-astronomical effects found. The estimate of the monthly Mean Sea Level at Cais Oeste and Galheta stations, which provided the longest sea level series available, was in close agreement with the meteorological constituent Sa, which was also observed for Cananeia - SP, 80 km northeast from the study area. Removing the inverted barometer effect from the observations allowed a 5% reduction in the standard deviation of the residues (one centimeter) for one of the time series obtained at Cais Oeste station. A message adressing positive issues and the report of some discrepancies found will be sent to the provider of the data used in this research, National Oceanografic Database, with the purpose of making a modest contribution to the high quality data made available to the scientific community. Despite the limitations (not long enough time series and little availability of environmental data from other sources, for example), this study reinforces the importance of maintaining tide records for support studies in coastal areas, especially regarding integration of vertical Data.