Navegando por Assunto "Coastline"

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Acesso aberto (Open Access)
Análise integrada da paisagem e processos de erosão costeira na ilha de Atalaia, Salinópolis, Pará
(Universidade Federal do Pará, 2024-03-27) SOUZA, Ewerton Müller da Silva; ANDRADE, Milena Marília Nogueira de; http://lattes.cnpq.br/1930321094483005; https://orcid.org/0000-0001-5799-7321
The study aims to analyze the landscape and erosion susceptibility processes on Atalaia Island, Salinópolis, Pará, as a basis for coastal management policies. The objective unfolds in examining the coastline position between 2002 and 2022, identifying coastal dynamics through geoindicators, analyzing landscape units, and the degree of susceptibility to erosion on the island. To achieve the objectives, the study area was divided into three sectors: Espadarte, Atalaia, and Sofia. The materials and methods used include satellite images for a twenty-year multi-temporal analysis, with polygon change analysis techniques, areal and linear rates. For this assessment of coastal changes, the Digital Shoreline Analysis System (DSAS) plugin was used in the Geographic Information System environment of ArcMap 10.5. The use of geoindicators was granted through field sheets with the identification of natural or anthropogenic elements that pointed to the movement of the coastline. For the landscape analysis, the theoretical basis of landscape geoecology and the use of geoprocessing to generate a map of landscape units were used. The study revealed areas of high susceptibility with 47,798m², mainly in sector A, in this sector, geoindicators such as the front strip of vegetation modified by erosion (44) and the presence of retaining walls and other constructions in contact with the beach arch or on the surface of estirance (64) stand out. The areas of moderate susceptibility were present, prominently in Sector B, with an area of 66,950m², in this sector, the geoindicators of water/sewage piping or energy poles, located on the beach arch in a situation of destruction by physical agents (54) and the presence of retaining walls and other constructions in contact with the beach arch or on the surface of estirance (62) stand out. The areas of low susceptibility to erosion were present, most evidently, in Sector C, with an area of 341,274.1m², in this sector, the geoindicator related to the width of the post-beach/sandy berm surface (70) stands out. The results of the landscape analysis allowed the understanding of the structure and functioning of the fluvio-marine plain, urban areas, open areas, moving dunes, and beach and post-beach. The investigation offers a dynamic perspective on the erosion processes of Atalaia Island from the employed methodology, thereby, the results indicate the need for more effective coastal management strategies, underlining the importance of an integrated approach that considers both physical and socioeconomic aspects to mitigate adverse impacts on local communities and the ecosystem.
Acesso aberto (Open Access)
Evolução multitemporal da linha de costa (1972-2040) do município de Soure, Ilha do Marajó (Amazônia - Brasil)
(Universidade Federal do Pará, 2021-11-11) MENEZES, Rafael Alexandre Alves; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; https://orcid.org/0000-0001-7850-1217
Exogenous agents that act in the Coastal Zone (ZC) act as morphological modelers of the CoastLine (LC) and this action modifies the erosive and accretive scenario of the LC over time. To assess these temporal changes in the ZC, remote sensing (SR), from orbital remote sensors, is an opening that makes it possible to identify these variations, where the main objective around the world is the management and protection of these coastal areas. Thus, the present composition aims to present the evolution of the LC line during the period 1972-2020 (48 years) and estimate the evolution of the LC for the years 2030 and 2040 in the ZC of the Soure municipality, located in the northeastern part (NE) of the Marajó island (Pará-Eastern Amazon), inserted in the Pará Estuarine Coastal Zone (ZCEP), conditioned by the hydrodynamics of the South channel of the Amazon River and by the estuary of the Pará River. A set of 6 images from a time series of the satellite were acquired: Landsat 1 (MSS) from 1972 and 1994 (bands 7.6.5 and 5.4.3, respectively), Landsat 5 (TM) from 1985, 2004, 2009 ( bands 5.4.3), with a spatial resolution of 30m, and Landsat 8 (OLI) 2020 (bands 6.5.4.8), with a spatial resolution of 15 m after the fusion of band 8 (panchromatic), being obtained from the USGS (United States Geological Survey) site, all already georeferenced and geoprocessing techniques for: a) LC delimitation: where it was created from semi-automatic methods combined with manual methods, using the normalized water difference index (NDWI) technique; b) DSAS version 5.0 (v5.0), being used to compose the LC analysis hrough this tool: NSM, EPR and LRR, version v5 brings the Kalman Filter, which was used to calculate the future estimate in the LC for the years 2030 and 2040. As a result, it was identified that in sectors I and II (southern channel of the Amazon River), accretion predominates, in sector III (Maguari Cape) it is where it obtained the highest accretion rates, and in sector IV the accretion process predominates with a tendency erosive, sector V erosion predominates. These data are linked to the total number of 654 transects comprising an average distance of 214.4 m, where the mean retreat is indicated with a negative rate of - 179.5 m and a positive rate of 451.9 m. For the years 2030 and 2040, the trend is that this process will continue, where the greatest coastal retraction, around 271.46 m, will be in the Northeast (NE) (sector II), and a CL advance of 625.26 m in sector III.