Navegando por Assunto "Costa - Amapá"

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Acesso aberto (Open Access)
Aplicação de dados multisensor (SAR e ETM+) no reconhecimento de padrões de uso e ocupação do solo em costas tropicais: Costa Amazônica, Amapá, Brasil
(2009) SANTOS, Valdenira Ferreira dos; POLIDORI, Laurent; SILVEIRA, Odete Fátima Machado da; FIGUEIREDO JÚNIOR, Alberto Garcia de
Environmental studies require information on land use and land cover. This paper presents the applicability of multi-sensor satellite data (optical and radar) for land use and land cover on the Amapá coastal plain for mapping and recognition of natural and anthropogenic dynamics. This area is influenced by the Amazon River, by tides (tidal bore) and by the Intertropical Convergence Zone (ITCZ). Anthropogenic processes are associated with water buffalo ranching. The environmental information was acquired from previous data and field observation and was correlated with remote sensing data (JERS-1, RADARSAT-1, image from ETM+ sensor from Landsat 7 and DEM SRTM), digitally processed for multi-sensor, multi-scale and multi-date approach. Eight patterns of land use and land cover were identified (mangrove, "várzea" forest, arbustive vegetation area, freshwater marsh, anthropic field, intertidal plain, estuarine channel and lakes) as well with indication of natural and anthropogenic geomorphic features. The results from the evaluation of remote sensing data and the techniques applied demonstrated the potential of the remote sensing tool for studying environments in highly dynamic tropical coastal areas of difficult access. However, these tools may present some limitations once applied to application to the Amazon coast, which is a region under strong dynamic natural and anthropogenic processes.
Acesso aberto (Open Access)
Avaliação de áreas deposicionais e erosivas em cabos lamosos da zona costeira amazônica através da análise multitemporal de imagens de sensores remotos
(2012) BATISTA, Edmilson das Mercês; SOUZA FILHO, Pedro Walfir Martins e; SILVEIRA, Odete Fátima Machado da
The Cassiporé and Orange mudcapes in the Northern of Brazil constitute a dynamic environment influenced by the Amazon river, where the shoreline changes are subjected to severe processes of progradation and erosion. Optical and microwaves remote sensed images were acquired from 1980 to 2003, and analyzed in a Geographic Information System (GIS), allowing the identification and quantification of prograding and retrograding areas along the shoreline. During this period, the largest erosion rates had occurred next to the Cassiporé Cape, with mean retreat of 27.5 m of linear distance and erosion of 1.37 km² of mangrove area per year. On the other hand, the largest rates of sediment deposition had occurred in the Orange Cape, where the coastal prograded 24.6 m per year, adding 55.86 km² of mangrove area to shoreline in the last 23 years. The progradation mechanisms have determined an accretion in the mangrove vegetation of 50.8% throughout the last three decades. A sedimentary balance carried out in the study area showed that constructive processes (61.3%) are dominant over erosive processes (38.7%).
Acesso aberto (Open Access)
Uso de sensoriamento remoto para identificação e mapeamento do paleodelta do Macarry, Amapá
(Universidade Federal do Pará, 2011-05-11) SANTANA, Laysa de Oliveira; SILVEIRA, Odete Fátima Machado da; http://lattes.cnpq.br/9671710605343277; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
Remote sensing is the science or art of acquiring information about an object or area without any physical contact with him. Applications using remote sensing products have shown that multispectral data of optical and microwave sensors have great potential for discrimination of patterns of use and land cover, geomorphology in the identification of wetland environments and details, especially the coastal areas (Pereira et al. 2003). The study area was chosen because it presents unique morphological characteristics of a delta off - paleodelta - and still be rented for this feature in the Atlantic coast of Amapa, which is still devoid of morphological studies and detailed mapping as compared to the rest Amazon coast, as the island of Marajo, northeastern and northwestern Pará Maranhão. In this work the main objective is to identify and map the morphology of paleodelta this area of study as a tool using the digital integration of multisensor data, in the microwave (Radarsat) and optical (Landsat), and assess, qualitatively, the use of techniques Digital processing of Images from remote sensing sensors in identifying paleodelta study area. To achieve the main goal, the following methodological approach was employed: (a) analysis of product sensors (Landsat-7 ETM +, Radarsat-1 and SRTM) based on digital image processing, (b) data collection in the field, related to topography and recognition of features present in the area, and (3) from the marriage of the products of remote sensing and field data, was developed morphological map of the study area. The digital processing of remote sensing images used in the study generated the following products: three scenes SAR speckle reduction effect and application of adaptive filter type Enhanced Frost, three colored compositions (7R5G3B, and 4R3G1B 5R3G2B) generated from the calculation the OIF (Optimum Index Factor), the product of the best triad OIF (the colored composition 7R4G3B), the product of technical PCA (Principal Component Analysis) in six bands of ETM +, the product SPCA (Selective Principal Component Analysis), hybrid products SAR fused with the best triad OIF and SAR in fusion with the best triad OIF and application enhancement by decorrelation, the product of fusion of SAR with the PCA, the product of the fusion of SAR with the SPCA and the product of a merger of three scenes SAR. Consequently the study of these visual features seven products, which comprise the paleodelta study area, were identified. They are: delta plain (subdivided into the flood plain and tidal flat muddy bottoms), paleochannel, meander bar, tidal bar, levees and tidal channel. The visual interpretation and evaluation of remote sensing products - about the effectiveness in detecting these features - took into account the requirements of chromaticity and textural. It is noteworthy that most of these features is disabled or filled by sediments and poorly consolidated. Thus, it appears that products generated from the digital image processing of each sensor are less effective than the products generated from the integration of sensors when related to the identification of morphological features in the study area, because they are better discriminated products generated from mergers, thus emphasizing that the technique of image fusion with optical images, SAR is effective for discrimination of morphological features and mapping them.