Navegando por Assunto "Ambientes costeiros"

Agora exibindo 1 - 2 de 2

Acesso aberto (Open Access)
Análise de imagens Landsat ETM, Radarsat-1 e modelos numéricos de terreno para o mapeamento dos índices de sensibilidade ambiental ao derramamento de óleo na costa de manguezais do nordeste do Pará
(Universidade Federal do Pará, 2006) BOULHOSA, Messiana Beatriz Malato; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
Accidents related to exploration and oil transport are a threat to coast zones araund the world. Oil spills are an ecological disaster that may cause irreparable damage to the environment affecting living beings that live in these coast zones and also the local economy. Characterizing coast environments is very complex because of the many limiting factors during the mapping process. When it comes to humid tropical environment, like in Pará northeast coast, it gets worse because this area is typically dominated by macro tide. First of all, the macro tide plain creates low areas where informations about the relief are, most of times, scarce and the plain metric representation is dominant. Secondly, the tide variations with its vertical and horizontal moving produces strong changes on the sediment coast environment limits. Thirdly, the geomorphological modifications in the coast areas are intense and fast. Towards this context, the objective of this master’s degree dissertation is to create a map of the coast environment and a rating map of the environmental sensitivity about the oil spills in a certain part of Pará state northeast coast. The methodology consisted on processing digital images from remote sensors in the range of optical (Landsat ETM +7) and microwave (RADARSAT–1 Wide-1) associated to data from the SRTM (shuttle radar topographic mission) digital model of elevation, and to the field data collected in SIG (geographical information system) environment, providing an integrated analysis of the spectral, geomorphological, altimetrical and sedimentological characteristics of the coastal environments in cartographic georeferenced bases. The most important results of this dissertation allowed: 1) The evaluation of the potential of the images Landsat ETM +7, RADARSAT-1 and of the multi sensors fusion products used for identifying the coastal environment and the Environment Sensitivity Rates (ISA) of oil spills in this areas 2) Recognizing and describing five main morphological unities and fourteen sub unities: Coastal Plateau, Tide Plain, Coastal Plain and Alluvial Plain 3) Identifying and classifying eight unities of Environmental Sensitivity Rates (ISA) for the Amazon coast zone which are: ISA 1B – support wall; ISA 3B – exposed scarps with declivity to the sand; ISA 9B – sand bank and plains of tidal vegetable mudflats; ISA 9C – hypersalt herbaceous fields, ISA 10A – salt and salobre herbaceous fields; ISA10C – Mangrove; ISA 10D – Lea; 5) creation of the Environmental Sensitivity Rates map to oil spill of the studied area. The using of remote sensors techniques and SIG proved to be an important tool for recognizing and analyzing coast environments and for generating maps to coast environments and to environmental sensitivity rates to oil spills in the northeast coast of Pará.
Acesso aberto (Open Access)
Análise integrada da paisagem para avaliação da vulnerabilidade à perda de solo das margens da Baía de Marajó, estado do Pará
(Universidade Federal do Pará, 2011-11-30) GUIMARÃES, Ulisses Silva; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
Marajó Bay is part of the Coastal Zone in the Amazon estuary, and it constitutes a form of "V" with intensive processes of erosion and progradation. The bay shores are the object of this study, from the west coast, represented by the west coast by Salvaterra and Soure municipalities, to the east coast of Mosqueiro Island. The purpose is to analyze the coastal environments adjacent to the Marajó Bay, with a systemic and integrated approach using thematic databases (geology, geomorphology, pedology, climatology and Use and Land Cover) and remote sensing images (Landsat TM 5 and MDE SRTM) to prepare maps syntheses of landscape units and vulnerability to loss of soil as a subsidy to coastal management. The main steps of this methodology are: i) atmospheric correction by dark-object subtraction, geometric correction by orthorectification, with supervised classification algorithm Spectral Angle Mapper (SAM) through training samples to map the Use and Land Cover; ii) compilation, adaptation and classification to improve data of morphology; iii) development of derivatives geomorphometric; and, iv) integration of the thematic basis for map algebra, with an overlap equation for synthesis of the landscape units maps and another equation for the preparation of the arithmetic average map of vulnerability to loss of soil. The Marajo Bay shores have mostly the unit of Fields with 17.61% of the study area (50,483.16 ha), maximum altimetry of 58 m, the topography is flat and smooth, the relief were overwhelmingly straight and planar. The integrated data indicate that the pedogenetic processes prevail in only 3.58% (10,231.38 ha) of the study area. The areas in balance between morphogenic and pedogenetic processes correspond to 3.75% (10,737.63 ha), while morphogenesis is prevalent in 42.40% (121,317.39 ha). The superiority of morphogenic units shows the hazard of coastal environments per surface mechanisms, how substrate desegregation and erosion by processes of runoff and mass displacement.