Papers by Adilson Machado
Morphometric Analysis and Prioritization of Watersheds on the Eastern Coast of the State of Maranhão, Brazil: Planning Strategies and Environmental Management
Esta obra está licenciada com uma Licença Creative Commons Atribuição 4.0 Internacional (CC BY 4.... more Esta obra está licenciada com uma Licença Creative Commons Atribuição 4.0 Internacional (CC BY 4.0). O conteúdo desta obra e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais.
REVISTA EQUADOR
Sensores de satélites ópticos com boa resolução espacial, como Landsat Thematic Mapper (TM) e MSI... more Sensores de satélites ópticos com boa resolução espacial, como Landsat Thematic Mapper (TM) e MSI/Sentinel-2, são importantes fontes de informações para investigações científicas do ambiente, agricultura, silvicultura e desenvolvimento urbano. O presente estudo tem o objetivo de identificação e delimitação das diferentes classes uso e cobertura da terra do da Ilha do Maranhão, buscando comparar a resposta das imagens provenientes dos sensores orbitais OLI/Landsat-8 e MSI/Sentinel-2. A metodologia partiu da obtenção de imagens orbitais da área, passando por etapas de pré-processamento, geração de NDVI, SAVI e classificação supervisionada, bem como a validação da classificação a partir do índice Kappa e Acurácia usuário e acurácia produtor, além da produção dos mapas temáticos. Os produtos NDVI Landsat-8 e Sentinel-2, apresentaram resultados similares, representando de forma satisfatória a vegetação e outros alvos (água, solo exposto e área urbana). Observa-se que após a divisão das c...
Revista Brasileira de Geografia Física
The aim of the present study was to perform a morphodynamic and sedimentary characterization of B... more The aim of the present study was to perform a morphodynamic and sedimentary characterization of Banho Beach and Caúra Beach, which are located in the municipality of São José de Ribamar, state of Maranhão, Brazil (2°33'25"S - 2°33'52"S and 44°02'21"W - 44°03'13"W). Morphodynamic and geological studies were performed on both beaches in campaigns carried out in the dry season (October 2016). Sediment samples were collected along the beach profiles at both beaches for the determination of grain classification and permeability. The direction of the coastal drift current was determined using a red organic fluorescent tracer at Banho Beach. The results showed a greater width of sediments on Banho Beach, with a 624-meter foreshore, whilst Caúra Beach had a width of 105 m, with the advance of the tide at several points, as well as a trough system, sand bar and cliffs. Regarding granulometry, medium-coarse sand was found at Banho Beach and fine sand predom...
Revista Brasileira de Geografia Física, Jan 5, 2023
Watersheds occupy a vulnerable position with regards to issues associated with anthropogenic chan... more Watersheds occupy a vulnerable position with regards to issues associated with anthropogenic changes. The state of Maranhão stands out in Brazil for its water resources. The Watersheds of the Eastern Coast of Maranhão (ECWSM) are located in the Hydrographic Region of the Western Atlantic. The present paper characterizes the physiography of the ECWSM of Maranhão, highlighting the components and natural potential (altimetry, declivity, soils, vegetation, water resources, geology and geomorphology), which were mapped using geotechnologies and secondary data. Thus, this paper provides information for the planning of socioeconomic development programs as well as land management plans. The geology, geomorphology, pedology and vegetation data were obtained from the IBGE database at a scale of 1:250,000. The Digital Elevation Model was obtained from the TOPODATA project. Water resources data were obtained from the IBGE, National Water Agency. The ECWSM analyzed were: the Hydrographic Basin System of the Rivers Itatuaba, Anajatuba, Axuí, Mapari, Periá, Grande and the Hydrographic Basins of the Negro and Preguiças Rivers. The morphological and physical attributes of the ECWSM and the relationships of ecological potential (geology, geomorphology, hydrology and climate), biological exploitation (soil and vegetation) and human actions reveal proxies of the evolution of the Holocene landscape. The natural resources and landscape of Conservation Units within these watersheds form immense nurseries for biological productivity that supports traditional economic activity. The mapping of the ECWSM contributes to the development of effective environmental zoning in the region.
Anais da Academia Brasileira de Ciências
The formation of dense water masses at polar regions has been largely infl uenced by climate chan... more The formation of dense water masses at polar regions has been largely infl uenced by climate changes arising from global warming. In this context, based on ensemble simulations with a coupled model we evaluate the meridional shift of a climate signal (i.e., a cold and fresh water input pulse generated from melting of positive Antarctic sea ice (ASI) extremes) towards the Tropical Atlantic Ocean (TAO). This oceanic signal propagated from Southern Ocean towards the equator through the upper layers due to an increase in its buoyance. Its northward shift has given by the Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) fl ows, that inject cold and fresh mode/intermediate waters from into subtropical basin. The signal has reached low latitudes through the equatorial upwelling and spreads out southwards, through the upper branch of southern subtropical gyre. We concluded that 10 years of coupled simulations was enough time to propagate the climate signal generated by ASI positive extremes melting, which reached TOA around 2 year later. The oceanic connection between Southern Ocean and TAO is indeed established within the timescale analyzed in the study (10 years). Nonetheless, the period needed to completely dissipate the disturbance generated from ASI seems to be longer.
Ambiente e Agua - An Interdisciplinary Journal of Applied Science, 2022
The objective of this research was to characterize the distribution of dissolved nutrients at six... more The objective of this research was to characterize the distribution of dissolved nutrients at six sampling stations in the estuary of the Anil River (ARE) and characterize the bottom sediment. The study area is influenced by a tropical climate and semidiurnal macrotidal regime. Sampling of the surface water and sediment was performed in the main channel at six sampling stations distributed along the estuary in the rainy period (May 9th) and dry period (October 5th) during the spring. Physical variables were collected with the aid of a HANNA HI-8424 multi-parameter probe (water temperature, salinity, pH, dissolved oxygen, and turbidity) and YSI CTD (conductivity, temperature, and depth) probe. A van Veen dredge was used for the collection of bottom sediment from the main channel. The sedimentological results were heterogeneous. Grain size ranged from very fine to medium sand. Dissolved nutrients in the ARE had different sources depending on the season. Continental and fluvial inputs,...
O presente estudo buscou determinar o ciclo anual dos principais campos oceânicos superficiais e ... more O presente estudo buscou determinar o ciclo anual dos principais campos oceânicos superficiais e a variabilidade climatica interanual do Oceano Atlântico Equatorial Ocidental (AEO), de modo a estabelecer relacoes com eventos fortes e moderados de El Nino e La Nina no Oceano Pacifico. Diante da importância da variabilidade climatica dos campos oceânicos superficiais para o clima dos continentes adjacentes, a principal motivacao deste estudo e explorar a variabilidade sazonal da Temperatura Superficial do Mar (TSM), da Salinidade Superficial do Mar (SSM) e das correntes superficiais no Oceano AEO a partir de simulacoes com um modelo numerico de circulacao oceânica regional. Este estudo analisa tambem a variabilidade regional dos principais campos oceânicos superficiais na escala interanual e decenal. O modelo numerico Regional Ocean Modeling System (ROMS) foi utilizado para simular os campos de TSM, SSM, Altura da Superficie do Mar e Velocidade de Corrente em superficie. Os compostos ...
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Papers by Adilson Machado