Caracterização geomorfométrica multiescala de modelos digitais de terreno.

O estudo das formas de relevo através da geomorfometria ciência que quantifica as superfícies topográficas demanda que múltiplas escalas sejam consideradas simultaneamente. Esse fato soma-se à continuidade espacial inerente à topografia, a qual raramente apresenta limites naturais abruptos, para conceder um caráter vago às formas de relevo. Essa dupla vagueza, no entanto, é raramente abordada de forma explícita em trabalhos científicos que, usualmente, valem-se de limiares e definições subjetivas e arbitrárias para descreverem o relevo. Dentro desse contexto, o trabalho apresenta um método inovador de caracterização geomorfométrica multiescala de modelos digitais de terreno (MDTs). A abordagem proposta baseia-se no método de extração de feições morfométricas de Wood (1996), mas o modifica em um número de maneiras: (i) expandindo o número de classes identificadas; (ii) transformando-o em um sistema fuzzy, cujos conjuntos fuzzy são parametrizados automaticamente e; (iii) limitando localmente a escala máxima de análise de maneira não-supervisionada. Como resultado, obtém-se um mapa de feições fundamentais e um mapa de escalas fundamentais que, juntos, sintetizam a estrutura multiescala das superfícies. Além disso, são produzidos mapas de pertinências fuzzy e de índice de confusão para cada escala analisada, assim como versões multiescala dos mesmos. Para avaliar a transferibilidade e o caráter não-supervisionado do método, foram analisados cinco MDTs oriundos de bases de dados distintas, com diferentes resoluções e extensões espaciais, compreendendo regiões continentais, do fundo dos oceanos e do planeta Marte. Os resultados obtidos foram avaliados em relação à utilização de escalas e parametrizações fixas, atestando a capacidade do método de empreender caracterizações geomorfométricas mais completas do que abordagens convencionais. Duas aplicações foram ainda propostas: a parametrização geomorfométrica multiescala e o desenvolvimento de uma assinatura morfométrica multiescala, demonstrando claros caminhos para a continuidade da pesquisa. Como conclusão geral, não obstante a algumas limitações apontadas, considerou-se que o trabalho apresentado alcançou seu objetivo de prover a caracterização geomorfométrica multiescala de modelos digitais de terreno.

Environmental regulation, technology adoption and structural transformation: evidence from Brazilian sugarcane industry

We estimate the effects of the adoption of mechanized agriculture led by a new environmental regulation on structural change of local labor markets within a large emerging country, Brazil. In 2002, the state of S\~{a}o Paulo passed a law outlying the timeline to end sugarcane pre-harvest burning in the state. The environmental law led to the fast adoption of mechanized harvest. We investigate if the labor intensity of sugarcane production decreases; and, if so, if it leads to structural changes in the labor market. We use satellite data containing the type of sugarcane harvesting -- manual or mechanic harvest -- paired with official labor market data.%, also geomorphometric data base for our instrumental variable correction. We find suggestive evidence that mechanization of the field led to an increase in utilization of formal workers and a reduction in formal labor intensity in the sugarcane sector. This is partially compensated by an increase in the share of workers in other agricultural crops and in the construction and services sector. Although we find a reduction in employment in the manufacturing sector, the demand generated by the new agro-industries affected positively the all sectors via an increase in workers' wage.

Aspectos fisiográficos do município de Rio Claro - SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da fragilidade à erosão das margens do reservatório de Ilha Solteira - SP, utilizando as geotecnologias como ferramentas de análise ambiental

Pós-graduação em Engenharia Civil - FEIS

Contribuição metodológica ao estudo da dissecação e energia do relevo: proposta e avaliação de técnicas computacionais

Pós-graduação em Geociências e Meio Ambiente - IGCE

Classificação automatizada do relevo a partir de parâmetros morfométricos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ambientes de confluência no contexto da rede de drenagem: exemplo da bacia hidrográfica do rio Ivaí - estado do Paraná

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Classificação automatizada do relevo a partir de parâmetros morfométricos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ambientes de confluência no contexto da rede de drenagem: exemplo da bacia hidrográfica do rio Ivaí - estado do Paraná

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Surface fitting in geomorphology - examples for regular-shaped volcanic landforms

In nature, several types of landforms have simple shapes: as they evolve they tend to take on an ideal, simple geometric form such as a cone, an ellipsoid or a paraboloid. Volcanic landforms are possibly the best examples of this ?ideal? geometry, since they develop as regular surface features due to the point-like (circular) or fissure-like (linear) manifestation of volcanic activity. In this paper, we present a geomorphometric method of fitting the ?ideal? surface onto the real surface of regular-shaped volcanoes through a number of case studies (Mt. Mayon, Mt. Somma, Mt. Semeru, and Mt. Cameroon). Volcanoes with circular, as well as elliptical, symmetry are addressed. For the best surface fit, we use the minimization library MINUIT which is made freely available by the CERN (European Organization for Nuclear Research). This library enables us to handle all the available surface data (every point of the digital elevation model) in a one-step, half-automated way regardless of the size of the dataset, and to consider simultaneously all the relevant parameters of the selected problem, such as the position of the center of the edifice, apex height, and cone slope, thanks to the highly performing adopted procedure. Fitting the geometric surface, along with calculating the related error, demonstrates the twofold advantage of the method. Firstly, we can determine quantitatively to what extent a given volcanic landform is regular, i.e. how much it follows an expected regular shape. Deviations from the ideal shape due to degradation (e.g. sector collapse and normal erosion) can be used in erosion rate calculations. Secondly, if we have a degraded volcanic landform, whose geometry is not clear, this method of surface fitting reconstructs the original shape with the maximum precision. Obviously, in addition to volcanic landforms, this method is also capable of constraining the shapes of other regular surface features such as aeolian, glacial or periglacial landforms.

Geology and landslide geomorphology of the Burpee Hills, Skagit County, Washington, USA

Landforms within the Skagit Valley record a complex history of land evolution from Late Pleistocene to the present. Late Pleistocene glacial deposits and subsequent incision by the Skagit River formed the Burpee Hills terrace. The Burpee Hills comprises an approximately 205-m-thick sequence of sediments, including glacio-lacustrine silts and clays, overlain by sandy advance outwash and capped by coarse till, creating a sediment-mantled landscape where mass wasting occurs in the form of debris flows and deep-seated landslides (Heller, 1980; Skagit County, 2014). Landslide probability and location are necessary metrics for informing citizens and policy makers of the frequency of natural hazards. Remote geomorphometric analysis of the site area using airborne LiDAR combined with field investigation provide the information to determine relative ages of landslide deposits, to classify geologic units involved, and to interpret the recent hillslope evolution. Thirty-two percent of the 28-km2 Burpee Hills landform has been mapped as landslide deposits. Eighty-five percent of the south-facing slope is mapped as landslide deposits. The mapped landslides occur predominantly within the advance outwash deposits (Qgav), this glacial unit has a slope angle ranging from 27 to 36 degrees. Quantifying surface roughness as a function of standard deviation of slope provides a relative age of landslide deposits, laying the groundwork for frequency analysis of landslides on the slopes of the Burpee Hills. The south-facing slopes are predominately affected by deep-seated landslides as a result of Skagit River erosion patterns within the floodplain. The slopes eroded at the toe by the Skagit River have the highest roughness coefficients, suggesting that areas with more frequent disturbance at the toe are more prone to sliding or remobilization. Future work including radiocarbon dating and hydrologic-cycle investigations will provide a more accurate timeline of the Burpee Hills hillslope evolution, and better information for emergency management and planners in the future.