Reconstrução dos padrões de uso da terra na Amazônia, no período 1940-1995, para estudos climáticos e hidrológicos

• Ano de defesa: 2008
• Autor(a) principal: Leite, Christiane Cavalcante
• Orientador(a): Costa, Marcos Heil
• Banca de defesa: Soares Filho, Britaldo Silveira , Costa, José Maria Nogueira da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Meteorologia Agrícola
• Departamento: Agrometeorologia; Climatologia; Micrometeorologia
• País: BR
• Palavras-chave em Português: Uso da terra; Amazônia
• Palavras-chave em Inglês: Land use; Amazon
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA::CLIMATOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1487

Changes in forests, croplands, water ways and the atmospheric composition throughout the world are occurring because of the need for food, fibers, water and housing for over 6 billion people. Croplands, pasturelands, forest plantations and urban areas have expanded in recent decades, accompanied by large increases in energy, water and fertilizer consumption and a considerable loss in biodiversity. Research has shown that land cover and land use changes have caused important modifications in the quantity and quality of water resources, in addition to changes in climate. This generally occurs through changes in the radiation balance at the surface, and in the partitioning of the radiation balance in sensible and latent heat fluxes, causing modifications in the atmospheric circulation and climate. This work aims at creating a historical database of land use for Amazonia, gheographycally explicit in grid, at a 5' x 5' spatial resolution, in the period 1940 - 1995, for climatic and hydrological studies. The first part of this work, and one of the most important, was to construct the municipal digital meshes of Amazonia in each year the agricultural census was accomplished in the period 1940-1995. The construction of the meshes allowed the calculation of the fractions of cropland, natural pasture and planted pasture inside each municipality, for each year of the census, by dividing the census cropland area in a certain year by the area of this municipality, according with its limits on that same year. In a similar way, the fractions used by natural pasture and planted pasture in each municipality were calculated. The second part was to calculate the proportions of each type of land use between 1995 and the years of census, for each comparable minimum area. And the third and last part was to reconstruct the patterns of land use for Amazonia multiplying the resulting maps of the second stage with two classifications of land use for 1995, based on satellite and census data, developed by Cardille et al. [Global Biogeochemical Cycles, 2002] and Ramankutty et al. [Global Biogeochemical Cycles, 2008]. The results showed that the databases of land use in Amazonia, for the period 1940-1985, show some similar patterns in the study area, for example in the states of Tocantins, Goiás and Mato Grosso, both in intensity as in the spatial distribution of agricultural activities. However, in another regions the two databases were different, mainly in the spatial distribution of the pixels with agricultural activities, such as in the states of Amazonas and Rondônia, where they differed, in intensity, and in distribution. When we compared the two databases of land use with the map of land cover produced by the Tropical Rainforest Information Center (TRFIC), based on Landsat images, it was observed that in most of the compared years, especially for State of Rondônia, the database based on Ramankutty et al. [2008] presented a larger number of pixels containing agricultural activities similar to the deforestation areas in the TRFIC maps, mainly along BR 364, area in that the deforestation was better represented in this database. However, when we compared the maps for the State of Pará, the two databases presented the same number of areas similar to the TRFIC maps. The databases constructed in this work have uncertainties related to the fact that they were created by the merge of two different observations systems. However, in spite of those uncertainties, these databases are the first attempt of reconstructing the historical changes of the cropland, natural pasture and planted pasture in Amazonia, using agricultural census data at municipal level. These historical databases will be useful to help to understand the causes of the climatic changes in Amazonia, as well as to investigate the impacts of the historical changes in the land cover and land use in the water resources and climate of Amazonia.