Characterization of the Salar de Uyuni for in-orbit satellite calibration

Field work was carried out on June 8 and 9, 1999 to evaluate the use of the Salar de Uyuni as a test site for in-orbit satellite calibration. A dataset of ten Thematic Mapper (TM) images, from 1988-1997, was used to select three test points based on the analysis of the temporal stability of the reflectance of Salar's surface. Bidirectional reflectance factor (BRF) values of Salar's surface within the precision suitable for vicarious calibration procedures were obtained using a CE313-2/CIMEL radiometer. In spite of seeming visually homogeneous, the BRF values of one test point have presented significative statistical differences with the two others. Atmospheric characterization was possible with a sunphotometer CE317/CIMEL showing the low importance of the atmospheric effects in the image acquisition. The results confirm that the Salar de Uyuni has the characteristics pointed out by many authors as suitable for a vicarious calibration site, specially from April to November because of the reduced rainfall occurrence. The main disadvantages are the difficult access and the critical period for data collecting in the rainy season from November to March. An angular reflectance variation study is recommended in order to evaluate its Lambertian properties.41611461146

In-flight absolute calibration of the Landsat-5 TM on the test site Salar de Uyuni

In Brazil, the increase of the application of quantitative approaches in the natural resources studies using remote sensing technology has required knowledge about the radiometric conditions of remote sensors as the Thematic Mapper (TM) and the Enhanced TM Plus, for instance. The establishment of a correlation between radiometric data and biophysical and geophysical ones has become a frequent need in the Brazilian remote sensing community, and it has increased the demand of calibration coefficients in order to transform digital numbers to physical values like radiance and reflectance. Since the China-Brazil Environmental Remote Sensing Satellite became a reality, the necessity to perform calibration campaigns increased significantly. Following Price and other researcher's suggestions, an in-flight absolute calibration of the Landsat-5 data was carried out in the Salar de Uyuni, Bolivia. It was only possible to determine calibration coefficients for bands TM2, TM3, and TM4 due to the saturation of band TM1 and surface moisture conditions that impacted the TM5 and TM7. The methodology applied here seemed to be sufficient to determine valid calibration coefficients for orbital sensors.42122761276

A produção do lugar de transmissão da leishmaniose tegumentar: o caso da Localidade Pau da Fome na cidade do Rio de Janeiro, Brasil Production of transmission foci for cutaneous leishmaniasis: the case of Pau da Fome, Rio de Janeiro, Brazil

Este trabalho analisa as características de um dos lugares de transmissão de maior relevância da leishmaniose tegumentar na cidade do Rio de Janeiro, Brasil, considerando sua configuração territorial e as relações desta com processos de organização do espaço. Utilizou-se o modelo de análise do processo de ocupação e organização do espaço urbano, em escala local, considerando-se as novas funções adquiridas pelos elementos espaciais expressos por diferentes relações de trabalho, uso do solo e valor da terra. Empregaram-se técnicas de geoprocessamento e de classificação de imagens obtidas por sensoriamento remoto, localização de domicílios e casos de leishmaniose tegumentar, associados a dados qualitativos sobre o processo histórico de ocupação e uso do solo. A análise mostrou áreas com distintas condições de vulnerabilidade, e que mudanças destas condições viabilizaram a produção da epidemia em um determinado período e sua posterior redução. O estudo contribui para o monitoramento da enfermidade em nível local e para a aplicação de medidas eficazes para as ações de vigilância e controle da leishmaniose tegumentar.<br>This study analyzes the characteristics of one of the main foci for cutaneous leishmaniasis transmission in the city of Rio de Janeiro, Brazil, examining its territorial configuration and the relations with spatial organization processes. An analytical model was applied to the process of occupation and organization of urban space on a local scale, considering the new functions acquired by the spatial elements expressed by different work relations, land use, and land value. The study employed geoprocessing techniques and classification of images obtained by remote sensing, localization of households, and cases of cutaneous leishmaniasis, associated with qualitative data on the historical process of land occupation and use. The analysis detected areas with distinct conditions of vulnerability and showed that changes in these conditions allowed production of the epidemic in a given time period and its subsequent reduction. The study contributes to monitoring of the disease at the local level and application of effective measures for cutaneous leishmaniasis surveillance and control