Altimetria por satélite na determinação do nível de reservatórios hídricos
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Data
2020-12-02
Autores
Carvalho, Luciana dos Santos Machado
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A altimetria espacial é uma tecnologia de sensoriamento remoto que, através do uso de radares altimétricos acoplados em plataformas orbitais, permite registrar a topografia da superfície ao longo da via terrestre do satélite. Esta tecnologia foi utilizada inicialmente para o monitoramento dos oceanos e geleiras, mas por possibilitar a cobertura global, apresenta grande potencial de aplicação em estudos de corpos d’água continentais. Apesar de pouco explorada, existem perspectivas de crescimento com as inovações tecnológicas e os lançamentos de satélites previstos para os próximos anos. O objetivo deste estudo foi avaliar a qualidade das medições altimétricas pelos radares altímetros das missões espaciais SARAL e Jason-2, na determinação dos níveis de reservatórios da região Sudeste do Brasil, a qual apresenta características diferentes das regiões comumente analisadas, como a bacia Amazônica. O estudo foi realizado no período da crise hídrica que atingiu o Estado de São Paulo, entre os anos de 2014 e 2016, quando foram registradas grandes variações dos níveis de água desses reservatórios. Para a validação dos dados altimétricos, foram utilizadas as medidas de níveis de água produzidas pelas estações convencionais (in situ) dos reservatórios de Atibainha, Paraibuna e Jaguari-Jacareí comparadas às obtidas pela altimetria espacial, realizada a partir da criação de estações virtuais (EV) e suas respectivas séries temporais, por meio do cálculo do Root Mean Square (RMS). Para o reservatório de Paraibuna os valores RMS foram de 0,20 e 0,82 m para a missão altimétrica SARAL e 0,84 e 1,05 m para a Jason2; para os reservatórios de Atibainha e Jaguari-Jacareí, os valores de RMS foram de 0,73 m e de 1,13 m respectivamente, ambos para a missão SARAL. Os resultados obtidos com as estações altimétricas virtuais foram similares às registradas pelas estações in situ, indicando que as informações da altimetria espacial podem contribuir nos processos de caracterização e monitoramento dos recursos hidrológicos, principalmente em áreas de difícil acesso ao monitoramento. Para divulgar essa informação científica, foi desenvolvido um portal na internet para disponibilização das séries de dados altimétricas obtidas nesse estudo.
Spatial altimetry is a remote sensing technology that, through the use of altimetric radars coupled to orbital platforms, allows to register the surface topography along the satellite's terrestrial path. This technology was initially used to monitor the oceans and glaciers, but because it allows global coverage, it has great potential for application in studies of continental water bodies. Although little explored, there are prospects for growth with technological innovations and the launch of satellites planned for the coming years. The aim of this study was to evaluate the quality of altimetric measurements by the altimeter radars of the SARAL and Jason-2 space missions, in determining the levels of reservoirs in the Southeast region of Brazil, which has different characteristics from the regions commonly analyzed, such as the Amazon basin. The study was carried out in the period of the water crisis that hit the State of São Paulo, between the years 2014 and 2016, when large variations in the water levels of these reservoirs were recorded. For the validation of altimetric data, measurements of water levels produced by conventional stations (in situ) of the Atibainha, Paraibuna and Jaguari-Jacareí reservoirs were used compared to those obtained by spatial altimetry, performed from the creation of virtual stations (EV ) and their respective time series, by calculating the Root Mean Square (RMS). For the Paraibuna reservoir, the RMS values were 0.20 and 0.82 m for the SARAL altimetric mission and 0.84 and 1.05 m for the Jason-2; for the Atibainha and Jaguari-Jacareí reservoirs, the RMS values were 0.73 m and 1.13 m respectively, both for the SARAL mission. The results obtained with the virtual altimetric stations were similar to those recorded by the in situ stations, indicating that the spatial altimetry information can contribute to the processes of characterization and monitoring of hydrological resources, especially in areas with difficult access to monitoring. To disseminate this scientific information, an internet portal was developed to make available the series of altimetric data obtained in this study
Spatial altimetry is a remote sensing technology that, through the use of altimetric radars coupled to orbital platforms, allows to register the surface topography along the satellite's terrestrial path. This technology was initially used to monitor the oceans and glaciers, but because it allows global coverage, it has great potential for application in studies of continental water bodies. Although little explored, there are prospects for growth with technological innovations and the launch of satellites planned for the coming years. The aim of this study was to evaluate the quality of altimetric measurements by the altimeter radars of the SARAL and Jason-2 space missions, in determining the levels of reservoirs in the Southeast region of Brazil, which has different characteristics from the regions commonly analyzed, such as the Amazon basin. The study was carried out in the period of the water crisis that hit the State of São Paulo, between the years 2014 and 2016, when large variations in the water levels of these reservoirs were recorded. For the validation of altimetric data, measurements of water levels produced by conventional stations (in situ) of the Atibainha, Paraibuna and Jaguari-Jacareí reservoirs were used compared to those obtained by spatial altimetry, performed from the creation of virtual stations (EV ) and their respective time series, by calculating the Root Mean Square (RMS). For the Paraibuna reservoir, the RMS values were 0.20 and 0.82 m for the SARAL altimetric mission and 0.84 and 1.05 m for the Jason-2; for the Atibainha and Jaguari-Jacareí reservoirs, the RMS values were 0.73 m and 1.13 m respectively, both for the SARAL mission. The results obtained with the virtual altimetric stations were similar to those recorded by the in situ stations, indicating that the spatial altimetry information can contribute to the processes of characterization and monitoring of hydrological resources, especially in areas with difficult access to monitoring. To disseminate this scientific information, an internet portal was developed to make available the series of altimetric data obtained in this study
Descrição
Palavras-chave
Altimetria espacial, Hidrologia, Monitoramento hídrico, Spatial altimetry, Hydrology, Monitoring, Water levels, Reservoirs, Sensoriamento remoto, Desenvolvimento de recursos hídricos