标题：Inferring fluctuations of the aquifer by monitoring the area of small lakes in a brazilian savanna region using a temporal sequence of 50 landsat images
期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2010
卷号：XXXVIII - Part 7B
页码：463-468
出版社：Copernicus Publications
摘要：Water availability is subjected to a complex dynamic involving .uctuation of the aquifer level, itself subject to climatic and edaphic factors as well as land use and land cover. Human pressure can have a drastic effect on the aquifer level, the effect of which are often only noticeable after years of continuous usage. In this article we are using a temporal sequence of 50 Landsat images to study a complex of small lakes in Northern Minas Gerais. Our objective is to quantify the .uctuations of the aquifer for the 1984-2009 period by monitoring the area of these lakes bi-yearly and compare it with the hydric balance to understand its evolution. Having no measurements of the aquifer, we developed a methodology entirely based on remote sensing and meteorological data. Because these lakes are very small, the 30 m resolution of the Landsat data rendered very poor results. Based on the postulate that the water pixels behave like a smooth continuous surface, we increased the resolution to 5 m using minimum curvature interpolation. Two methods were tested for extracting the lake surface pixels: supervised classification and thresholding of the normalized difference water index. The results show that the interpolated Landsat data compared well with a high resolution Ikonos image of the same date and can improved the contouring of water bodies. For extracting the water pixel the classification approach performed better by about 15%. Statistical tests showed that the lakes have been systematically decreasing but that these changes cannot be attributed to climatic factors
关键词：Multi-temporal; Water index; Water level monitoring; Interpolation; Hydrologic Budget
