Abstract:Remote sensing has more advantages than the traditional methods of land surface water (LSW) mapping because it is a low-cost, reliable information source that is capable of making high-frequency and repeatable observations. The normalized difference water indexes (NDWIs), calculated from various band combinations (green, near-infrared (NIR), or shortwave-infrared (SWIR)), have been successfully applied to LSW mapping. In fact, new NDWIs will become available when Advanced Land Imager (ALI) data are used as the ALI sensor provides one green band (Band 4), two NIR bands (Bands 6 and 7), and three SWIR bands (Bands 8, 9, and 10). Thus, selecting the optimal band or combination of bands is critical when ALI data are employed to map LSW using NDWI. The purpose of this paper is to find the best performing NDWI model of the ALI data in LSW map. In this study, eleven NDWI models based on ALI, Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM+) data were compared to assess the performance of ALI data in LSW mapping, at three different study sites in the Yangtze River Basin, China. The contrast method, Otsu method, and confusion matrix were calculated to OPEN ACCESS Remote Sens. 2013, 5 5531 evaluate the accuracies of the LSW maps. The accuracies of LSW maps derived from eleven NDWI models showed that five NDWI models of the ALI sensor have more than an overall accuracy of 91% with a Kappa coefficient of 0.78 of LSW maps at three test sites. In addition, the NDWI model, calculated from the green (Band 4: 0.525-0.605 μm) and SWIR (Band 9: 1.550-1.750 μm) bands of the ALI sensor, namely NDWI A4,9 , was shown to have the highest LSW mapping accuracy, more than the other NDWI models. Therefore, the NDWI A4,9 is the best indicator for LSW mapping of the ALI sensor. It can be used for mapping LSW with high accuracy.

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The Qingjiang River

In the current paper, we report the synthesis of three-dimensional (3D) copper sulfide (CuS) with novel tertiary hierarchical architectures prepared by a one-step solvothermal method through the reaction of sulfur powder and solid copper for the first time. In this work, porous copper foam is used as the template. In this material, the primary structure is the multi-structure interchange copper foam precursor, the secondary structure is 10-20 mm cubic solids, and the tertiary structure is interpenetrating flakes with a thickness of 40-50 nm. Owing to the obtained hierarchical structure, the CuS material grows firmly in situ on a 3D copper template. This stable 3D framework will make the recycling of the material into a heterogeneous catalyst facile. This catalyst shows highly efficient heterogeneous catalytic properties in degrading dye-containing solutions, such as methylene blue (MB), rhodamine B (RB), and their mixed solution. The 3D structure of Fenton-like CuS catalysts plays an important role in the degradation process of MB and RB solvents with the help of H 2 O 2 which can yield highly reactive hydroxyl radicals. This catalyst is easy to recycle, and it can be used as a degrading catalyst in highly concentrated dye wastewater because of its low cost, simple operation, and highly efficient properties.