1. College of Resources and Environmental Engineering, Ludong University, YanTai 264025, China 2. Key Laboratory of Quantitative Remote Sensing Information Technology, Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China
Detecting snow cover information and snow space-time distribution quickly and accurately is a basic problem of ecological environment changes in the resources. Remote sensing technology effectively provides technical support for solving this problem. Normalized difference snow index (NDSI) is an important method for automatic extracting snow cover information using spectral features of snow, which have high reflection in the green band (0.53~0.59 μm) and strong absorption characteristics in short wave infrared band (1.57~1.65 μm). By using Landsat8 OLI images as the data source and according to the spectral characteristics of snow, the authors propose the enhanced normalized difference snow index (ENDSI) based on adding emissivity characteristics of snow in first band B1 (0.433~0.453 μm) and second band B2 (0.450~0.515 μm), and the utilization of this index to extract snow from OLI images. Simulation and case study results show the following characteristics: the sensitivity of ENDSI is stronger than that of NDSI for the snow thickness; with the increase of the thickness of snow, the change of ENDSI value is stronger than that of NDSI; ENDSI can effectively increase the difference between snow and non-snow; it is easy to extract snow from the image with 0.3 as ENDSI threshold and, in this way, snow extraction accuracy is improved.
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