基于WorldView-2的冰面水体增强指数构建及精细化提取

冰面水体是冰盖物质平衡的重要组成部分，在全球气候及环境变化研究中发挥着重要的作用。本文以格陵兰岛北部为研究区，选取该研究区消融期内不同时相的WorldView-2影像，对区域内典型地物统计分析其光谱特性，构建了针对冰面水体的归一化水体增强指数NEWI（Normalized Enhanced Water Index。依据影像上地物分布规律和直方图图形特征，对冰雪混合物和冰面水体边缘地带灰度值相似的模糊区域定位，增强区域间地物对比度，提取出冰面水体的精细范围。实验结果表明，本研究所提出的指数有效凸显了冰面水体与非水体的反射率差异，与常用的水体指数NDWI等相比，在冰川环境下，提高区分度方面优势明显。通过精度评价可知，本文方法所提取出的冰面水体精细化程度高，提取结果完整，错误率低。本研究对冰面水体信息增强及精细化提取具有重要参考价值。

The construction of Normalized Enhanced Water Index and the extraction of Glacial Water based on WorldView-2 imagery

As an important part of the mass balance of the ice sheet, the ice surface water not only reflects the diversity of polar environmental changes, but also plays an important role in the study of global climate and environmental changes. In this paper we choose northern Greenland as the research area, In this study, a Normalized Enhanced Water Index (NEWI) was constructed based on the high-precision WorldView-2 images of different phases during the ablation period in northern Greenland. The spectral characteristics of the images were statistically analyzed for the typical features in the study area. The fuzzy areas with similar gray values of thin sea ice and shallow ice water bodies were located according to the distribution rules of ground objects and histogram graphic features of the images, so as to enhance the contrast of ground objects between the regions, and finally extract the fine range of water bodies on the ice surface. Experimental results show that the proposed index effectively highlight the ice water with the water of the reflectivity difference, compared with the commonly used water index NDWI, etc, especially in shallow water, improve the degree of differentiation with other object has obvious advantages, and the precision evaluation show that extracted by the method has higher degree of refinement compared with other methods, the ice water can get complete ice water effectively.