极化合成孔径雷达探测冰川表碛理论与方法研究

项目名称： 极化合成孔径雷达探测冰川表碛理论与方法研究

项目编号： No.41471307

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 黄磊

作者单位： 中国科学院遥感与数字地球研究所

项目金额： 76万元

中文摘要： 表碛是覆盖在冰川消融区表面的碎石、碎屑等混合物，在山地冰川区广泛存在.因其与周边非冰川区地面在可见光－近红外波段光谱特性相似，很难在遥感图像上识别，是目前冰川制图和监测的一大瓶颈。另外，表碛的厚度对于冰川的物质平衡具有重要影响，较薄的（几个厘米）表碛会吸收热量加快冰川的消融，而较厚的表碛会阻滞热量传播并减缓冰川消融。合成孔径雷达（SAR）几乎不受云雾等气象条件影响，对地表湿度、粗糙度敏感，且具有一定的穿透性，对冰川探测具有很大潜力。本课题将研究极化SAR探测冰川表碛边界和厚度的理论与方法：研究不同微波波段下表碛的散射机制；筛选SAR图像区分表碛与周边地物的典型特征，结合参考入射角度的新型分类算法，实现表碛覆盖型冰川高精度分类；研究SAR对表碛厚度的探测能力和探测方法；综合冰川表面变化与表碛厚度分布，建立遥感监测表碛覆盖型冰川消融状态与物质平衡的新模式。

中文关键词： 冰川制图；冰川监测；雷达遥感；表碛

英文摘要： Debris is mainly composed of the fragments of broken stones, which distributes widely in the ablation zones of mountain glaciers. Automatic detection of debris on remotely sensed images is difficult because its spectral characteristics are similar to those of the surrounding ground, which makes it a bottleneck while using optical remotely sensed images mapping. The debris plays an important role in glaciers mass balance. When the thickness of debris cover is small (about several centimeters), the debris accelerates ice thawing because of the increased absorption of solar energy by low-albedo and rapid heat transmission; as the thickness increases, the debris decreases ice melting because thicker debris hampers heat transmission and decreases ice melting. Synthetic aperture radar (SAR) is a more useful and promising tool for mountain glacier monitoring because it is sensitive to subtle wetness and roughness variation of snow and ice. Additionally, cloud cover has little influence on SAR data acquisition. This subject makes research on supraglacial debris mapping and its thickness estimation using polarimetric SAR. The topics includes: research on scattering methanism of the debris; accurate classification by combing image features and incident angle-related classification method; method on detection of debris thickness; new pattern on mass balance estimation of the debris covered glaciers based on glacier surface changes and debris thickness.

英文关键词： Glacier mapping;Glacier monitoring;Radar remote sensing;Debris