高分辨率SAR影像提取冰川面积与冰面河

Extraction of Glacier Area and Supraglacial Rivers Using High-resolution SAR Imagery

冰川面积变化是冰川积累与消融的直接体现,与气候变化密切相关。遥感的方法可以为冰川的轮廓及面积监测提供可靠手段,但常用的光学遥感容易受到冰川区多变气象条件的影响。合成孔径雷达(SAR)不受天气影响,尤其是高分辨率SAR影像能够提供冰川表面丰富的细节特征,更好地监测冰川变化。应用相位一致性方法和快速行进法相结合的方法提取冰川轮廓和表面纹理。依据提取的冰川轮廓计算的冰川面积误差在5%以下,表明该方法能够准确地提取冰川面积。同时,在高分辨率SAR图像上,利用提取的冰川表面纹理信息可以有效监测到光学图像上难以识别的冰面河,而冰面河与冰川中长期消融密切相关,提取的冰面河信息将为冰川监测提供一种新的视角。

The change of glacier area is the embodiment of the accumulation and ablation of glaciers,and it is closely related to the change of climate.The method of remote sensing provides reliable approach for monitoring glacier outlines and area,but the common method of optical remote sensing is easily affected by the changeable weather conditions in glacier area.Synthetic Aperture Radar(SAR)is not affected by the weather conditions,especially the high-resolution SAR imagery can provide abundant details on glacier surface and monitor the change of glacier better.In this paper,phase congruency method and fast marching method are used simultane⁃ously to extract the glacier outlines and surface texture.The error of glacier area calculated from the extraction of glacier outlines was less than 5%,so it indicated that the method could extract glacier area accurately.Mean⁃while,the extraction of glacier surface texture can be used to monitor effectively the supraglacial rivers,which is hard to visible in optical imagery,but is visible in high-resolution SAR imagery.Supraglacial rivers are close⁃ly related to medium and long term ablations of glacier,and they offer a new perspective for glacier monitoring.