基于合成孔径雷达影像估计慕士塔格峰地区冰川速度场

Glacier Surface Flow Velocity Field Estimation Using SAR Images of Muztag Ata

冰川速度是冰川学研究中的一个重要参数,遥感方法为获取冰川表面速度提供了一种有效的手段。由于慕士塔格峰地区常年有云覆盖,不能为速度提取提供足够多数量的光学影像。但是,基于SAR影像对偏移量的提取算法为该地区冰川流速的测量提供了一个有效的途径。分别获取两幅雷达影像(ALOS/PALSAR)距离向和方位向的偏移,通过信噪比和相关系数选择可信点,然后通过整体拟合的方法去除雷达图像整体偏移,得到与冰川运动相关的偏移信号。首次得到了慕士塔格峰地区冰川表面完整的速度分布情况,依据该地区的速度大小分布特点,对慕士塔格峰四周冰川进行了划分。并进一步分别分析了该地区冰川在距离向和方位向速度大小与地形的关系,表明速度的大小与地形具有直接的相关性。结果表明,基于SAR影像对的偏移量测量为冰川研究提供了一个有效的方法和手段。

The surface velocities of glacier are important parameters in the study of glaciology. Remote sensing provides an effective tool to acquire the glacier surface flow velocity field. Because of all the year round in the Muztag Ata glacier , always there is cloud cover, the number of optical images to derive glacier velocities is not sufficient. However, procedure based on displacement of SAR images provides an useful method to estimate glacier velocity. The registration offsets of two ALOS/PALSAR images in both slant-range and azimuth direction are estimated, trusted points are selected by using signal-to-noise ratio and correlation coefficient matrix, the overall offset of the radar images is removed by the fitting , so the displacement related to glacier flow is obtained, finally the velocity distribution on the surface of the glacier can be calculated. Complete surface velocity distribution of Muztag Ata glacier is acquired for the first time. Based on the velocity distribution characteristics of the Muztag Ata glacier, the division of glaciers is made. The relationship between surface velocities of glacier and topography is further analyzed, which shows that there is direct correlation between them. It is concluded that displacement measurements based on SAR images can provide effective methods to ice and glaciers research.