Flow of Glaciar Moreno, Argentina, from repeat-pass Shuttle Imaging Radar images: comparison of the phase correlation method with radar interferometry
Flow of Glaciar Moreno, Argentina, from repeat-pass Shuttle Imaging Radar images: comparison of the phase correlation method with radar interferometry
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DOI：
10.3189/s0022143000003075
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发表时间：
1999-01-01
影响因子：
3.4
通讯作者：
Rignot, E
中科院分区：
文献类型：
--
作者：
Michel, R;Rignot, E
阿根廷莫雷诺冰川的高分辨率雷达图像由航天飞机成像雷达 C (SIR-C) 于 1994 年 10 月 9 日至 10 日在 24 厘米波长（L 波段）获取，用于通过干涉测量和相位相关方法绘制冰川速度图。干涉冰速的精度为1.8 cm d(-1) (6 m a(-1)) (1 sigma)。相位相关法以 14 cm d(-1) (50 m a(-1)) 的精度测量冰速，图像数据间隔 1 天采集，样本间距为 6 m。平均应变率的测量精度为 10(-4) d(-1)，样本间距为 240 m，采用相位相关法，采用雷达干涉法，测量精度为 10(-5) d(-1)。相位相关法的精度不如雷达干涉测量法，但它在快速流动的区域表现更好，对冰川散射的时间变化更稳健，并且仅用一对图像即可测量二维冰川速度。利用这项技术，我们发现莫雷诺冰川在末端山谷的流速为 400 m a(-1)，在崩解前缘的流速为 800 m a(-1)，与十年前记录的速度一致。假设目前处于稳态条件，将 SIR-C 测量的垂直应变率与先前的质量消融数据相结合，以估计冰川厚度和冰流量。计算得出的流量在 300 m 海拔处为 0.6 +/- 0.2 km(3) 冰 a(-1)，在平衡线海拔 (1150 m) 处为 1.1 +/- 0.2 km3 冰 a(-1)，从而产生 6 +/- 1 m 冰 a(-1) 的平衡积累。
High-resolution radar images of Glaciar Moreno, Argentina, acquired by the Shuttle Imaging Radar C (SIR-C) on 9 and 10 October 1994 at 24 cm wavelength (L-band), are utilized to map the glacier velocity both interferometrically and using the phase correlation method. The precision of the interferometric ice velocities is 1.8 cm d(-1) (6 m a(-1)) (1 sigma). The phase correlation method measures ice velocity with a precision of 14 cm d(-1) (50 m a(-1)) with image data at a 6 m sample spacing acquired 1 day apart. Averaged strain rates are measured with a precision of 10(-4) d(-1) at a 240 m sample spacing with the phase correlation method, and 10(-5) d(-1) with radar interferometry. The phase correlation method is less precise than radar interferometry, but it performs better in areas of rapid flow, is more robust to temporal changes in glacier scattering and measures the glacier velocity in two dimensions with only one image pair. Using this technique, we find that Glaciar Moreno flows at 400 m a(-1) in the terminal valley and 800 m a(-1) at the calving front, in agreement with velocities recorded a decade ago. Assuming steady-state now conditions, the vertical strain rates measured by SIR-C are combined with prior data on mass ablation to estimate the glacier thickness and ice discharge. The calculated discharge is 0.6 +/- 0.2 km(3) ice a(-1) at 300 m elevation, and 1.1 +/- 0.2 km3 ice a(-1) at the equilibrium-line elevation (1150 m), which yields a balance accumulation of 6 +/- 1 m ice a(-1).