Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR
Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR
复制标题
DOI：
10.5194/tc-7-1109-2013
复制
发表时间：
2013-07
期刊：
影响因子：
--
通讯作者：
Lin Liu;C. Millar;R. Westfall;H. Zebker
中科院分区：
文献类型：
--
作者：
Lin Liu;C. Millar;R. Westfall;H. Zebker
抽象的。尽管美国加利福尼亚州内华达山脉有丰富的岩石冰川，但人们很少努力测量其表面流量。在这里，我们使用干涉合成孔径雷达（InSAR）技术编制了描述该地区 59 个活动岩石冰川运动状态的基准清单。 2007 年夏末，这些岩石冰川的移动速度从 14 cm yr−1 到 87 cm yr−1 不等，区域平均值为 53 cm yr−1。我们的清单揭示了空间差异：内华达山脉南部的岩石冰川比内华达山脉中部的岩石冰川移动得更快。除了区域测绘外，我们还进行了一项案例研究，以精细的空间和时间细节测量吉布斯山岩石冰川的表面流量。该目标的 InSAR 测量结果表明：(1) 气流的空间格局与地表地貌特征相关；(2) 气流速度存在显着的季节性变化，2007 年秋季的峰值为 48 cm yr−1，是 2008 年春季观测到的最小值的两倍多。季节性变化比气温滞后三个月。我们对表面速度季节性变化的发现强化了具有高时间采样率的长时间序列的重要性，以检测气候变暖中岩石冰川运动学可能的长期变化。
Abstract. Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. In the late summer of 2007, these rock glaciers moved at speeds that range from 14 cm yr−1 to 87 cm yr−1, with a regional mean value of 53 cm yr−1. Our inventory reveals a spatial difference: rock glaciers in the southern Sierra Nevada moved faster than the ones in the central Sierra Nevada. In addition to the regional mapping, we also conduct a case study to measure the surface flow of the Mount Gibbs rock glacier in fine spatial and temporal detail. The InSAR measurements over this target reveal (1) that the spatial pattern of flow is correlated with surface geomorphic features and (2) a significant seasonal variation of flow speed whose peak value was 48 cm yr−1in the fall of 2007, more than twice the minimum value observed in the spring of 2008. The seasonal variation lagged air temperatures by three months. Our finding on the seasonal variation of surface speed reinforces the importance of a long time series with high temporal sampling rates to detect possible long-term changes of rock glacier kinematics in a warming climate.