A surge of Perseibreen, Svalbard, examined using aerial photography and ASTER high resolution satellite imagery
A surge of Perseibreen, Svalbard, examined using aerial photography and ASTER high resolution satellite imagery
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DOI：
10.3402/polar.v22i2.6466
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发表时间：
2003-01
期刊：
影响因子：
1.9
通讯作者：
J. Dowdeswell;T. Benham
中科院分区：
文献类型：
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作者：
J. Dowdeswell;T. Benham
确定浪涌活动对于评估斯瓦尔巴冰川浪涌周期的活跃期和静止期的持续时间很重要。卫星和航空摄影图像用于识别和描述位于斯匹次卑尔根岛东海岸的59平方公里的山谷冰川Perseibreen的形态和流动。2002年4月，在英仙座上首次观测到地表裂缝和陡峭的冰锋，这表明了涌浪活动。对高分辨率（15米）先进星载热发射和反射辐射计（ASTER）卫星图像的检查证实了这种浪涌活动。1961年至1990年间，佩尔塞布林后退了近750米。从1990年到2000年夏天，Perseibreen从撤退转向前进。2000年6月至2001年5月期间，气候变化呈快速推进趋势，终末年推进量超过400米。在2001年5月至8月期间，这一比率增加到每年7.5亿以上。观察到的裂缝方向表明冰处于纵向张力状态，表明质量向冰川下转移。2001年5月至8月间，根据ASTER图像之间的图像相关性得出的冰表面速度为2-2.5 m d-1。冰川以相对均匀的速度流动，靠近其侧缘处有陡峭的速度梯度，这是涌浪周期活跃期冰块典型的速度结构。应力状态自始至终都是外延的，涌动似乎是从冰川的低处开始的。这与其他斯瓦尔巴群岛潮汐冰川的活动期动力学相似。Perseibreen可能至少从1870年开始就不活跃了，到现在的高潮大约有130年的时间，这定义了静止阶段的最小长度。
The identification of surge activity is important in assessing the duration of the active and quiescent phases of the surge cycle of Svalbard glaciers. Satellite and aerial photographic images are used to identify and describe the form and flow of Perseibreen, a valley glacier of 59 km2 on the east coast of Spitsbergen. Heavy surface crevassing and a steep ice front, indicative of surge activity, were first observed on Perseibreen in April 2002. Examination of high resolution (15 m) Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite imagery confirmed this surge activity. Perseibreen retreated by almost 750 m between 1961 and 1990. Between 1990 and the summer of 2000, Perseibreen switched from retreat and its front began to advance. Rapid advance was underway during the period June 2000 to May 2001, with terminus advance at over 400 m yr-1. Between May and August 2001 the rate increased to over 750 m yr-1. The observed crevasse orientation indicates that ice was in longitudinal tension, suggesting the down-glacier transfer of mass. Ice surface velocities, derived from image correlation between ASTER images, were 2-2.5 m d-1 between May and August 2001. The glacier was flowing at a relatively uniform speed with sharp velocity gradients located close to its lateral margins, a velocity structure typical of ice masses in the active phase of the surge cycle. The stress regime is extensional throughout and the surge appears to be initiated low on the glacier. This is similar to the active-phase dynamics of other Svalbard tidewater glaciers. Perseibreen has probably been inactive since at least 1870, a period of about 130 years to the present surge which defines a minimum length for the quiescent phase.