Surge dynamics in the Nathorstbreen glacier system, Svalbard
Surge dynamics in the Nathorstbreen glacier system, Svalbard
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DOI：
10.5194/tc-8-623-2014
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发表时间：
2013-10
期刊：
影响因子：
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通讯作者：
M. Sund;M. Sund;T. R. Lauknes;T. Eiken
中科院分区：
文献类型：
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作者：
M. Sund;M. Sund;T. R. Lauknes;T. Eiken
抽象的。Nathorstbreen冰川系统（NGS）最近经历了自1936年以来斯瓦尔巴群岛最大的激增，这是检查使用空间和时间观测DEM差分，时间序列的表面速度从卫星合成孔径雷达（SAR）和其他来源。上部盆地最大的积累在平静对应的地区的初始降低。初始加速超过静态速度几十倍。这表明，多温冰川浪涌开始在温带地区之前，质量被转移到冰川。随后的下冰川物质位移与冰川速度增加100-200倍的地区相吻合（第2阶段）。经过5年多的时间，联合NGS终点站在冬季突然进入峡湾，甚至增加了速度。推进之后，裂缝向冰川上方扩展，这表明冰川中部以及随后的上部对大规模位移做出了反应。NGS前进了约15公里，而由于产犊，又损失了约3公里的长度。在一些冰川上游地区观察到约50 m的表面下降，5年内冰川总面积增加了20%。测得的最大流速至少为25 m d−1，是静态流速的2500倍，而平均流速约为10 m d−1。Zawadzkibreen周期的浪涌与ca。70-年期间。
Abstract. Nathorstbreen glacier system (NGS) recently experienced the largest surge in Svalbard since 1936, and this was examined using spatial and temporal observations from DEM differencing, time series of surface velocities from satellite synthetic aperture radar (SAR) and other sources. The upper basins with maximum accumulation during quiescence corresponded to regions of initial lowering. Initial speed-up exceeded quiescent velocities by a factor of several tens. This suggests that polythermal glacier surges are initiated in the temperate area before mass is displaced downglacier. Subsequent downglacier mass displacement coincided with areas where glacier velocity increased by a factor of 100–200 times (stage 2). After more than 5 years, the joint NGS terminus advanced abruptly into the fjord during winter, increasing velocities even more. The advance was followed by up-glacier propagation of crevasses, indicating the middle and subsequently the upper part of the glaciers reacting to the mass displacement. NGS advanced ~15 km, while another ~3 km length was lost due to calving. Surface lowering of ~50 m was observed in some up-glacier areas, and in 5 years the total glacier area increased by 20%. Maximum measured flow rates were at least 25 m d−1, 2500 times quiescent velocity, while average velocities were about 10 m d−1. The surges of Zawadzkibreen cycle with ca. 70-year periods.