Characterizing interannual variability of glacier dynamics and dynamic discharge (1999–2015) for the ice masses of Ellesmere and Axel Heiberg Islands, Nunavut, Canada
Characterizing interannual variability of glacier dynamics and dynamic discharge (1999–2015) for the ice masses of Ellesmere and Axel Heiberg Islands, Nunavut, Canada
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加拿大努纳武特地区埃尔斯米尔和阿克塞尔海伯格群岛冰块的冰川动力学和动态流量（1999-2015）的年际变化特征
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发表时间：
2016
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通讯作者：
C. Mortimer
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作者：
W. Van Wychen;Jamie Davis;D. Burgess;L. Copland;L. Gray;M. Sharp;C. Mortimer
Landsat 7和RADARSAT-1/RADARSAT-2卫星图像被用来制作迄今为止加拿大北极高地冰川运动的最全面记录，并描述过去约15年来冰流的空间和时间变化。这使我们能够评估动态驱动的冰川变化是否可以归因于“涌动”或“脉冲”，或者是否涉及其他机制。通过雷达速度测绘，可以计算2000年和2011-2015年期间的年度区域动态流量（冰山崩解）（得出的平均区域流量为2.21 ± 0.68 Gt a−1），通过光学图像特征跟踪得出的速度可以计算1999 - 2010年选定冰川的年度动态流量。自2011年以来，该地区的几个主要的终止冰川已经减速，其动态流量已经减少。Trinity和Wykeham Glaciers（威尔士王子冰原）代表了与这种模式的显著偏离，因为它们在研究期间普遍加速。由此产生的增加，从这些冰川的动态放电完全补偿（误差范围内）的减少，从整个研究区域的其他tiblion冰川放电。这两个冰川占2015年冬季区域动态流量的约62%（2000年为约22%），表明加拿大高北极地区的总冰流量可能对少数几个冰川流量的变化敏感。
Landsat 7 and RADARSAT‐1/RADARSAT‐2 satellite images are used to produce the most comprehensive record of glacier motion in the Canadian High Arctic to date and to characterize spatial and temporal variability in ice flow over the past ~15 years. This allows us to assess whether dynamically driven glacier change can be attributed to “surging” or “pulsing,” or whether other mechanisms are involved. RADAR velocity mapping allows annual regional dynamic discharge (iceberg calving) to be calculated for 2000 and the period 2011–2015 (yielding a mean regional discharge of 2.21 ± 0.68 Gt a−1), and velocities derived from feature tracking of optical imagery allow for annual dynamic discharge to be calculated for select glaciers from 1999 to 2010. Since ~2011, several of the major tidewater‐terminating glaciers within the region have decelerated and their dynamic discharge has decreased. Trinity and Wykeham Glaciers (Prince of Wales Icefield) represent a notable departure from this pattern as they have generally accelerated over the study period. The resulting increase in dynamic discharge from these glaciers entirely compensates (within error limits) for the decrease in discharge from the other tidewater glaciers across the study region. These two glaciers accounted for ~62% of total regional dynamic discharge in winter 2015 (compared to ~22% in 2000), demonstrating that total ice discharge from the Canadian High Arctic can be sensitive to variations in flow of just a few tidewater glaciers.