Influence of recent warming and ice dynamics on glacier surface elevations in the Canadian High Arctic, 1995–2014
Influence of recent warming and ice dynamics on glacier surface elevations in the Canadian High Arctic, 1995–2014
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1995-2014 年近期变暖和冰动态对加拿大高北极冰川表面海拔的影响
DOI：
10.1017/jog.2018.37
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发表时间：
2018
影响因子：
3.4
通讯作者：
W. Van Wychen
中科院分区：
文献类型：
--
作者：
C. Mortimer;M. Sharp;W. Van Wychen
重复的机载激光测高测量显示，自1995年以来，加拿大伊丽莎白女王群岛的冰川普遍变薄（表面降低）。在2005/06年至2012/14年五季期间，50米海拔箱的平均稀疏率比前两个五季高出三倍以上。相对于1995-2012/14年的平均值，2005/06 - 2012/14年的厚度变化（dh/dt）呈强烈的负异常，这表明大多数测得的减薄发生在最近5-6年期间，当时平均夏季地表温度（LSTs）非常高，平均夏季黑天短波宽带反射率（BSA）非常低，相对于2000/01-15/16期间，高空（700 hPa）和近地面（2 m）气温比1995-2012年平均值高0.8°C至1.5°C。比较dh/dt平均夏季LST和BSA测量的中分辨率成像光谱仪和表面纵向应变率计算的表面速度场来自雷达卫星1/2和Landat-7 ETM +数据表明，表面海拔变化主要是由气候变化驱动的。一个例外发生在沿着许多快速流动的出口冰川，冰的动态似乎也发挥了重要作用，在表面海拔变化。
ABSTRACT Repeat airborne laser altimetry measurements show widespread thinning (surface lowering) of glaciers in Canada's Queen Elizabeth Islands since 1995. Thinning rates averaged for 50 m elevation bins, were more than three times higher during the period 2005/06 to 2012/14 pentad than during the previous two pentads. Strongly negative thickness change (dh/dt) anomalies from 2005/06 to 2012/14, relative to the 1995–2012/14 mean, suggest that most of the measured thinning occurred during the most recent 5–6 year period when mean summer land surface temperatures (LSTs) were anomalously high and the mean summer black-sky shortwave broadband albedos (BSA) were anomalously low, relative to the 2000/01–15/16 period, and upper-air (700 hPa) and near surface (2 m) air temperatures were between 0.8°C and 1.5°C higher than 1995–2012 mean. Comparisons of dh/dt with mean summer LST and BSA measurements from the Moderate Resolution Imaging Spectroradiometer and with surface longitudinal strain rates computed from surface velocity fields derived from RADARSAT 1/2 and Landat-7 ETM + data suggest that surface elevation changes were driven mainly by changes in climate. An exception to this occurs along many fast-flowing outlet glaciers where ice dynamics appear also to have played an important role in surface elevation changes.