Seasonal evolution of supraglacial lake volume from ASTER imagery
Seasonal evolution of supraglacial lake volume from ASTER imagery
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DOI：
10.3189/172756409789624328
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发表时间：
2009-10
影响因子：
2.9
通讯作者：
S. Georgiou;Andrew Shepherd;M. McMillan;P. Nienow
中科院分区：
文献类型：
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作者：
S. Georgiou;Andrew Shepherd;M. McMillan;P. Nienow
在考虑格陵兰冰盖的季节性和长期演变时，冰上湖泊的储水量和释放水量是一个重要因素。本文利用辐射传输模型估算了2002 - 2005年间西格陵兰Jakobshavn Isbræ表层冰上湖的深度和体积变化。与机载激光雷达观测确定的湖泊深度估计值相比，我们估计在无云条件下，模拟湖泊深度的均方根偏差为0.3 m。最大湖泊面积为3.4 km2，深度为9.6±1.0 m，体积为（18.6±3.7）×106 m3。当根据每张图像之前累积的正度日数（pdd）进行排序时，我们观察到湖泊体积的演变分为三个不同的阶段。在融化季节开始时，填充速度较慢；潜水泵在大约80个潜水泵后，潜水泵的充注速度增加了一倍，潜水泵在大约125个潜水泵后，潜水泵迅速排水。我们估计，在6天的时间内，湖泊的排水速度最低为（2.66±0.53）×106 m3 d-1。
Abstract Water stored in and released from supraglacial lakes is an important factor when considering the seasonal and long-term evolution of the Greenland ice sheet. Here we use a radiative transfer model to estimate changes in the depth and volume of a supraglacial lake on the surface of Jakobshavn Isbræ, West Greenland, between 2002 and 2005. When compared to estimates of the lake depth determined from airborne lidar observations, we estimate that the root-mean-square departure of the modelled lake depths was 0.3 m during cloud-free conditions. The maximum lake area, depth and volume were 3.4 km2, 9.6 ±1.0 m and (18.6±3.7)×106 m3, respectively. When sequenced according to the number of positive degree-days (PDDs) accumulated prior to each image, we observe that the lake volume evolves in three distinct phases. At the start of the melting season, the rate of filling is slow; after approximately 80 PDDs the rate of filling increases by a factor ∽3, and after approximately 125 PDDs the lake drains rapidly. We estimate that the lake drains at a minimum rate of (2.66±0.53)×106 m3 d–1 over a 6 day period.