Recent elevation changes of Svalbard glaciers derived from ICESat laser altimetry
Recent elevation changes of Svalbard glaciers derived from ICESat laser altimetry
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DOI：
10.1016/j.rse.2010.06.008
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发表时间：
2010-11-15
影响因子：
13.5
通讯作者：
Kohler, Jack
中科院分区：
文献类型：
--
作者：
Moholdt, Geir;Nuth, Christopher;Kohler, Jack
我们测试了三种通过多时相 ICESat 激光测高估计斯瓦尔巴冰川 2003-2008 年海拔变化的方法：(a) 上升和下降轨迹之间交叉点的线性插值，(b) 使用数字高程模型 (DEM) 将近重复轨迹投影到常见位置，以及 (c) 假设海拔变化率恒定，将刚性平面与重复轨迹数据段进行最小二乘拟合。这两种重复跟踪方法产生相似的结果，并且与更准确但稀疏采样的交叉点相比效果很好。 2003年至2008年间，斯瓦尔巴群岛的大部分冰川区域经历了低海拔冰川减薄和高海拔平衡或增厚的过程。斯瓦尔巴群岛 34,600 km(2) 冰川的大地测量质量平衡（不包括崩解前沿后退或前进）估计为 -4.3 +/- 1.4 Gt y(-1)，对应于 -0.12 +/- 0.04 m w.e. 的区域平均水当量 (we.) 平衡。 y(-1)。最大的冰损失发生在西部和南部，而斯匹次卑尔根岛东北部和奥斯特丰纳冰盖的面积却增加了。采用相同方法得出的冬季和夏季海拔变化表明，物质平衡的空间梯度主要是由于夏季西部和南部的稀疏程度大于东北部。我们的研究结果与同一时期的现场质量平衡测量结果一致，证实重复跟踪卫星测高可以成为监测北极冰川短期海拔变化的宝贵工具。 (C) 2010 Elsevier Inc. 保留所有权利。
We have tested three methods for estimating 2003-2008 elevation changes of Svalbard glaciers from multi-temporal ICESat laser altimetry: (a) linear interpolation of crossover points between ascending and descending tracks, (b) projection of near repeat-tracks onto common locations using Digital Elevation Models (DEMs), and (c) least-squares fitting of rigid planes to segments of repeat-track data assuming a constant elevation change rate. The two repeat-track methods yield similar results and compare well to the more accurate, but sparsely sampled, crossover points. Most glacier regions in Svalbard have experienced low-elevation thinning combined with high-elevation balance or thickening during 2003-2008. The geodetic mass balance (excluding calving front retreat or advance) of Svalbard's 34,600 km(2) glaciers is estimated to be -4.3 +/- 1.4 Gt y(-1), corresponding to an area-averaged water equivalent (we.) balance of -0.12 +/- 0.04 m w.e. y(-1). The largest ice losses have occurred in the west and south, while northeastern Spitsbergen and the Austfonna ice cap have gained mass. Winter and summer elevation changes derived from the same methods indicate that the spatial gradient in mass balance is mainly due to a larger summer season thinning in the west and the south than in the northeast. Our findings are consistent with in-situ mass balance measurements from the same period, confirming that repeat-track satellite altimetry can be a valuable tool for monitoring short term elevation changes of Arctic glaciers. (C) 2010 Elsevier Inc. All rights reserved.