GNSS uplift time series and ice surface elevation changes

We use Global Navigation Satellite System (GNSS) stations attached to bedrock to measure elastic displacements of the solid Earth caused by dynamic thinning near the glacier terminus. When we compare our results with discharge, we find a time lag between glacier speedup/slowdown and onset of dynamic thinning/thickening. Our results show that dynamic thinning/thickening on Jakobshavn Isbræ occurs 0.87 ± 0.07 years before speedup/slowdown. This implies that using GNSS time series we are able to predict speedup/slowdown of Jakobshavn Isbræ by up to 10.4 months. For Kangerlussuaq Glacier the lag between thinning/thickening and speedup/slowdown is 0.37 ± 0.17 years (4.4 months).

本研究利用安装于基岩的全球导航卫星系统（Global Navigation Satellite System, GNSS）台站，测量冰川末端附近动态减薄作用引发的固体地球弹性位移。将研究结果与冰川冰通量进行对比后发现，冰川速度的加速与减速过程，与动态减薄或增厚现象之间存在时间滞后。研究结果显示，雅各布港冰川（Jakobshavn Isbræ）的动态减薄/增厚发生于其速度变化（加速/减速）前0.87±0.07年。这表明，通过GNSS时间序列，我们最多可提前10.4个月预测雅各布港冰川的速度变化。对于康格鲁苏阿克冰川（Kangerlussuaq Glacier），其动态减薄/增厚与速度变化之间的滞后时长为0.37±0.17年（即4.4个月）。