基于Sentinel-1 SAR数据的南极松岛冰川流速监测

Flow velocity of the Pine Island Glacier, West Antarctica, derived from Sentinel-1 SAR data

南极入海冰川的流速对了解物质平衡和海平面上升具有重要意义。基于Sentinel-1 SAR数据,利用特征跟踪法提取了2015-2017年松岛冰川的冬夏季流速,分析了冰川流速的年际和季节变化特征。结果表明松岛冰川处于高速流动状态,流速最高达4 400 m·a^(-1)左右。沿主流线方向, 2015-2017年2月(夏季)的平均流速分别是3 502 m·a^(-1)、 3 529 m·a^(-1)、 3 498 m·a^(-1)。2015-2017年8月(冬季)的平均流速分别是3 473 m·a^(-1)、 3 498 m·a^(-1)、 3 478 m·a^(-1)。2015-2017年松岛冰川主流线上平均流速为3 450～3 550 m·a^(-1),流速总体保持稳定,没有明显变化。2015-2017年松岛冰川流速没有明显季节差异,冬夏季流速大致持平。基于裸露岩石作为控制点的分析表明误差为22～39 m·a^(-1),冰川流速监测结果是可信的。

The flow velocity of outlet glaciers in Antarctica is of great significance for understanding mass balance and sea level rise. Based on the Sentinel-1 SAR data, the flow velocity of Pine Island Glacier in West Antarctica from 2015 to 2017 was extracted by using the feature-tracking method;the annual and seasonal variations of the velocity were analyzed. The results showed that the Pine Island Glacier had flowed at a high-speed, with a maximum velocity up to 4 400 m·a-1. Along the mainstream line AB, the average velocity in February(summer) of 2015-2017 were 3 502 m·a-1, 3 529 m·a-1 and 3 498 m·a-1, respectively. The average velocity in August(winter) of 2015-2017 were 3 473 m·a-1, 3 498 m·a-1 and 3 478 m·a-1, respectively. All the average velocities were between 3 450~3 550 m·a-1, with less fluctuation from 2015 to 2017. Also there was no obvious seasonal variation of flow velocity in 2015-2017, and almost the same in summer and in winter. The error analysis based on bare rock as control point shows that the velocity error margin ranges between 22~39 m·a-1, thus the extracted glacier flow velocities is credible.