ABSTRACT

Ice velocity constitutes a key parameter for quantifying ice-sheet discharge rates and is thus crucial for improving the coupled models of the Antarctic ice sheet towards accurately predict its contribution to future global sea-level rise. However, in Antarctica, high-resolution and continuous ice velocity estimates remain elusive, which is key to unravel Antarctica’s present-day ice mass balance processes. Here, we present a suite of newly estimated Antarctic-wide, annually-sampled ice velocity products at 105-m grid-spacing observed by Landsat 8 optical images data. We first describe a procedure that can automatically calibrate and integrate ice displacement maps to generate Antarctic-wide seamless ice velocity products. The annual ice velocity mosaics are assembled using a total of 250,000 displacement maps inferred from more than 80,000 Landsat 8 images acquired between December 2013 and April 2019. The new annual Antarctic ice velocity data product exhibits an improved quantification of near-decadal Antarctic-wide ice flow, and an opportunity to investigate ice dynamics at a higher spatial resolution and annual sampling, as compared to existing data products. Validation studies confirmed improved accuracy and consistency of this new data product, when compared with independently estimated optical and radar ice velocity data products, as well as in situ data.

摘要

冰速是量化冰盖排放速率的关键参数，因此对于改进南极冰盖的耦合模型，准确预测其对未来全球海平面上升的贡献至关重要。但是，在南极洲，高分辨率和连续的冰速估算仍然难以捉摸，这对于弄清南极洲目前的冰质平衡过程至关重要。在这里，我们展示了一套由Landsat 8光学图像数据观测到的，新估计的，在南极范围内，每年采样的冰速度产品的105米网格间距的套件。我们首先描述一个程序，该程序可以自动校准和整合冰位移图以生成南极范围内的无缝冰速积。每年的冰速镶嵌图是根据从80多个，在2013年12月至2019年4月之间获取了000张Landsat 8图像。新的南极年度冰速度数据产品展示了近十年的南极全冰流动的量化，并提供了以更高的空间分辨率和年度采样研究冰动力学的机会，与现有数据产品相比 验证研究证实，与独立估算的光学和雷达冰速数据产品以及原位数据。