Antarctic-wide annual ice flow maps from Landsat 8 imagery between 2013 and 2019

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.冰流速是量化冰盖物质输出速率的核心参数，对于优化南极冰盖耦合模型、精准预测其对未来全球海平面上升的贡献至关重要。然而在南极地区，高分辨率且连续的冰流速估算仍难以获取，而这正是揭示当前南极冰质量平衡过程的关键所在。本研究发布了一套基于陆地卫星8号（Landsat 8）光学影像数据生成的南极全域年度采样冰流速产品，其网格间距为105米。我们首先详述了一套可自动校准并整合冰位移图以生成南极全域无缝冰流速产品的流程。该年度冰流速镶嵌图总计使用25万张冰位移图，这些位移图由2013年12月至2019年4月间获取的8万余幅陆地卫星8号影像推算得到。相较于现有数据产品，这款全新的南极年度冰流速数据产品实现了近十年尺度南极全域冰流的更精准量化，同时为更高空间分辨率与年度采样尺度下的冰动力学研究提供了新的契机。验证研究证实，与独立估算的光学与雷达冰流速数据产品以及原位观测数据相比，该新型数据产品的精度与一致性均得到了显著提升。