South American Andes elevation changes from 2000 to 2018, links to GeoTIFFs

Glaciers in the Andes are among the fastest shrinking and largest contributors to sea level rise in the world. They also represent crucial water resources in many tropical and semi-arid portions of this extensive mountain range. Yet, the magnitude of the recent ice loss over the entire Andes cordillera is still debated. Here we present Andean glacier mass changes (from 10°N to 56°S) between 2000 and 2018 using time series of digital elevation models derived from ASTER stereo images. The total mass change is -22.9 ± 5.9 Gt yr-1 (-0.72 ± 0.22 m w.e. yr-1), with the most negative mass balances in the Patagonic Andes (-0.78 ± 0.25 m w.e. yr-1) and the Tropical Andes (-0.42 ± 0.24 m w.e. yr-1), and relatively moderate losses (-0.28 ± 0.18 m w.e. yr-1) in the Dry Andes. Sub-period analysis (2000-2009 vs. 2009-2018) reveals steady mass loss in the Tropics and south of 45°S. Conversely, a shift from slightly positive to strongly negative mass balance is measured between 26° and 45°S. In this latter region, the rapid glacier loss in recent years coincides with extremely dry conditions since 2010 and partially helped to mitigate the negative hydrological impacts of this severe drought. These results provide a comprehensive, high resolution and multi-decadal dataset of recent Andes-wide glacier mass changes that constitutes a relevant basis for calibration and validation of hydrological and glaciological models intended to project future glacier changes and their hydrological impacts.

安第斯山脉的冰川是全球退缩速度最快的冰川类群之一，同时也是全球海平面上升的主要贡献源之一。它们亦是这条广袤山系中众多热带及半干旱区域的核心水资源储备。然而，整个安第斯科迪勒拉山系（Andes cordillera）近期的冰量损失规模仍存在学术争议。本研究利用由ASTER立体影像（ASTER stereo images）衍生得到的数字高程模型（digital elevation models）时间序列，构建了2000年至2018年间北纬10°至南纬56°范围内的安第斯冰川质量变化数据集。研究得到的总质量变化为-22.9±5.9吉吨/年（-0.72±0.22米水当量/年，其中w.e.为水当量（water equivalent））；其中巴塔哥尼亚安第斯山脉的质量平衡亏损最为显著（-0.78±0.25米水当量/年），热带安第斯山脉次之（-0.42±0.24米水当量/年），干旱安第斯山脉的冰川损失相对平缓（-0.28±0.18米水当量/年）。分时段对比分析（2000-2009年与2009-2018年）显示，热带安第斯山脉及南纬45°以南区域的冰量损失呈稳定态势。与之相反，南纬26°至45°区间的冰川质量平衡则呈现出从微弱正向转为强烈负向的显著转变。在该区域内，近年的快速冰川消融与2010年以来的极端干旱气候相契合，且冰川消融在一定程度上缓解了此次严重干旱带来的负面水文影响。本研究成果提供了一套覆盖全安第斯山脉、高分辨率且多十年尺度的冰川质量变化综合数据集，可为用于预测未来冰川变化及其水文影响的水文与冰川学模型的率定与验证提供重要依据。