Surface velocity fields of active rock glaciers and ice‐debris complexes in the Central Andes of Argentina
Surface velocity fields of active rock glaciers and ice‐debris complexes in the Central Andes of Argentina
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DOI：
10.1002/esp.5042
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发表时间：
2020-12
影响因子：
3.3
通讯作者：
J. Blöthe;Christian Halla;E. Schwalbe;E. Bottegal;Darío Trombotto Liaudat;L. Schrott
中科院分区：
文献类型：
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作者：
J. Blöthe;Christian Halla;E. Schwalbe;E. Bottegal;Darío Trombotto Liaudat;L. Schrott
岩石冰川和过渡冰碎屑复合体在安第斯山脉中部的地貌组合中占主导地位，但对其活动状态和运动学的区域研究仍然很少。在这里，我们利用阿根廷国家冰川清单来量化位于阿根廷普拉塔山脉的244个岩石冰川和51个冰碎片复合体的表面速度场。对2010年至2017/18年期间获得的RapidEye卫星图像应用特征跟踪方法，我们发现149个地貌的平均位移率在0.37至2.61 m年-1之间，而对于其余146个特征，地表移动仍然低于我们的检测水平。我们将我们的卫星导出的速度场与来自两个当地现场的地面实况数据进行了比较，并在震级和空间分布方面找到了密切匹配的结果。与其他山区相比，该地区三分之一的活跃岩石冰川和冰碎片复合体的平均位移超过1 m年-1，因此拥有数量异常多的快速流动冰缘地貌。使用随机森林模型，我们测试了25个形态和地形气候候选预测因子的预测能力，用于在两个不同尺度上模拟岩石冰川和冰碎屑复合体的活动状态。对于整个地形和个别地形段，沿沿着位移中心线，我们可以预测的活动状态，总体精度分别为70.08%（平均AUROC = 0.785）和74.86%（平均AUROC = 0.753）。虽然太阳辐射和海拔等地形气候参数对整个地貌最为重要，但几何参数在地貌段的尺度上变得更为重要。尽管尝试当地的斜率和表面运动学之间的相关性，我们的研究结果指出，整合的因素，斜率和距离的来源，以管理当地的变形。我们的结论是，光学图像中的功能跟踪是可行的，在偏远地区的区域研究，并提供了宝贵的洞察安第斯冰冻圈的现状。版权所有2020作者。出版社：John Wiley & Sons Ltd
Rock glaciers and transitional ice‐debris complexes predominate the Central Andean landform assemblage, yet regional studies on their state of activity and their kinematics remain sparse. Here we utilize the national glacier inventory of Argentina to quantify surface velocity fields of 244 rock glaciers and 51 ice‐debris complexes, located in the Cordón del Plata range, Argentina. Applying a feature‐tracking approach to repeated RapidEye satellite imagery acquired between 2010 and 2017/18, we find mean displacement rates between 0.37 and 2.61 m year−1 for 149 landforms, while for the remaining 146 features, surface movement remains below our level of detection. We compare our satellite‐derived velocity fields with ground‐truth data from two local field sites and find closely matching results in magnitude and spatial distribution. With average displacement of one‐third of the active rock glaciers and ice‐debris complexes exceeding 1 m year−1, the region hosts an exceptional number of fast‐flowing periglacial landforms, compared to other mountain belts. Using a random forest model, we test the predictive power of 25 morphometric and topoclimatic candidate predictors for modelling the state of activity of rock glaciers and ice‐debris complexes on two different scales. For entire landforms and individual landform segments, constructed along displacement centrelines, we can predict the state of activity with overall accuracies of 70.08% (mean AUROC = 0.785) and 74.86% (mean AUROC = 0.753), respectively. While topoclimatic parameters such as solar radiation and elevation are most important for entire landforms, geometric parameters become more important at the scale of landform segments. Despite tentative correlations between local slope and surface kinematics, our results point to factors integrating slope and distance to the source to govern local deformation. We conclude that feature tracking in optical imagery is feasible for regional studies in remote regions and provides valuable insight into the current state of the Andean cryosphere. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd