Glacier runoff variations since 1955 in the Maipo River basin, in the semiarid Andes of central Chile
Glacier runoff variations since 1955 in the Maipo River basin, in the semiarid Andes of central Chile
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DOI：
10.5194/tc-14-2005-2020
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发表时间：
2020-06-24
期刊：
影响因子：
5.2
通讯作者：
Farinotti, Daniel
中科院分区：
文献类型：
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作者：
Ayala, Alvaro;Farias-Barahona, David;Farinotti, Daniel
随着冰川根据气候变化调整其大小，预计融水产量会发生长期变化，从而影响当地水资源的可用性。我们调查了 1955 年至 2016 年期间智利半干旱安第斯山脉迈坡河流域（4843 km(2)，南纬 33.0-34.3 度，西经 69.8-70.5 度）的冰川径流。流域内有800多条冰川，总面积378km(2)（2000年清查）。我们使用物理导向和完全分布的 TOPKAPI（地形运动学近似和积分）-ETH 冰川水文模型对 26 个冰川的质量平衡和径流贡献进行建模，并将结果外推到整个流域。 TOPKAPI-ETH 使用多个冰川和气象数据集按每日时间步长运行，并根据 1955-2000 年和 2000-2013 年期间的水流记录、遥感积雪和大地质量平衡对其结果进行评估。结果表明，1955-2016年冰川质量平衡总体呈流域平均下降趋势，但各主要流域之间也存在差异。冰川体积减少了五分之一（从 18.6 +/- 4.5 减少到 14.9 +/- 2.9 km(3)）。最初冰川化地区的径流为 177 +/- 25 mm yr(-1)（占盆地总贡献的 16 +/- 7%），但它显示出最大值的递减序列，这可能与 1980 年代以来降水量减少和冰融化减少之间的相互作用有关。麦坡河流域的冰川将继续消退，因为它们与当前的气候不平衡。在假设的恒定气候情景下，冰川体积将减少至 2000 年体积的 81 +/- 38%，冰川径流将是 1955-2016 年平均值的 78 +/- 30%。这将大大降低流域的抗旱能力。
As glaciers adjust their size in response to climate variations, long-term changes in meltwater production can be expected, affecting the local availability of water resources. We investigate glacier runoff in the period 1955-2016 in the Maipo River basin (4843 km(2), 33.0-34.3 degrees S, 69.8-70.5 degrees W), in the semiarid Andes of Chile. The basin contains more than 800 glaciers, which cover 378 km(2) in total (inventoried in 2000). We model the mass balance and runoff contribution of 26 glaciers with the physically oriented and fully distributed TOPKAPI (Topographic Kinematic Approximation and Integration)-ETH glacio-hydrological model and extrapolate the results to the entire basin. TOPKAPI-ETH is run at a daily time step using several glaciological and meteorological datasets, and its results are evaluated against streamflow records, remotely sensed snow cover, and geodetic mass balances for the periods 1955-2000 and 2000-2013. Results show that in 1955-2016 glacier mass balance had a general decreasing trend as a basin average but also had differences between the main sub-catchments. Glacier volume decreased by one-fifth (from 18.6 +/- 4.5 to 14.9 +/- 2.9 km(3)). Runoff from the initially glacierized areas was 177 +/- 25 mm yr(-1) (16 +/- 7 % of the total contributions to the basin), but it shows a decreasing sequence of maxima, which can be linked to the interplay between a decrease in precipitation since the 1980s and the reduction of ice melt. Glaciers in the Maipo River basin will continue retreating because they are not in equilibrium with the current climate. In a hypothetical constant climate scenario, glacier volume would reduce to 81 +/- 38 % of the year 2000 volume, and glacier runoff would be 78 +/- 30 % of the 1955-2016 average. This would considerably decrease the drought mitigation capacity of the basin.