Hypsometry and sensitivity of the mass balance to changes in equilibrium-line altitude: the case of the Southern Patagonia Icefield
Hypsometry and sensitivity of the mass balance to changes in equilibrium-line altitude: the case of the Southern Patagonia Icefield
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DOI：
10.3189/2014jog13j127
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发表时间：
2014-01-01
影响因子：
3.4
通讯作者：
De Angelis, Hernan
中科院分区：
文献类型：
--
作者：
De Angelis, Hernan
我们研究了冰川测高和质量平衡率对平衡线高度（ELA）变化的敏感性之间的关系，以评估测高是否可以可靠地用于估计未测量的冰川对ELA变化的敏感性。我们表示的ELA，d（B）在dot/dELA的质量平衡率的敏感性，作为积累面积比（AAR）的函数，其对海拔的导数，dAAR/dELA，和ELA的质量平衡功能。然后，我们将这一概念应用到139个冰川在南巴塔哥尼亚冰原，我们得到的高度和AAR，并分析其质量平衡率敏感性的高度的影响。我们确认，大部分面积位于ELA以上（以下）的冰川是最不敏感的。冰川单峰的高度曲线的面积分数的峰值是目前的ELA，和冰川的双峰或多峰的面积分布，与ELA大约位于隆起之间，有中间的敏感性。我们的结论是，测高可以作为一个一阶估计的质量平衡率敏感性ELA的变化。
We study the relation between glacier hypsometry and sensitivity of mass-balance rate to changes in equilibrium-line altitude (ELA) to assess whether hypsometry can reliably be used to estimate the sensitivity of unmeasured glaciers to changes in ELA. We express the sensitivity of mass-balance rate to ELA, d(B) over dot/dELA, as a function of accumulation area ratio (AAR), its derivative against altitude, dAAR/dELA, and mass-balance functions of ELA. We then apply the concept to 139 glaciers in the Southern Patagonia Icefield for which we derive hypsometry and AAR, and analyze the influence of hypsometry on their mass-balance rate sensitivity. We confirm that glaciers where the bulk of area is located above (below) the ELA are the least (most) sensitive. Glaciers with unimodal hypsometric curves where the peak of area fraction is around the present ELA, and glaciers with bi- or multimodal area distributions, with the ELA located approximately between the bulges, have intermediate sensitivities. We conclude that hypsometry can be used as a first-order estimator of mass-balance rate sensitivity to ELA change.