Hypsometric control on glacier mass balance sensitivity in Alaska and northwest Canada
Hypsometric control on glacier mass balance sensitivity in Alaska and northwest Canada
复制标题
阿拉斯加和加拿大西北部冰川质量平衡敏感性的测压控制
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
E. W. Burgess
中科院分区：
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作者：
Daniel McGrath;L. Sass;Anthony A. Arendt;S. O’Neel;C. Kienholz;Christopher F. Larsen;E. W. Burgess
冰川测高提供了评估冰川对气候强迫响应的一级方法。我们将伦道夫冰川清单与一系列实地观测和气候模型输出相结合，以研究阿拉斯加和加拿大西北部约 27,000 座冰川到 21 世纪末的潜在变化。到 2100 年，根据代表性浓度路径 (RCP) 4.5–8.5 强迫，夏季气温预计将增加 +2.1 至 +4.6°C，而固体降水（雪）预计将减少 -6% 至 -11%，尽管总降水量增加 +9% 至 +21%。预计秋季降雪量将明显减少，积雪季节的开始时间将推迟约 1 个月。为了应对这些强迫，到 2100 年，区域平衡线高度 (ELA) 可能会增加 +105 至 +225 m。质量平衡对这种增加的敏感性变化很大，对海拔范围有限的冰川（通常是小型（<1 km2）冰川，占该地区冰川的 80%）或具有头重脚轻的几何形状的冰川影响最大，例如冰原。对于超过 20% 的冰川，在 RCP 6.0 强迫下，未来的 ELA 将超过冰川的最大海拔，导致其最终消亡，而对于其他冰川，积累面积比率将减少 > 60%。我们的结果强调了测高法对单个冰川对气候变化响应的一阶控制，以及测高法对一致气候扰动的区域响应引入的可变性。
Glacier hypsometry provides a first‐order approach for assessing a glacier's response to climate forcings. We couple the Randolph Glacier Inventory to a suite of in situ observations and climate model output to examine potential change for the ∼27,000 glaciers in Alaska and northwest Canada through the end of the 21st century. By 2100, based on Representative Concentration Pathways (RCPs) 4.5–8.5 forcings, summer temperatures are predicted to increase between +2.1 and +4.6°C, while solid precipitation (snow) is predicted to decrease by −6 to −11%, despite a +9 to +21% increase in total precipitation. Snow is predicted to undergo a pronounced decrease in the fall, shifting the start of the accumulation season back by ∼1 month. In response to these forcings, the regional equilibrium line altitude (ELA) may increase by +105 to +225 m by 2100. The mass balance sensitivity to this increase is highly variable, with the most substantive impact for glaciers with either limited elevation ranges (often small (<1 km2) glaciers, which account for 80% of glaciers in the region) or those with top‐heavy geometries, like icefields. For more than 20% of glaciers, future ELAs, given RCP 6.0 forcings, will exceed the maximum elevation of the glacier, resulting in their eventual demise, while for others, accumulation area ratios will decrease by >60%. Our results highlight the first‐order control of hypsometry on individual glacier response to climate change, and the variability that hypsometry introduces to a regional response to a coherent climate perturbation.