Six Decades of Glacial Mass Loss in the Canadian Arctic Archipelago
Six Decades of Glacial Mass Loss in the Canadian Arctic Archipelago
复制标题
加拿大北极群岛六年的冰川质量损失
DOI：
10.1029/2017jf004304
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
M. R. van den Broeke
中科院分区：
文献类型：
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作者：
A. Cook;L. Copland;B. Noël;C. Stokes;M. J. Bentley;M. Sharp;R. Bingham;M. R. van den Broeke
加拿大北极群岛由多个小冰川和冰帽组成，主要集中在群岛北部（NCAA，加拿大北部北极群岛）和南部（SCAA，加拿大南部北极群岛）的埃尔斯米尔和巴芬群岛。由于这些冰川很小且几何形状复杂，目前使用5 - 20公里水平分辨率的区域气候模式不能正确地解析地表物质平衡模式。在这里，我们展示了加拿大北极群岛58年（1958-2015）的日地表物质平衡重建，统计上从区域气候模式RACMO2.3输出的11公里缩小到1公里。通过校正海拔和冰反照率的偏差，降尺度方法显著改善了窄出口冰川和孤立冰原的径流估算。近20年来，NCAA和SCAA冰川经历了变暖（+1.1°C），导致质量损失持续增加，分别为28.2±11.5和22.0±4.5 Gt/年，分别是1996年之前平均值的两倍（11.9 Gt/年）和两倍（11.9 Gt/年）。虽然NCAA冰盖的内部仍然可以缓冲大部分额外的融化，但自20世纪80年代以来，在低洼的SCAA冰川上缺乏常年的冰冻区已经造成了不间断的质量损失。在缺乏显著的再冻结能力的情况下，这表明这些高度敏感的冰川不可避免地会消失。
The Canadian Arctic Archipelago comprises multiple small glaciers and ice caps, mostly concentrated on Ellesmere and Baffin Islands in the northern (NCAA, Northern Canadian Arctic Archipelago) and southern parts (SCAA, Southern Canadian Arctic Archipelago) of the archipelago, respectively. Because these glaciers are small and show complex geometries, current regional climate models, using 5‐ to 20‐km horizontal resolution, do not properly resolve surface mass balance patterns. Here we present a 58‐year (1958–2015) reconstruction of daily surface mass balance of the Canadian Arctic Archipelago, statistically downscaled to 1 km from the output of the regional climate model RACMO2.3 at 11 km. By correcting for biases in elevation and ice albedo, the downscaling method significantly improves runoff estimates over narrow outlet glaciers and isolated ice fields. Since the last two decades, NCAA and SCAA glaciers have experienced warmer conditions (+1.1°C) resulting in continued mass loss of 28.2 ± 11.5 and 22.0 ± 4.5 Gt/year, respectively, more than doubling (11.9 Gt/year) and doubling (11.9 Gt/year) the pre‐1996 average. While the interior of NCAA ice caps can still buffer most of the additional melt, the lack of a perennial firn area over low‐lying SCAA glaciers has caused uninterrupted mass loss since the 1980s. In the absence of significant refreezing capacity, this indicates inevitable disappearance of these highly sensitive glaciers.