Elevation changes of ice caps in the Canadian Arctic Archipelago
Elevation changes of ice caps in the Canadian Arctic Archipelago
复制标题
加拿大北极群岛冰盖海拔变化
DOI：
10.1029/2003jf000045
复制
发表时间：
2004
影响因子：
--
通讯作者：
R. Koerner
中科院分区：
文献类型：
--
作者：
W. Abdalati;W. Krabill;E. Frederick;S. Manizade;C. Martin;J. Sonntag;R. Swift;R. Thomas;J. Yungel;R. Koerner
[1]1995年和2000年春季，对加拿大北极群岛的主要冰盖进行了精确的重复航空激光测量，以测量该区域的海拔变化。我们的测量显示，大多数冰盖和冰川在较低海拔(1600米以下)变薄，但在冰盖堆积区，变化很小，或在较高海拔变厚。最近该地区降水量的增加可以解释观测到的地方略有增厚，但不能解释低海拔地区的变薄。伊丽莎白女王群岛北部冰盖的减薄幅度一般为0.5m；yr−1，这与该地区在两次调查之间的5年期间气温异常的预期是一致的，似乎是始于1980年代中期的趋势的延续。然而，再往南一点，在巴芬岛的巴恩斯和彭尼冰帽上，这种变薄在较低海拔的−1超过1米时更加明显。这里的温度异常非常小，在低海拔地区变薄的程度远远超过任何相关的增强消融。对巴恩斯，或许还有佩妮的观察，与之前对巴恩斯冰盖提出的观点一致，即观察到的冰川变薄是更长期冰川消融的一部分。根据我们的数据中海拔和海拔变化之间的区域关系，1995年至2000年该群岛的物质平衡估计为−25km3yr−1，相当于海平面上升0.064 mm yr−1。这使它成为最重要的海平面上升来源之一，尽管不如格陵兰冰盖、阿拉斯加冰川或巴塔哥尼亚冰原那么大。
[1] Precise repeat airborne laser surveys were conducted over the major ice caps in the Canadian Arctic Archipelago in the spring of 1995 and 2000 in order to measure elevation changes in the region. Our measurements reveal thinning at lower elevations (below 1600 m) on most of the ice caps and glaciers but either very little change or thickening at higher elevations in the ice cap accumulation zones. Recent increases in precipitation in the area can account for the slight thickening where it was observed but not for the thinning at lower elevations. For the northern ice caps on the Queen Elizabeth Islands, thinning was generally <0.5 m yr−1, which is consistent with what would be expected from the warm temperature anomalies in the region for the 5 year period between surveys, and appears to be a continuation of a trend that began in the mid-1980s. Farther south, however, on the Barnes and Penny ice caps on Baffin Island, this thinning was much more pronounced at over 1 m yr−1 in the lower elevations. Here temperature anomalies were very small, and the thinning at low elevations far exceeds any associated enhanced ablation. The observations on Barnes, and perhaps Penny, are consistent with the idea that the observed thinning is part of a much longer term deglaciation, as has been previously suggested for Barnes ice cap. On the basis of the regional relationships between elevation and elevation change in our data, the 1995–2000 mass balance for the archipelago is estimated to be −25 km3 yr−1 of ice, which corresponds to a sea level increase of 0.064 mm yr−1. This places it among the more significant sources of eustatic sea level rise, though not as substantial as the Greenland ice sheet, Alaskan glaciers, or the Patagonian ice fields.