Southeast Greenland high accumulation rates derived from firn cores and ground-penetrating radar
Southeast Greenland high accumulation rates derived from firn cores and ground-penetrating radar
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格陵兰岛东南部的高积累率源于冷杉核和探地雷达
DOI：
10.3189/2013aog63a358
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发表时间：
2013
影响因子：
2.9
通讯作者：
V. B. Spikes
中科院分区：
文献类型：
--
作者：
C. Miège;R. Forster;J. Box;E. Burgess;J. McConnell;D. Pasteris;V. B. Spikes
摘要 尽管东南部地区的积雪面积仅占格陵兰冰盖的 14%，但其积雪率最高，因此约占总积雪量的 30%。我们展示了 2010 年北极圈穿越期间通过地球化学分析测定的三个 50 m 冷杉岩芯获得的积累率。我们使用 400 MHz 探地雷达 (GPR) 跟踪冷杉核心之间的连续内部反射水平。探地雷达数据与冷杉核的深度年龄尺度相结合，提供了沿 70 公里横断面的累积率。我们沿着从 ∼2350 到 ∼1830m 的海拔梯度，了解渐进的表面融化可能如何影响对冷杉核进行化学测年和用探地雷达追踪内层的能力。从冷杉核心来看，我们发现下部地点的平均积雪量比上部地点增加了 52%（∼0.43 m w.e. a-1），并且年际变化更大。探地雷达剖面显示，积累率受到地表地形起伏的影响，7 公里范围内的变化高达 23%。这些测量结果证实了东南部存在高积累率，正如校准区域气候模型 Polar MM5 所预测的那样。
Abstract Despite containing only 14% of the Greenland ice sheet by area, the southeastern sector has the highest accumulation rates, and hence receives ∼30% of the total snow accumulation. We present accumulation rates obtained during our 2010 Arctic Circle Traverse derived from three 50 m firn cores dated using geochemical analysis. We tracked continuous internal reflection horizons between the firn cores using a 400 MHz ground-penetrating radar (GPR). GPR data combined with depth-age scales from the firn cores provide accumulation rates along a 70 km transect. We followed an elevation gradient from ∼2350 to ∼1830m to understand how progressive surface melt may affect the ability to chemically date the firn cores and trace the internal layers with GPR. From the firn cores, we find a 52% (∼0.43 m w.e. a-1) increase in average snow accumulation and greater interannual variability at the lower site than the upper site. The GPR profiling reveals that accumulation rates are influenced by topographic undulations on the surface, with up to 23% variability over 7 km. These measurements confirm the presence of high accumulation rates in the southeast as predicted by the calibrated regional climate model Polar MM5.