The internal stratigraphy of snow and ice as imaged by ground-penetrating radar may serve as a source of information on past accumulation. This study presents results from two ground-based radar surveys conducted in Greenland in 2007 and 2015, respectively. The first survey was conducted during the traverse from the ice-core station NGRIP (North Greenland Ice Core Project) to the ice-core station NEEM (North Greenland Eemian Ice Drilling). The second survey was carried out during the traverse from NEEM to the ice-core station EGRIP (East Greenland Ice Core Project) and then onwards to Summit Station. The total length of the radar profiles is 1427 km. From the radar data, we retrieve the large-scale spatial variation of the accumulation rates in the interior of the ice sheet. The accumulation rates range from 0.11 to 0.26 m a−1 ice equivalent with the lowest values found in the northeastern sector towards EGRIP. We find no evidence of temporal or spatial changes in accumulation rates when comparing the 150-year average accumulation rates with the 321-year average accumulation rates. Comparisons with regional climate models reveal that the models underestimate accumulation rates by up to 35% in northeastern Greenland. Our results serve as a robust baseline to detect present changes in either surface accumulation rates or patterns.

中文翻译：

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过去 300 年来格陵兰中北部的地表积累

探地雷达成像的冰雪内部地层可以作为过去积累的信息来源。本研究分别介绍了 2007 年和 2015 年在格陵兰岛进行的两次地面雷达调查的结果。第一次调查是在从冰芯站 NGRIP（北格陵兰冰芯项目）到冰芯站 NEEM（北格陵兰 Eemian Ice Drilling）期间进行的。第二次勘测是在从 NEEM 到冰芯站 EGRIP（东格陵兰冰芯项目）然后继续到顶峰站的过程中进行的。雷达剖面总长度为 1427 公里。从雷达数据中，我们检索了冰盖内部积累速率的大尺度空间变化。累积速率范围为 0.11 至 0.26 ma-1在向 EGRIP 的东北部分发现的冰当量最低。在比较 150 年的平均积累率和 321 年的平均积累率时，我们没有发现积累率在时间或空间上发生变化的证据。与区域气候模型的比较表明，这些模型低估了格陵兰岛东北部的积累率高达 35%。我们的结果可作为检测表面积累率或模式当前变化的可靠基线。