Collaborative Research: Resolving centennial- to millennial-scale trends in glacier extent and lake sedimentation in the Brooks Range, Arctic Alaska

这个合作项目的目标是重建阿拉斯加北极地区的晚第四纪气候和冰川变化，阿拉斯加是北极地区少数几个山地冰川留下其以前范围的物理记录的地区之一，这对于比较低纬度地区和北极地区山地冰川变化的时间和范围很有价值。布鲁克斯山脉的气候和冰川历史的几个特征与北大西洋地区的气候和冰川历史形成对比（北大西洋地区在气候变化记录中经常被认为代表整个北半球），目前可获得的证据表明，布鲁克斯山脉的历史与南半球的冰川记录更为相似。研究人员建议利用前冰期湖泊沉积物和冰川特征的铍-10定年法，从湖泊沉积物和冰川波动记录中发展气候变化记录，以解决围绕四个显著全球变化间隔的问题：(1)末次极大期：在全球LGM期间，北极阿拉斯加的冰川是否退缩和温度升高，正如气候模型所模拟的那样？(2)消冰：在消冰期间，阿拉斯加北极地区的气候变化与北大西洋气候波动的重合程度如何？(3)全新世冰期：在(a)全新世热最大值和(b)新冰期期间，冰川的范围是多少？(4)小冰期：布鲁克斯山脉是更潮湿还是更干燥？研究将在布鲁克斯山脉中北部合适的山谷（有现存冰川的水上飞机可到达的山谷）进行。该项目有几个教育组成部分，包括支持四名研究生和几名本科生，以及访问阿纳克图伍克山口社区，就气候研究和布鲁克斯山脉发表演讲。拟议的研究旨在为美国最北端冰川地区的冰川和气候变化提供准确的年代和定量记录。记录北极冰川在冰期晚期和全新世等温暖间隔期间受到极端气候事件影响时的过去行为，可以提供有价值的见解，帮助更好地预测对未来变化的反应。

The goal of this collaborative project to reconstruct late Quaternary climate and glacier change in Arctic Alaska, one of few regions in the Arctic where mountain glaciers have left physical records of their former extent, making it valuable for comparing the timing and extent of mountain glacier variability between the lower latitudes and the Arctic. Several features of the climate and glacier history of the Brooks Range contrast with those from the North Atlantic region (which is often taken to represent the entire Northern Hemisphere in records of climate change) and currently available evidence indicates that the history of the Brooks Range more closely resembles glacier records from the southern Hemisphere. The investigators propose to develop records of climate change from lake sediments and records of glacier fluctuations using proglacial lake sediments and beryllium-10 dating of glacial features to address questions centered around four intervals of pronounced global change: (1) Last Glacial Maximum: Did glaciers retreat and temperatures increase in Arctic Alaska during the global LGM, as has been simulated by climate models? (2) Deglaciation: To what extent did climate change in Arctic Alaska coincide with North Atlantic climate fluctuations during deglaciation? (3) Holocene Glaciation: What was the extent of glaciers during (a) the Holocene thermal maximum, and (b) Neoglaciation? (4) Little Ice Age: Was it wetter or drier in the Brooks Range? The research will take place in suitable valleys (floatplane accessible valley with extant glaciers) in the north­central Brooks Range. The project has several educational components, including support four graduate students and several undergraduate students and visits to the community of Anaktuvuk Pass to deliver presentations on climate research and the Brooks Range. The proposed research aims to produce well-dated and quantitative records of glacier and climate variability in the northernmost glaciated region of the U.S. Documenting the past behavior of arctic glaciers when subject to extreme climate events during the late glacial period and warm intervals like the Holocene can provide valuable insight to help better predict responses to future change.