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

这一合作项目的目标是重建阿拉斯加北极第四纪晚期的气候和冰川变化，这是北极地区少数几个山地冰川留下以前范围的实物记录的地区之一，因此对于比较低纬度地区和北极之间山区冰川变化的时间和程度很有价值。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了对比(在气候变化记录中，北大西洋地区经常被认为代表整个北半球)，目前可用的证据表明，布鲁克斯山脉的历史更接近于南半球的冰川记录。研究人员建议利用前冰期湖泊沉积物和冰川地貌的铍-10测年来建立气候变化记录和冰川波动记录，以解决围绕四个显著的全球变化间隔的问题：(1)最后一次冰盛期：气候模型模拟的全球末次盛冰期期间，阿拉斯加北极的冰川是否退缩和温度上升？(2)冰川退化：阿拉斯加北极的气候变化在多大程度上与北大西洋气候波动在消冰期相吻合？(3)全新世冰川：在(A)全新世最热时期，冰川的程度如何，和(B)新冰川作用？(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的合适山谷(有现存冰川的漂浮可到达的山谷)进行。该项目有几个教育部分，包括支持四名研究生和几名本科生，以及访问Anaktuvuk Pass社区，就气候研究和布鲁克斯山脉发表演讲。这项拟议的研究旨在对美国最北端冰川地区的冰川和气候变异性进行准确的量化记录。记录北极冰川在冰川晚期和全新世等温暖时段受到极端气候事件影响时的过去行为，可以提供宝贵的见解，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.