Benchmarking Spatial Patterns of Glacier Change

本研究将研究过去冰川前进和后退的全球模式，以分析区域环境变率的模式。在全球冰川衰退时期，世界不同地区的冰川表现不同。冰川退缩的速度随时间而变化，在某些情况下，冰川退缩被冰川生长的短间隔打断。这些不同的空间格局可以帮助科学家预测未来区域对全球环境变化的响应模式。在这个项目中，研究人员将使用各种地球科学技术分析阿拉斯加的冰川地貌，以确认过去冰川变化速度的区域差异。与世界其他地区相比，阿拉斯加是一个对过去冰川变化了解较少的地区，但它的区域冰川变化与全球模式不同。研究结果将有助于增进对过去区域环境变异性的了解，从而成为今后建模的重要数据来源。该项目更广泛的影响包括来自代表性不足群体的科学家的职业发展，以及研究生和本科生的培训。传播将包括通过阿拉斯加的国家公园和土著社区传播的学术出版物和面向公众的材料。为了更好地了解未来冰川变化的轨迹和相关的环境变率，必须阐明对全球冰川行为的更好的区域影响。因此，古气候和冰川地貌群落迫切需要详细了解区域冰川变化及其与全球格局的偏差。最后一次冰川消融期间的二氧化碳变化与山地冰川变化紧密相关。然而，这份汇编缺乏来自高纬度地区的数据。最近的研究假设，在现代，二氧化碳已经压倒了区域驱动因素，成为冰川变化的主要控制因素。拟议的研究旨在通过填补一个关键的数据缺口来解决这些问题。研究人员将测试古气候和冰川科学前沿的两个假设。(1)大气二氧化碳是山地冰川变化的主要强迫机制。(2)北大西洋地区以外的冰川在海因里希冰期前进，但在海因里希冰期结束前退缩。研究人员将从北纬高纬度地区重建一个非常详细的山地冰川记录，时间跨度从最后一次冰消期到现在。由于大陆冰盖在冰河时期覆盖了大部分北部高纬度地区，因此很少有可以提供详细的冰川冰碛序列的地点，这些地点的材料可以精确地确定年代。由于阿拉斯加州在最后一次冰川期基本上没有受到大陆冰盖的影响，而是由山地冰川主导，因此这里是一个理想的地点，可以对上次冰川消退以来的冰川变化进行基准测试和开发记录。pi将结合在阿拉斯加西部启示山脉的一个特殊的冰碛序列的宇宙成因铍-10测年与数字测绘和冰川平衡线高度分析，以测试他们的假设和基准山区冰川变化的区域记录。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research will investigate global patterns of past glacier advance and retreat to analyze regional patterns of environmental variability. During times of global glacier recession, glaciers in different parts of the world behaved differently. The rate of glacier retreat varied through time, and in some cases, glacier retreat was interrupted by short intervals of glacier growth. These differential spatial patterns can help scientists predict future patterns of regional response to global environmental variability. In this project, using various earth science techniques, investigators will analyze glacial landforms in Alaska to affirm regional differences in rates of past glacier change. Alaska is a region where past glacier change is less well understood than other parts of the world, but one where regional glacier change was different from global patterns. Findings will contribute to an improved understanding of past regional environmental variability and thereby be an important data source for future modelling. The project's broader impacts include the career advancement of a scientist from an underrepresented group and includes the training of graduate and undergraduate students. Dissemination will include academic publications and public-oriented materials disseminated via national parks and native communities in Alaska. To better understand the trajectory of future glacier change, and related environmental variability, better regional influences on glacier behavior across the planet must be elucidated. For this reason, detailed knowledge of regional glacier change and their deviations from the global pattern are critically needed for paleoclimate and glacial-geomorphology communities. Carbon dioxide changes during the last deglaciation were tightly coupled to mountain glacier change. Yet, this compilation lacked data from the high latitudes. Recent research hypothesizes that carbon dioxide in modern times has overwhelmed regional drivers and has become the dominant control on glacier change. The proposed research aims address these ideas by filling in a key data gap. The investigators will test two hypotheses that are at the forefront of paleoclimate and glacier science. (1) Atmospheric carbon dioxide is the primary forcing mechanism of mountain glacier change. (2) Glaciers outside the North Atlantic region advanced during Heinrich stadials, but retreated prior to their terminations. The researchers will reconstruct a highly detailed mountain glacier record from the high northern latitudes, temporally spanning from the last deglaciation to the present. Because continental ice sheets covered most of the high northern latitudes during Ice Ages, there are few accessible sites that offer detailed glacier moraine sequences with materials that can be precisely dated. Because Alaska remained largely untouched by continental sheets during the last glacial period and was instead dominated by mountain glaciers, this is an ideal location to benchmark and develop a record of glacier change since last deglaciation. The PIs will combine cosmogenic Beryllium-10 dating of an exceptional moraine sequence in the Revelation Mountains in western Alaska with digital mapping and glacier equilibrium-line altitude analysis to test their hypotheses and to benchmark a regional record of mountain glacier change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.