Collaborative Research: Holocene glacier length variations along the spine of the American Cordilleras and their climatic significance

合作研究：沿美洲科迪勒拉山脉脊柱的全新世冰川长度变化及其气候意义

• 批准号: 1805892
• 负责人: Brent Goehring
• 金额: $ 15.3万
• 依托单位: Tulane University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1805892&HistoricalAwards=false
• 关键词: Collaborative; Research; Holocene; glacier; length

The worldwide retreat of glaciers over the past century is one of the clearest signals of global warming, but it raises two basic questions that remain hazy: how anomalous are current glacier extents, and what were long-term glacier trends prior to the industrial era? This project will reconstruct how often during the Holocene (the last 11,000 years) a dozen glaciers down the length of the Americas, from the Arctic to Patagonia, were larger versus smaller than today. We take a community-based approach to reduce cost, with active glacier scientists collecting samples gratis during their own field campaigns to contribute to this project. Our results will provide a geologic lens through which to view modern climate change, and offer a paleo-test for computer models used to simulate glacier responses to future warming -- important to freshwater resources in some areas and global sea level rise. We will reconstruct glacier histories by applying the in situ 14C-10Be chronometer to several samples of proglacial bedrock at each glacier terminus. This technique is able to determine what portion of the Holocene a glacier advanced beyond and retreated behind its current terminus by quantifying the buildup of both 14C and 10Be during periods of exposure and the preferential loss of 14C during episodes of ice cover due to its much shorter half-life. Our latitudinal transect is designed to maximize understanding of how glaciers responded to orbital variations, as well as how climate may have been coupled between the low and high latitudes and across the hemispheres. Given that Holocene glacier trends may have varied substantially with latitude, the broad scale of our reconstructions will also provide the context needed for evaluating current glacier retreat around the world.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.

过去一个世纪全球范围内冰川的退缩是全球变暖最明显的信号之一，但它提出了两个仍然模糊的基本问题：当前冰川范围有多么异常，以及工业时代之前的长期冰川趋势是什么？该项目将重建全新世（过去 11,000 年）期间，从北极到巴塔哥尼亚，美洲各地的十几个冰川比今天更大或更小的情况。我们采取基于社区的方法来降低成本，活跃的冰川科学家在他们自己的实地活动中免费收集样本，为该项目做出贡献。我们的研究结果将提供一个地质视角来观察现代气候变化，并为用于模拟冰川对未来变暖的反应的计算机模型提供古测试——这对某些地区的淡水资源和全球海平面上升很重要。我们将通过将原位 14C-10Be 天文计时器应用于每个冰川终点的几个前冰川基岩样本来重建冰川历史。该技术能够通过量化暴露期间 14C 和 10Be 的积累以及由于其半衰期短得多而在冰盖期间优先损失的 14C 来确定全新世冰川的哪一部分前进超过并后退到其当前终点。我们的纬度样线旨在最大限度地了解冰川如何响应轨道变化，以及低纬度和高纬度之间以及整个半球的气候如何耦合。鉴于全新世冰川趋势可能随纬度的不同而发生很大变化，我们的大规模重建也将为评估当前世界各地冰川退缩提供所需的背景。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。