The Last deglaciation in Greenland: demystifying the mystery interval

“最后一次冰川消退”是从最后一次冰河时代到我们目前气候状态的过渡;大约18，000到11，000年前的过渡。最后一次冰川消退是大规模全球变暖的最新自然例子，它可以帮助科学家更好地了解气候对大气二氧化碳的敏感性和格陵兰冰盖对气候变化的敏感性等科学和社会重要问题。该奖项支持对格陵兰岛过去23,000年的温度和降雪率进行新的和改进的重建。这项工作将加强对格陵兰气候历史的科学理解，可以改进格陵兰冰盖模型对过去和未来冰损失的模拟，并为气候模型模拟提供基准。该奖项支持俄勒冈州州立大学的一名研究生和华盛顿大学的一名暑期本科生实习，为STEM（科学、技术、工程和数学）劳动力做出贡献。研究人员将每年访问当地的初中和高中，进行为期一天的极地研究。该奖项支持气候反馈棋盘游戏的进一步开发和专业设计-这是一种积极学习的课堂活动，用于教授气候反馈及其在全球气候变化中的作用。研究人员将使用一种新的气候重建策略，该策略结合了来自冰芯的格陵兰岛气候信息的四个独立来源：钻孔温度，冰的水稳定同位素比，大气氮的同位素分馏，以及基于甲烷的冰芯气体年龄-冰河时代差异的经验约束;以前的重建一次只考虑两个或更少的此类约束。将在格陵兰NEEM、NGRIP和GISP 2冰芯上进行甲烷和氮同位素分馏（NH 15 N-N2）的有针对性的高精度测量，以帮助这些重建，并复制最近在GISP 2冰芯中发现的冰川NH 15 N-N2信号。该奖项支持新的模型开发，将这些新的气候信息来源纳入一个单一的重建。这项工作还包括一系列假设驱动的建模实验，使用最先进的同位素气候模型，试图回答格陵兰岛极其微弱的近场海因里希事件响应的矛盾观察，一个强大的远-该奖项反映了NSF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。

The ‘last deglaciation’ is the transition from the last Ice Age to our current climate state; a transition that took from approximately 18,000 to 11,000 years ago. The last deglaciation is the most recent natural example of large-scale global warming, which can help scientists better understand scientifically and societally important problems such as the sensitivity of climate to atmospheric carbon dioxide and the sensitivity of the Greenland ice sheet to climate change. The award supports new and improved reconstructions of Greenland temperature and snowfall rates for the last 23,000 years. The work will enhance scientific understanding of Greenland climate history, can improve Greenland ice sheet model simulations of past and future ice loss, and provides a benchmark for climate model simulations. The award supports a graduate student at Oregon State University and a summer undergraduate internship at University of Washington, contributing to the STEM (Science, Technology, Engineering and Mathematics) workforce. The researchers will visit regional middle and high schools annually for a day of polar research. The award supports the further development and professional design of a Climate Feedback boardgame – an active-learning classroom activity for teaching climate feedbacks and their role in global climate change. The researchers will use a new climate reconstruction strategy that combines four independent sources of Greenland climate information from ice cores: borehole temperatures, water stable isotope ratios of ice, isotopic fractionation in atmospheric nitrogen, and methane-based empirical constraints on the ice core gas age-ice age difference; previous reconstructions have only considered two or fewer of such constraints at a time. Targeted high-precision measurements of methane and nitrogen isotopic fractionation (∂15N-N2) will be performed on the Greenland NEEM, NGRIP and GISP2 ice cores to aid these reconstructions, and to replicate recently discovered glacial ∂15N-N2 signals in the GISP2 core. The award supports new model development to incorporate these new sources of climatic information into a single reconstruction. The work further includes a series of hypothesis-driven modeling experiments using a state-of-the-art isotope-enabled climate model that seek to answer the paradoxical observation of an extremely weak near-field Heinrich Event response in Greenland, and a strong far-field response in the global monsoon and tropical hydrology.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.