Development of Precipitation, Evaporation and Temperature Records from Tropical Lake Sediments and Cave Deposits for the last 700,000 years

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。全球气温上升对人类和生态系统的影响在世界各地各不相同。在热带地区，影响主要体现在水资源供应方面。保存在洞穴和湖泊中的沉积物为了解热带环境如何应对过去的气候变化提供了关键的见解。这项研究将从秘鲁的洞穴沉积物和湖泊沉积物中建立一个70万年的记录，以了解全球气候变化如何影响亚马逊盆地上游的降水、温度和湿度。这项工作的发现将适用于了解气候变化对该地区的影响，并扩展到全球，因为亚马逊是世界上最大的热带雨林的所在地，也是全球碳循环的重要调节器。该项目将整合三所研究型大学和一所本科文理学院的研究人员。本科生将与研究生在拟议工作的各个方面进行交流，一名博士后将驻扎在文理学院，并与研究型大学的团队合作。此外，科学家将与秘鲁的教师和学生合作，建立一个监测地区洞穴、湖泊和降水的项目，并开展一个旨在由社区成员领导的气候变化教育的公共宣传项目。研究人员将通过开发水文和气候变化实践模块，扩大少数族裔学生对地球科学的参与，这是密歇根大学地球夏令营的一部分，这是一个面向高中生的体验式学习项目。研究人员将利用70万年的Junín湖沉积物记录和附近洞穴的沉积物，结合对一系列古气候代用物的分析，得出近70万年亚马逊河上游流域降水-蒸发平衡和温度的综合记录。2015年，美国国家科学基金会和国际大陆钻探计划资助了Junín湖岩心的成功收集，并于2019年利用大学资金收集了洞穴沉积物。研究人员将把年代准确的Junín湖钻孔岩心与精确的U-Th地质年代学合成的洞穴记录结合起来，并将利用这些档案建立降水、蒸发和温度的记录，这将使我们的新数据与现有记录相结合，以研究亚马逊盆地的耦合气候系统（季风强度和大西洋经向翻转环流），不同边界条件下的气候敏感性，和水文变化期间的大和快速变化的强迫。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 award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The influence of increasing global temperatures on people and ecosystems varies across the world. In tropical regions, the impact is felt mostly in terms of water availability. Deposits preserved in caves and lakes provide key insights into how tropical environments responded to past climate change. This study will build a 700 thousand year-long record from cave deposits and lake sediments in Peru to understand how a changing global climate affects precipitation, temperature and humidity in the upper reaches of the Amazon Basin. The findings from this work will apply to understanding the impacts of climate change in this region and extend globally, as the Amazon is home to the world’s largest rainforest and an important regulator of the global carbon cycle. This project will integrate researchers at three research universities and one undergraduate liberal arts college. Undergraduate students will interface with graduate students through all aspects of the proposed work, and a postdoctoral fellow will be based at the liberal arts institution and will work with teams at the research universities. In addition, scientists will collaborate with faculty and students in Peru to establish a monitoring program for regional caves, lakes and precipitation, and on a public outreach program aimed at climate change education led by community members. Researchers will expand participation of underrepresented minority students in the Earth sciences through development of a hands-on hydrology and climate change module as part of the University of Michigan Earth Camp, an experiential learning program for high school students.Researchers will combine analyses of a suite of paleoclimate proxies using both the 700,000 year-long Lake Junín sediment record and deposits from nearby caves, to produce a near-continuous, composite record of precipitation-evaporation balance and temperature for the upper Amazon Basin for the last 700,000 years. The National Science Foundation and the International Continental Drilling Program funded the successful collection of the Lake Junín drill core in 2015, and the cave deposits were collected in 2019 using university funds. Researchers will combine the well-dated Lake Junín drill core with a composite speleothem (cave) record dated by precise U-Th geochronology, and will use these archives to build records of precipitation, evaporation, and temperature, that will enable synthesis of our new data with existing records to investigate coupled climate systems in the Amazon Basin (monsoon strength and Atlantic meridional overturning circulation), climate sensitivity under different boundaryconditions, and hydrologic change during periods of large and rapid changes in forcing.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.