Collaborative Research: P2C2--Speleothem Constraints on Seasonal Hydroclimate Variability in Mainland Southeast Asia since the Late Pleistocene

合作研究：P2C2--晚更新世以来东南亚大陆洞穴水文季节变化的制约

• 批准号: 2102976
• 负责人: William McGee
• 金额: $ 16.41万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102976&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Speleothem; Constraints

This project aims to characterize the Asian summer and winter monsoon circulation and local hydroclimate across Mainland Southeast Asia (MESA) during the last ~45 thousand years using a suite of speleothem records from caves that extend across a critical geographical divide between Laos and Vietnam, two countries with very distinct seasonal rainfall climatologies. The overarching goal of this work is to explore the dynamic response of summer and winter Asian monsoon variability to changing external drivers, such as insolation, and internal climate variability which will contribute to improved understanding of large-scale hydrological variability in a vulnerable region. Specifically, the researchers will develop a new set of past climate records utilizing multiple environmental tracers (Carbon and Oxygen isotopes, trace elements such as Magnesium/Calcium, radiocarbon) in precisely dated speleothems spanning at least the last ~45 thousand years. Additionally, a detailed cave monitoring program will aid the interpretation of data obtained from the speleothems. The results will be integrated with other regional and global records of past climate variability and state-of-the-art climate model simulations to diagnose the dominant mechanisms driving hydroclimate variability on sub-decadal to millennial timescales in the MESA region. The research will address the following specific objectives: (1) Determine the summer and fall/winter response of MSEA hydroclimate to orbital and millennial-scale forcing, (2) Determine the response of MSEA hydroclimate to decadal to multidecadal scale sea surface temperature variability, and (3) Synthesize data with other available records to elucidate the spatiotemporal patterns of MSEA hydroclimate, which, combined with paleoclimate model analyses, will allow us investigation of the dynamical mechanisms underlying summer and fall/winter monsoon variability. Speleothem oxygen isotope records from three study sites will serve as a proxy for summer monsoon intensity, dominated by the degree of upstream rainout over the Indian Ocean and trace element measurements will provide robust evidence for past variations in local water balance at each cave site, with Laos sites recording summer rainfall and Vietnam sites recording fall/winter rainfall.The potential Broader Impacts include a better understanding of the monsoon dynamics and related hydroclimate in a vulnerable region by generating quantitative and well-dated multi-millennial climate records from speleothems. The project will provide scientific training, mentorship and professional development for several undergraduate (including summer research experience) and one graduate (Ph.D.) students, as well as one postdoctoral researcher at three universities including two minority serving institutions. Additionally, the project will support an early career scientist. The results of the project will be part of ongoing and newly developed public outreach activities both in The US and the study region (Laos/Vietnam) involving students and postdocs. The project will also foster international and transdisciplinary collaborations including with local communities.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.

该项目旨在利用一系列来自洞穴的洞穴记录来描述过去约 45000 年亚洲夏季和冬季季风环流以及整个东南亚大陆 (MESA) 的当地水文气候，这些洞穴横跨老挝和越南之间的关键地理分界线。具有非常独特的季节性降雨气候的国家。这项工作的总体目标是探索夏季和冬季亚洲季风变率对不断变化的外部驱动因素（例如日照）和内部气候变率的动态响应，这将有助于提高对脆弱地区大规模水文变率的了解。具体来说，研究人员将利用多种环境示踪剂（碳和氧同位素、镁/钙等微量元素、放射性碳）在至少过去约 45000 年的精确年代的洞穴中开发一套新的过去气候记录。此外，详细的洞穴监测计划将有助于解释从洞穴中获得的数据。研究结果将与过去气候变化的其他区域和全球记录以及最先进的气候模型模拟相结合，以诊断 MESA 地区在十年到千年时间尺度上驱动水文气候变化的主导机制。该研究将实现以下具体目标：(1) 确定 MSEA 水文气候对轨道和千年尺度强迫的夏季和秋季/冬季响应，(2) 确定 MSEA 水文气候对十年至数十年尺度海面温度变化的响应， (3) 将数据与其他可用记录综合起来，以阐明 MSEA 水文气候的时空模式，这与古气候模型分析相结合，将使我们能够研究动力学夏季和秋季/冬季季风变化的潜在机制。来自三个研究地点的 Speleothem 氧同位素记录将作为夏季季风强度的代表，主要由印度洋上游降雨的程度决定，微量元素测量将为每个洞穴地点当地水平衡过去的变化提供有力的证据，老挝站点记录夏季降雨量，越南站点记录秋季/冬季降雨量。潜在的更广泛影响包括通过生成定量且日期明确的多千年气候记录，更好地了解脆弱地区的季风动态和相关水文气候。洞穴洞穴。该项目将为三所大学（包括两所少数族裔服务机构）的几名本科生（包括暑期研究经验）和一名研究生（博士）以及一名博士后研究员提供科学培训、指导和专业发展。此外，该项目还将支持一名早期职业科学家。该项目的结果将成为美国和研究地区（老挝/越南）正在进行的和新开发的公共外展活动的一部分，涉及学生和博士后。该项目还将促进国际和跨学科合作，包括与当地社区的合作。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。

项目成果

Glacial changes in sea level modulated millennial-scale variability of Southeast Asian autumn monsoon rainfall

海平面的冰川变化调节了东南亚秋季季风降雨的千禧年尺度变化

• DOI: 10.1073/pnas.2219489120
• 发表时间: 2023-07-04
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Patterson, Elizabeth W.;Johnson, Kathleen R.;Griffiths, Michael L.;Kinsley, Christopher W.;McGee, David;Du, Xiaojing;Pico, Tamara;Wolf, Annabel;Ersek, Vasile;Mortlock, Richard A.;Yamoah, Kweku A.;Bui, Thanh N.;Tran, Mui X.;Quoc, Do-Trong;Vo, Tri V.
• 通讯作者: Vo, Tri V.