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.

该项目旨在表征亚洲夏季和冬季季风循环以及在过去的4.5万年中，使用一套来自洞穴的Speleothem记录，这些记录延伸到了老挝和越南之间的关键地理鸿沟，两个国家，两个国家，两个国家都有非常独特的季节性降雨量，这些洞穴延伸了洞穴。这项工作的总体目标是探索夏季和冬季亚洲季风对不断变化的外部驱动因素的动态反应，例如日照和内部气候变异性，这将有助于提高对易受伤害地区大规模水文变异性的理解。具体而言，研究人员将利用多个环境示踪剂（碳和氧同位素，诸如镁/钙，放射性碳，放射性碳）在精确延续的跨越孢子中开发新的过去气候记录，至少在过去的〜4.5千年中。此外，详细的洞穴监控程序将有助于解释从Speleothems获得的数据。结果将与过去气候变异性和最新气候模型模拟的其他区域和全球记录集成，以诊断在梅萨地区的千禧年时间尺度上驱动氢气候变异性的主要机制。这项研究将解决以下具体目标：（1）确定MSEA氢化气候对轨道和千禧一代强迫的夏季和秋季/冬季响应，（2）确定MSEA氢化气候对decadal decadal decadal对多体积尺度海面温度变化的响应，以及（3）与其他可用的记录一起使用Spatiotal模式，该模型与Spatiotal spatiotal模式合成。分析将使我们对夏季和秋季季风差异的动力学机制进行调查。来自三个研究地点的棘氧同位素记录将成为夏季季风强度的代理，由印度洋上游雨的程度和痕量元素测量所主导，将为每个洞穴的当地水平平衡中的过去变化提供强有力的证据，并在夏季降雨和越来越多的越来越多的降雨范围内录制了较广泛的降雨。通过产生定量且日期良好的多千年气候记录，从speleothems产生了弱势区域的氢化气候。该项目将为几个本科生（包括夏季研究经验）和一名研究生（博士学位）学生提供科学培训，指导和专业发展，以及三所大学的博士后研究员，包括两家少数派服务机构。此外，该项目将支持早期的职业科学家。该项目的结果将是美国和研究区（老挝/越南）正在进行和新开发的公共宣传活动的一部分，涉及学生和博士后。该项目还将培养国际和跨学科的合作，包括与当地社区。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估标准来评估值得支持的。