Core Stratigraphy and Paleotemperature Estimates to Characterize Last Interglacial Tropical Pacific Climate Variability and El Nino Southern Oscillation During MIS 5e

核心地层学和古温度估计来表征 MIS 5e 期间末次间冰期热带太平洋气候变化和厄尔尼诺南方涛动

• 批准号: 2317228
• 负责人: Gerald Rustic
• 金额: $ 16.67万
• 依托单位: Rowan University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2317228&HistoricalAwards=false
• 关键词: Core; Stratigraphy; Paleotemperature; Estimates; Characterize

Inter-annual climate variability is dominated by the El Niño Southern Oscillation (ENSO). ENSO is expressed as changes in tropical Pacific sea surface temperatures, and it impacts natural and human systems across the globe. Whether ENSO events will become stronger in the future is unclear, in part because the processes that control ENSO are not fully understood. Past ENSO activity can be reconstructed using geochemical proxy evidence from ocean sediments from the eastern equatorial Pacific. The last warm climate period, known as Marine Isotope Stage 5e (MIS 5e), occurred ~119,000-126,000 years ago. Thus, Eastern Pacific sediments from MIS 5e record ENSO behavior during a previous warm state. This research will characterize MIS 5e sediments in an eastern equatorial Pacific sediment core using the shell chemistry of foraminifera. These new records will provide reliable age control for the sediment core. The data from this core can then be compared with paleoclimate data from other locations. The study will support outreach efforts to broaden participation in STEM and in the geosciences through meaningful undergraduate research opportunities. Undergraduate research assistants will be involved in all phases of the project. The geochemical analyses will be a key component of a summer workshop for undergraduates. This will give the students valuable experience on modern analytical techniques. ENSO’s behavior in response to elevated atmospheric carbon dioxide is not well constrained as our understanding of the mechanisms controlling tropical Pacific variability is incomplete. Reconstructions of ENSO during previous warm periods, and in particular the last interglacial (MIS 5e) are limited. Such reconstructions would enable testing of ENSO’s relationship with changing climate background conditions, orbital forcing, and seasonal changes in the absence of modern carbon dioxide forcing. The eastern equatorial Pacific cold tongue region is a center-of-action for ENSO, but sediment cores with adequate material, resolution, and characteristic are sparse. This research will generate a stable isotope and trace elemental stratigraphy using surface and subsurface foraminifera to identify and characterize MIS 5e sediments in an eastern equatorial Pacific sediment core. Generation of a long-term surface and subsurface stratigraphy spanning the last glacial maximum to MIS 5e will allow the sediments to be characterized for composition, accumulation rates and resolution, enabling future, high-resolution analysis of tropical Pacific variability using foraminiferal geochemical proxies, and allow for testing of key hypotheses of ENSO control.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.

年际气候变化主要是厄尔尼诺南方涛动（ENSO），表现为热带太平洋海面温度的变化，它影响全球的自然和人类系统。ENSO 事件未来是否会变得更强。不清楚，部分原因是我们尚未完全了解控制 ENSO 的过程，可以使用来自赤道东部太平洋海洋沉积物的地球化学替代证据来重建最后一个温暖气候时期，即海洋同位素阶段。 MIS 5e (MIS 5e) 发生于约 119,000-126,000 年前，因此，MIS 5e 的东太平洋沉积物记录了先前温暖状态下的 ENSO 行为。本研究将使用 赤道东太平洋沉积物核心的 MIS 5e 沉积物特征。这些新记录将为沉积物岩心提供可靠的年龄控制，然后可以将来自该岩心的数据与其他地点的古气候数据进行比较。研究将通过有意义的本科生研究助理来支持扩大对 STEM 和地球科学的参与，地球化学分析将是本科生夏季研讨会的重要组成部分。为学生提供有关现代分析技术的宝贵经验。由于我们对控制热带太平洋变率的机制的理解不完整，ENSO 对大气二氧化碳升高的反应并没有得到很好的限制。 (MIS 5e) 是有限的，这样的重建将能够在没有现代二氧化碳强迫的情况下测试 ENSO 与变化的气候背景条件、轨道强迫和季节变化的关系。对于 ENSO，但具有足够材料、分辨率和特征的沉积岩芯很少。这项研究将利用地表和地下有孔虫生成稳定同位素和痕量元素地层，以识别和表征 MIS。赤道东太平洋沉积岩芯中的 5e 沉积物的生成涵盖末次盛冰期至 MIS 5e 的长期地表和地下地层，将能够对沉积物的成分、积累速率和分辨率进行表征，从而实现未来的高分辨率分析。使用有孔虫地球化学代理来研究热带太平洋变化，并允许测试 ENSO 控制的关键假设。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力评估进行评估，被认为值得支持优点和更广泛的影响审查标准。