Collaborative Research: Reconstructing Climate Linkages Across the Tropical Oceans Over the Last Millennium

合作研究：重建过去千年热带海洋的气候联系

• 批准号: 2202793
• 负责人: Julia Cole
• 金额: $ 53.9万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2202793&HistoricalAwards=false
• 关键词: Collaborative; Research; Reconstructing; Climate; Linkages

Year-to-year changes in the temperatures of the tropical oceans impact climate and weather around the world. The clearest example of this is the El Niño-Southern Oscillation (ENSO) system in the tropical Pacific. Warming and cooling patterns related to ENSO have major effects on droughts, floods, and tropical storms. The temperature of the tropical Atlantic and Indian also affects weather in the same types of ways. Not only that, the three ocean basins can interact with each other since the atmosphere connects them all. For example, warming in the tropical Atlantic tends to lead to wind patterns that then cool off the tropical Pacific. This means that to predict how climate variations may change in the future, one must understand the connections between the tropical oceans. However, those relationships are known to change over long timescales (multiple decades), and temperature records are short and scarce in the tropics. As a result, this problem is difficult to study with traditional observations (e.g. thermometers). Instead, this project will produce records of temperature using the geochemistry of long-lived corals. By comparing data from corals in the Pacific, Atlantic, and Indian oceans, this research will show how these oceans have interacted over the past several centuries. Comparison of the 20th century with previous centuries will reveal the influence of recent warming. This work explores whether these patterns appear in the climate models used to understand future climate change, and what physical processes are involved. Several different model groups will be used for comparison. Students and postdocs will also participate in this research. Finally, the project will develop training materials to make data and model results more accessible to those without a highly technical background. Interannual to multidecadal variability in the tropical oceans drives climate extremes that impact natural and human systems around the world. The equatorial Pacific ENSO system is particularly important, and recent work highlights that Atlantic and Indian ocean variability impact the recurrence and intensity of ENSO extremes. Multiple mechanisms drive these interactions, which are affected by natural and anthropogenic forcing. Yet the relative importance of each mechanism remains unknown, as does the time history of the inter-basin teleconnections. Closing this knowledge gap is fundamental to understanding how inter-basin interactions are influenced by external forcing and improving the accuracy of future model projections in the tropics and beyond. This study will create new paleoclimate records of sea surface temperature (SST) using the elemental and isotopic composition of coral skeletal material, in cores from centuries-old colonies in the Tropical North Atlantic (TNA) and Western Indian Ocean (WIO). These data will be combined with published data to reconstruct pre-instrumental SST for these regions and assess inter-basin interactions. The study will also explore the relationship of these patterns to external forcing. The project will evaluate the degree to which interbasin interactions are manifest across relevant model simulations. Insights from coral proxies will be explored with the ensemble of isotope-enabled Last Millennium Ensemble simulations: the study will analyze existing iCESM output, including ‘single forcing’ experiments to diagnose individual external influences on climate and isotopic variability, and perform targeted sensitivity experiments isolating the isotopic signatures associated with particular dynamical mechanisms.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.

热带海洋温度的年度变化影响了世界各地的气候和天气。最清楚的例子是热带太平洋地区的厄尔尼诺南振荡（ENSO）系统。与ENSO相关的变暖和冷却模式对干旱，地板和热带风暴有重大影响。热带大西洋和印度人的温度也以相同类型的方式影响天气。不仅如此，三个海洋鲈鱼可以互相相互作用，因为大气将它们全部连接起来。例如，热带大西洋中的变暖倾向于导致风向模式，然后冷却热带太平洋。这意味着要预测将来气候变化可能会发生变化，必须了解热带海洋之间的联系。但是，已知这些关系会在长时间的尺度上发生变化（数十年），并且在热带中，温度记录短而稀缺。结果，对于传统观察结果（例如温度计）很难研究这个问题。相反，该项目将使用长寿命珊瑚的地球化学产生温度记录。通过比较太平洋，大西洋和印度洋珊瑚的数据，这项研究将表明这些海洋在过去几个世纪中如何相互作用。 20世纪与前几个世纪的比较将揭示最近变暖的影响。这项工作探讨了这些模式是否出现在用于了解未来攀登变化以及涉及哪些物理过程的攀登模型中。几个不同的模型组将用于比较。学生和博士后还将参加这项研究。最后，该项目将开发培训材料，以使数据和模型结果更容易访问没有技术背景的人。热带海洋中多年多次变化的年际变化驱动着影响世界各地自然和人类系统的极端。赤道太平洋ENSO系统尤为重要，最近的工作强调了大西洋和印度洋变异性会影响ENSO极端的复发和强度。多种机制驱动了这些相互作用，这些相互作用受自然和人为强迫的影响。然而，每种机制的相对重要性仍然未知，巴丁间远程连接的时间历史也是如此。缩小这种知识差距是了解如何受到外部强迫和改善热带及其他模型项目的准确性的影响的基础。这项研究将在热带北大西洋（TNA）和印度洋西洋（WIO）的核心（WIO）中的岩心中，使用珊瑚骨骼材料的元素和同位素组成创造新的古气候记录（SST）。这些数据将与已发布的数据结合使用，以重建这些区域和评估 - 巴蛋白间相互作用的前SST。该研究还将探索这些模式与外部强迫的关系。该项目将评估相关模型模拟中盆地间相互作用表现出的程度。珊瑚代理的见解将通过上次千年合奏模拟的合奏来探索：研究将分析现有的ICESM输出，包括“单一强迫”实验，以诊断个人外部影响对气候和同位素变异性的外部影响，并隔离了针对性的敏感性，并与特定的动态统计范围隔离了统计范围，以构成了统计的统计范围。使用基金会的智力优点和更广泛的影响审查标准通过评估来支持。