Pacific Decadal Variability: Modulation of Global- to Regional-scale Climate over the Last Millennium

该项目将使用气候模型模拟来协助古气候界解释冰芯记录，并提供有价值的、全盆地范围的太平洋气候变化古历史，并将其提供给更广泛的科学界。这项工作的结果预计将揭示太平洋的潜在背景状态与个别厄尔尼诺/拉尼娜事件之间的相互作用效应在地球气候历史的较长背景下如何变化。因此，加强对太平洋年代际变化及其对全球和区域气候的历史影响的了解将有助于指导采取预防措施，以减轻其未来预期的经济和社会影响。该研究团队通过俄亥俄州立大学伯德极地和气候研究中心的教育和外展计划持续不断地传播他们的研究成果，致力于向学生、公众和各级政策制定者提供气候信息。此外，该项目还为代表该领域下一代科学家的一名女性博士后研究员提供支持、培训和指导。太平洋表面温度每隔几十年就会在暖相和冷相之间振荡，太平洋背景状态的这些数十年的变化会影响区域和全球气候。在区域尺度上，太平洋潜在的温暖或寒冷背景状态调节着个别厄尔尼诺/拉尼娜事件如何影响特定地区的温度和降水。为了更好地预测厄尔尼诺事件对全球气候的影响，了解太平洋的背景状况至关重要。然而，由于现代仪器观测记录相对较短，我们目前对这种行为的理解是有限的。因此，其他方法，例如建模和/或使用古气候代理数据，通常用于定义仪器测量周期之前的太平洋温度。该项目的主要目标是结合全球气候模型模拟和太平洋盆地周围四个不同区域的现成冰芯记录，建立太平洋年代际变化的历史及其过去千年对全球气候的影响。每个冰芯主要通过年层厚度（累积）、稳定水同位素比（温度）以及不溶性尘埃和主要阴离子和阳离子的浓度（大气化学）来提供当地到全球尺度的气候记录。每条记录都提供了对降水和温度的独特见解，这些见解将用于重建全盆地太平洋变化的历史。该模型模拟将有助于改进对冰芯数据的解释，并促进对驱动所观察到的冰芯对太平洋气候变化的响应的潜在机制的理解。冰芯记录的使用还有助于评估并可能增强模型能力，以物理方式代表导致整个太平洋地区气候变化的关键过程。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。

This project will use climate model simulations to assist the paleoclimate community with the interpretation of ice core records and provide a valuable, basin-wide paleo history of Pacific climate variability which will be made available to the broader scientific community. Results from this work are expected to reveal how the interactive effects between the underlying background state of the Pacific and individual El Niño/La Niña events have changed over the longer context of Earth's climate history. Thus, enhanced knowledge of Pacific decadal variability and its historical effects on both global and regional climate will help guide precautionary efforts taken to ameliorate their anticipated economic and societal impacts in the future. This team of researchers continuously and consistently disseminate their research results through the Education and Outreach Program at The Ohio State University's Byrd Polar and Climate Research Center, dedicated to providing climate information to students, the public and policymakers at all levels. In addition, this project provides support, training, and mentoring for a female postdoctoral researcher representing the next generation of the scientists in this field.Pacific Ocean surface temperatures oscillate between warm and cold phases every few decades, and these multi-decadal shifts in the background state of the Pacific Ocean affect both regional and global climate. On the regional scale, the underlying warm or cold background state of the Pacific Ocean modulates how individual El Niño/La Niña events affect temperature and precipitation in specific areas. To better predict the impacts of El Niño events on global climate, it is essential to know the background state of the Pacific Ocean. However, our current understanding of this behavior is limited due to relatively short modern instrument observational records. Thus, other methods, such as modeling and/or the use of paleoclimate proxy data, are often used to define Pacific Ocean temperatures prior to the instrumental period. The key goal of this project is to establish a history of Pacific decadal variability and its global climatic influences for the past millennium using a combination of global climate model simulations and readily available ice core records from four different regions around the Pacific Basin. Each ice core provides records of local to global scale climate primarily through annual layer thicknesses (accumulation), stable water isotopic ratios (temperature), and concentrations of both insoluble dust and major anions and cations (atmospheric chemistry). Each record provides distinct insights on precipitation and temperature which will be used to reconstruct the history of basin-wide Pacific variability. The model simulations will serve to improve interpretation of the ice core data and advancing the understanding of underlying mechanisms driving the observed ice core responses to Pacific climate variability. The use of the ice core records also helps evaluate and possibly enhance model capabilities to physically represent critical processes responsible for local climate variability across the Pacific.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.