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

该项目将利用气候模型模拟来协助古气候界解释冰芯记录，并提供太平洋气候变异性的宝贵的、全流域的古历史，供更广泛的科学界使用。这项工作的结果预计将揭示太平洋的基本背景状况与个别厄尔尼诺/拉尼娜事件之间的相互作用效应在地球气候历史的较长时期内是如何变化的。因此，加强对太平洋十年期变率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，以减轻未来预期的经济和社会影响。该研究团队通过俄亥俄州州立大学伯德极地和气候研究中心的教育和推广计划不断传播他们的研究成果，致力于为学生，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女博士后研究员提供支持、培训和指导。太平洋表面温度每几十年在温暖和寒冷阶段之间振荡，太平洋背景状态的这些数十年变化影响区域和全球气候。在区域一级，太平洋的基本暖或冷背景状态调节个别厄尔尼诺/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现象对全球气候的影响，必须了解太平洋的背景状况。然而，由于相对较短的现代仪器观测记录，我们目前对这种行为的理解是有限的。因此，其他方法，如建模和/或使用古气候代用数据，往往被用来定义太平洋温度之前的仪器期间。该项目的主要目标是利用全球气候模式模拟和太平洋盆地周围四个不同区域现有的冰芯记录，建立太平洋十年期变率及其对上千年全球气候影响的历史。每个冰芯主要通过年度层厚度（积累），稳定的水同位素比率（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）提供局部到全球尺度气候的记录。每个记录提供了降水和温度的独特见解，这将被用来重建整个流域的太平洋变化的历史。模型模拟将有助于改进对冰芯数据的解释，并促进对所观察到的冰芯对太平洋气候变异性的反应的基本机制的理解。冰芯记录的使用也有助于评估和可能提高模型的能力，以物理地代表负责整个太平洋的局部气候变化的关键过程。该奖项反映了NSF的法定使命，并已被认为是值得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的支持。

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.