Collaborative Research: An ultra-high-resolution record of drought, flood, and coupled ocean-atmosphere climate oscillations in Holocene and late Quaternary Californian sediments

这项研究是密歇根大学、约翰霍普金斯大学、加州大学圣地亚哥分校斯克里普斯海洋学研究所和明尼苏达大学德卢斯分校的科学家们共同努力的结果，将重建南加州在过去75万年中特定气候间隔内的年降雨量。利用圣巴巴拉盆地现有的岩心，该系统在降雨事件发生后接收含有沉积物的河流排放，随后的生物扰动最小，该项目将使用扫描x射线荧光检测作为河流径流代表的硅塑性材料。沉积物中的花粉将被分析，以进一步验证潮湿和干燥的气候条件。多年干旱和洪水的频率将确定为关键的气候间隔，捕获年际（El Niño-Southern海洋）和年代际（太平洋年代际涛动）气候模式。结果将用于评估这些气候模式对诸如二氧化碳浓度变化和轨道周期变化等强迫的响应。这项研究将把区域气候记录扩展到仪器数据所覆盖的时间段之外，提高我们理解和预测未来水文和气候变化的能力。研究生将参与研究的各个方面，包括与合作者会面，在国家会议上发表论文和发表论文。基于网络的平台Earthguide将托管基于该项目的教育材料，用于中小学课程。

This research-- a collaborative effort between scientists from the University of Michigan, Johns Hopkins University, the University of California San Diego Scripps Institute of Oceanography, and the University of Minnesota Duluth-- will reconstruct annual rainfall in Southern California during targeted climate intervals over the last 750,000 years. Using existing cores from the Santa Barbara Basin-- a system that receives sediment-laden river discharge following rainfall events, with minimal subsequent bioturbation-- the project will employ scanning X-ray fluorescence to detect siliciclastic material as a proxy for river runoff. Pollen in sediments will be analyzed to further verify wet vs. dry climate conditions. The frequency of multi-year droughts and floods will be determined for key climate intervals, capturing interannual (El Niño-Southern Ocean) and decadal (Pacific Decadal Oscillation) climate modes. Results will be used to assess the response of these climate modes to forcings such as changing CO2 concentrations and variations in orbital cycles. This study will extend the regional climate record well beyond the time period covered by instrumental data, improving our capacity to understand and predict future hydrologic and climate changes. Graduate students will be involved in all aspects of the research, including meeting with collaborators, presenting at national meetings, and publishing papers. The web-based platform Earthguide will host educational materials based on this project for use in primary and secondary school curricula.