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

这项研究由密歇根大学、约翰·霍普金斯大学、加州大学圣地亚哥·斯克里普斯海洋研究所和明尼苏达大学德卢斯分校的科学家共同努力，将重建过去75万年来南加州有针对性的气候间隔期间的年降雨量。利用来自圣巴巴拉盆地的现有岩心--一个在降雨事件后接收含沙河流排放的系统，随后的生物扰动最小--该项目将使用扫描X射线荧光来检测硅质碎屑物质，作为河流径流的替代。将对沉积物中的花粉进行分析，以进一步验证潮湿和干燥的气候条件。将确定关键气候间隔的多年干旱和洪水频率，捕捉年际(厄尔尼诺-南大洋)和年代际(太平洋十年振荡)气候模式。结果将被用来评估这些气候模式对二氧化碳浓度变化和轨道周期变化等强迫因素的反应。这项研究将使区域气候记录远远超出仪器数据所涵盖的时间段，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所有方面，包括会见合作者，在全国会议上发表报告，以及发表论文。以网络为基础的地球指南平台将提供基于该项目的教材，供中小学课程使用。

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.