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

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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.