Collaborative Research/RUI: Assessing Multi-scale Holocene Climate Variability in Western North America Using Sediments from Lake Elsinore (Southern CA)

合作研究/RUI：利用埃尔西诺湖（加利福尼亚州南部）的沉积物评估北美西部多尺度全新世气候变化

• 批准号: 0602245
• 负责人: Steven Lund
• 金额: $ 4.79万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0602245&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Assessing; Multi

The availability and quality of freshwater in western North America is directly linked to natural climate variability. The ability to determine climate variations on relevant time scales is limited by the short duration of observational and instrumental records. The need for long, high-resolution paleoclimatological records is particularly acute in Southern California, where over 20 million people are vulnerable to climate variability. This grant will develop the first complete terrestrial Holocene climate record for southern California using sediment from Lake Elsinore and compare this record to other well-dated terrestrial and marine archives from the region. Analysis of historical data indicates that Lake Elsinore is an excellent site for recording climate variability for southern California. Preliminary research on 2 drill cores from the lake's deepest basin indicates a relatively thick (~10m/9,000 yrs - based on 21 AMS 14C dates), continuous Holocene sediment sequence with minimal evidence for sediment discontinuities. Analyses of several sedimentological parameters reveal centimeter-scale variability that is consistent between the 2 cores. This grant supports further analysis of the cored sediment using established climate-sensitive proxy methods. To date, mass magnetic susceptibility, total organic matter, and total carbonate have been analyzed at 1cm contiguous intervals for both deep basin cores. This research grant focuses on two additional analyses: grain size (a proxy for lake basin and drainage basin sediment dynamics) and d18O(calcite) and d13C(calcite) (proxies for lake hydrologic budget and lake/drainage basin productivity, respectively). In conjunction with other paleoclimate records from western North America and the Pacific Ocean, the Lake Elsinore record will be used to better describe the evolution as well as the spatial and temporal patterns of Holocene climate variability over western North America. Furthermore, this record will provide a baseline of Holocene natural climate variability from which Southern California water management organizations - whom funded the initial research - can assess present water management policies. This record will also help to assess the sensitivity of the hydrologic system to a range of climate conditions.The intellectual merit of this study will provide critical information for characterizing and understanding Holocene climate variability on a local and regional scale. This research will also help to answer several important questions regarding Holocene climate evolution and its relationship to larger-scale ocean-atmosphere dynamics. The broader impacts of this work include research experience and thesis preparation for 2 undergraduate students and 1 M.Sc. student. The results of this study will be disseminated to the citizens and managers of Lake Elsinore, Riverside County, California through an interactive web site as well as the development of a field site for use in lab classes at Cal-State Fullerton. As a RUI and Minority Serving Institute, this research will also provide research opportunities for underrepresented individuals in the sciences at CSUF. Lastly, this research will provide socially relevant insight into future water variability in western North America, a region where water resource management is critical to future socio-economic stability.

北美西部淡水的供应和质量与自然气候变化直接相关。 确定相关时间尺度气候变化的能力受到观测和仪器记录持续时间短的限制。在南加州，对长期、高分辨率古气候记录的需求尤其迫切，那里有超过 2000 万人容易受到气候变化的影响。 这笔赠款将利用埃尔西诺湖的沉积物为南加州开发第一个完整的陆地全新世气候记录，并将该记录与该地区其他日期明确的陆地和海洋档案进行比较。历史数据分析表明，埃尔西诺湖是记录南加州气候变化的绝佳地点。对来自该湖最深盆地的 2 个钻芯的初步研究表明，存在相对较厚（~10m/9,000 年 - 基于 21 个 AMS 14C 日期）、连续的全新世沉积物序列，且沉积物不连续性的证据极少。对几个沉积学参数的分析揭示了两个岩心之间一致的厘米级变化。这笔赠款支持使用既定的气候敏感代理方法对岩心沉积物进行进一步分析。迄今为止，已对两个深盆地岩心以 1 厘米连续间隔分析了质量磁化率、总有机质和总碳酸盐。该研究资助重点关注另外两项分析：粒度（湖盆和流域沉积物动力学的代表）以及 d18O（方解石）和 d13C（方解石）（分别代表湖泊水文预算和湖泊/流域生产力）。结合北美西部和太平洋的其他古气候记录，埃尔西诺湖记录将用于更好地描述北美西部全新世气候变化的演变以及时空模式。此外，该记录将提供全新世自然气候变化的基线，资助初始研究的南加州水管理组织可以根据该基线评估当前的水管理政策。该记录还将有助于评估水文系统对一系列气候条件的敏感性。这项研究的智力价值将为在当地和区域范围内描述和理解全新世气候变化提供关键信息。这项研究还将有助于回答有关全新世气候演化及其与更大规模海洋大气动力学关系的几个重要问题。这项工作的更广泛影响包括为 2 名本科生和 1 名硕士生提供研究经验和论文准备。学生。这项研究的结果将通过一个交互式网站以及开发一个供加州州立大学富勒顿分校实验室课程使用的现场网站向加利福尼亚州河滨县埃尔西诺湖的居民和管理人员传播。作为 RUI 和少数族裔服务研究所，这项研究还将为 CSUF 科学领域代表性不足的个人提供研究机会。最后，这项研究将为北美西部未来的水资源变化提供与社会相关的见解，该地区的水资源管理对于未来的社会经济稳定至关重要。