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.

北美西部淡水的可获得性和质量与自然气候变化直接相关。在相关时间尺度上确定气候变化的能力受到观测和仪器记录持续时间较短的限制。在南加州，对长而高分辨率的古气候学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加利福尼亚州南部建立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年代良好的陆地和海洋档案进行比较。对历史数据的分析表明，埃尔西诺湖是记录南加州气候变化的绝佳地点。对该湖最深盆地的两个钻孔岩心的初步研究表明，该湖有一个相对较厚的(约10m/9000年-基于21个AMS 14C测年)、连续的全新世沉积序列，几乎没有证据表明沉积物不连续。对几个沉积学参数的分析表明，两个岩心之间的厘米级变化是一致的。这笔赠款支持使用已建立的气候敏感替代方法对取心沉积物进行进一步分析。到目前为止，两个深盆岩心的质量磁化率、总有机质和总碳酸盐的分析间隔都是1厘米。这项研究拨款侧重于另外两项分析：粒度(代表湖泊盆地和流域沉积动力学)和d18O(方解石)和d13C(方解石)(分别代表湖泊水文收支和湖泊/流域生产力)。结合北美西部和太平洋的其他古气候记录，埃尔西诺湖记录将被用来更好地描述北美西部全新世气候变异性的演变以及时空模式。此外，这一记录将提供全新世自然气候变异性的基线，南加州水管理组织--资助最初研究的组织--可以根据该基线评估目前的水管理政策。这一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。这项研究的学术价值将为描述和理解地方和区域尺度上的全新世气候变异性提供关键信息。这项研究还将有助于回答有关全新世气候演变及其与更大尺度海洋-大气动力学的关系的几个重要问题。这项工作的更广泛影响包括2名本科生和1名硕士研究生的研究经验和论文准备。学生。这项研究的结果将通过互动网站以及开发用于加州州立大学富勒顿实验室课程的实地网站，向加利福尼亚州河滨县埃尔西诺湖的公民和管理人员传播。作为瑞和少数民族服务机构，这项研究也将为CSUF在科学界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可变性提供具有社会意义的洞察，该地区的水资源管理对未来的社会经济稳定至关重要。