Reconstructing climate variability and aridity in the Sierra Nevada, CA, based on isotopic evidence in sediments from Swamp Lake, Yosemite

根据优胜美地沼泽湖沉积物中的同位素证据重建加利福尼亚州内华达山脉的气候变化和干旱

• 批准号: 0902218
• 负责人: Adina Paytan
• 金额: $ 20.11万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0902218&HistoricalAwards=false
• 关键词: Reconstructing; climate; variability; aridity; Sierra; Reconstructing; climate; variability; aridity; Sierra

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).An understanding of how climate in California responds to global and regional forcing mechanisms on multiple timescales is crucial for the management of scarce water resources and for predicting how natural patterns will interact with future climate warming. In light of the short instrumental record, only paleoclimatic records can provide the basis for understanding climate variability and ecosystem responses on longer timescales, capturing many cycles of the decadal and centennial-scale processes that control regional climate and determine water supplies, as well as the range of extreme conditions experienced under different climatic regimes.This grant develops new records of climatic variability in California based on isotopic evidence in the 19,000-year sedimentary sequence recovered from Swamp Lake in the central Sierra Nevada. This longer record allows high-resolution (20-50 yr) reconstructions for previously identified dry intervals in the mid- and late-Holocene, in order to better understand the decadal climate variability underlying long-term droughts. Previous work demonstrated that measurements of hydrogen isotopes (del-D) in biomarker compounds extracted from sedimentary organic matter (OM) provides a powerful paleohydrologic tool. The current project uses coupled del-D signatures of terrestrial plant and aquatic biomarkers to reconstruct past precipitation patterns, evaporative balance and water availability in the Sierra. A parallel record utilizing a suite of OM proxies (total C & N, C/N ratio, del-13C, del-15N, biomarker abundances) traces OM sources, lake productivity and other ecosystem responses to changing climate conditions. Climate reconstructions are supported by a multi-year field study to understand the isotope hydrology of the lake basin, calibration with the instrumental record, and comparisons with existing records from Swamp Lake, the Sierra Nevada, and California as a whole. The development of a decadally- to centennially-resolved record of Late Pleistocene-Holocene climatic variability for the Sierra Nevada represents a major step forward for paleoclimatic research in California. Such records are of direct societal importance because processes on these timescales determine water supplies, influence the distribution of plants and animals, and modulate the occurrence of higher-frequency events such as floods and droughts.The project provides involvement for underrepresented and minority undergraduate students in research, and participation in programs that aim to strengthen their leadership skills. Mentoring is coordinated for students from the AGEP program, and a 'first grad geology program - Geokids' at UCSC, and a K-12 education class 'Communicating ocean sciences' is offered. The project participates in the NSF-funded national education programs 'Science Diaries' and 'Kids Science Challenge' (through Pulse of the Planet, NPR). The PI also is developing an inquiry-based curriculum on the topic of paleoceangraphy and paleoclimatology.

该奖项是根据2009年的《美国复苏与再投资法》（公法111-5）资助的。了解加利福尼亚的气候如何应对多个时间表的全球和区域强迫机制如何应对稀缺水资源的管理至关重要，并预测自然模式如何与未来的气候变暖相互作用。鉴于较短的仪器记录，只有古气候记录可以为理解气候变化和生态系统的响应延长时尺度上的响应，从而捕捉到纪念十年和百年级的过程的许多周期，以控制区域气候，并确定供水供应，并确定供水的范围，以及在不同的气候状况下经历的范围的范围。从内华达山脉中部的沼泽湖回收的序列。这一较长的记录允许在中期和晚期的先前确定的干间隔内进行高分辨率（20 - 50年）重建，以便更好地了解长期干旱的际气候变化。先前的工作表明，从沉积有机物（OM）提取的生物标志物化合物中氢同位素（DEL-D）的测量提供了一种强大的古水力学工具。当前的项目使用陆地植物和水生生物标志物的Del-D签名来重建过去的降水模式，塞拉利昂的蒸发平衡和水的供应。使用OM代理套件（总C＆N，C/N比，DEL-13C，DEL-15N，生物标志物丰度）的并行记录痕迹OM来源，湖泊生产力和其他对气候条件变化的生态系统响应。一项多年的现场研究支持了气候重建，以了解湖泊盆地湖的同位素水文学，与乐器记录的校准以及与来自沼泽湖，内华达州塞拉山脉和整个加利福尼亚州的现有记录的比较。内华达山脉塞拉山脉的更新世 - 半新世气候变异性的十年至百年纪化记录的发展是加利福尼亚州古气候研究的重要一步。这些记录具有直接的社会重要性，因为这些时间表的过程决定了供水，影响动植物的分布，并调节诸如洪水和干旱之类的高频事件的发生。该项目提供了代表性不足和少数族裔大学生在研究中的参与，并参与研究计划，以增强其领导能力。对于来自AGEP计划的学生的指导是协调的，并提供了UCSC的“第一个毕业地质计划-Geokids”，并提供了K -12教育课“通信海洋科学”。该项目参加了由NSF资助的国家教育计划“科学日记”和“儿童科学挑战赛”（通过地球的脉搏，NPR）。 PI还正在开发基于询问的课程，讨论古环和古气候学的主题。