RAPID Collaborative Research: Ground Truthing Coral Proxy Reconstructions of ENSO by Observing the 2014-15 El Nino

RAPID 协作研究：通过观测 2014-15 厄尔尼诺现象对 ENSO 进行地面实况珊瑚代理重建

• 批准号: 1446930
• 负责人: Samantha Stevenson
• 金额: $ 7.3万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1446930&HistoricalAwards=false
• 关键词: RAPID; Collaborative; Research; Ground; Truthing

The El Nino/Southern Oscillation (ENSO) is the dominant source of inter-annual climate variability in the world and it impacts a variety of important economic sectors in the U.S. and around the world like fisheries, agriculture and water resource management. Thus, it is vital to understand how its properties (magnitude, rate of occurrence, duration) might change under future climates. State-of-the-art climate model projections show no agreement on the direction of future ENSO changes and instrumental records are too short to constrain the statistics of ENSO, making it imperative to use paleoclimate reconstructions to establish a long-term observational context for ENSO. Record of isotopic oxygen in corals collected in the central equatorial Pacific suggests that ENSO may strengthen in the future, but a major caveat remains: the physics of the ENSO influence on the properties of corals is poorly understood, as their chemical composition is affected by water exchange in the reef environment, as well as by precipitation. This project will collect in situ observations of physical conditions (temperature, salinity,and currents) and isotopic variations (in seawater, precipitation, and corals) during a rapidly approaching event: the El Nino expected during winter 2014-15. The proposed dataset will be used to validate ongoing modeling work, create a reanalysis of the 2014-15 El Nino event with the goal of improving the interpretation of reconstructed records of past El Ninos. A post-doctoral fellow will lead the project and in the process will expand her technical and scientific expertise.Tehcnical description: Paleoclimate information from coral isotopic oxygen (Oxygen 18) is a critical source of data on past climate variability, providing an observational baseline for projections of future changes to ENSO. However, ENSO affects Oxygen 18 through advective shifts, topographically-induced upwelling, and surface fluxes: this makes it extremely difficult to use Oxygen 18 records for quantitative comparisons with instrumental records or climate model output. An ongoing NSF-funded study using a newly developed, isotope-enabled version of the Regional Ocean Modeling System (isoROMS) has shown that the spatial scale of processes affecting Oxygen 18 may be quite small, as proxy collection sites lie in nearshore reef environments. Thus, obtaining additional in situ data is critical for validating the isoROMS result and improving dynamical understanding. The El Nino event expected during winter 2014-15 provides a unique opportunity to collect both in situ physical oceanographic information and isotopic measurements, which combined with the isoROMS work would provide the most complete and dynamically consistent characterization of the El Nino influence on proxy sites to date. The results would greatly advance interpretation of existing oxygen 18 records as well as climate model validation efforts. The proposed dataset would be a major asset for studies of coral paleoclimate reconstruction as well as climate model validation. This project is led by an early career female scientist, and will add an observational component to the research she is conducting under an NSF Ocean Sciences postdoctoral fellowship. Collaborations with colleagues from a range of disciplines will be facilitated by this study. Finally, the results will be used to develop a reanalysis of the 2014-15 El Nino event, which will be provided as a resource for the community.

El Nino/Southern振荡（ENSO）是世界际气候变异性的主要来源，它影响了美国和世界各地的各种重要经济部门，例如渔业，农业和水资源管理。因此，重要的是要了解其特性（幅度，发生率，持续时间）如何在未来的气候下发生变化。最先进的气候模型预测未显示对未来ENSO变化的方向的同意，工具记录太短了，无法限制ENSO的统计数据，因此必须使用古气候重建来为ENSO建立长期的观察环境。在赤道太平洋中部收集的珊瑚中的同位素氧记录表明，ENSO可能会在将来加强，但仍有一个重要的警告：ENSO对珊瑚性质的影响的物理学对珊瑚的特性的影响很差，因为它们的化学成分受到礁石环境中水交换的影响，以及受到沉淀的影响。该项目将在迅速接近的事件中收集物理条件（温度，盐度和电流）以及同位素变化（在海水，降水和珊瑚中）的原位观察：2014 - 15年冬季期望的El Nino预期。拟议的数据集将用于验证正在进行的建模工作，对2014-15 El Nino事件进行重新分析，以改善对过去El Ninos的重建记录的解释。博士后研究员将领导该项目，在此过程中将扩大她的技术和科学专业知识。但是，ENSO通过对流偏移，地形引起的上升流和表面通量影响氧18：这使得使用氧气18记录非常困难与工具记录或气候模型输出进行定量比较。一项正在进行的NSF资助的研究，使用新开发的，具有同位素的区域海洋建模系统（ISOROMS）的版本表明，影响氧气18的过程的空间规模可能很小，因为代理收集站点位于近岸礁环境中。因此，获得额外的原位数据对于验证异形结果和改善动力学理解至关重要。 2014 - 15年冬季预期的El Nino事件为收集原位物理海洋学信息和同位素测量提供了独特的机会，与Isoroms工作相结合，这将提供对迄今为止El Nino对代理站点影响的最完整和动态一致的表征。结果将大大推动对现有氧气18记录以及气候模型验证工作的解释。提出的数据集将是研究珊瑚古气候重建以及气候模型验证的主要资产。该项目由早期职业女科学家领导，并将为她在NSF海洋科学博士后研究金的研究中增加观察性组成部分。本研究将促进与各种学科的同事的合作。最后，结果将用于开发2014 - 15年El Nino活动的重新分析，该活动将作为社区提供资源。