CAREER: Contextualizing recent extreme El Nino events over the late Holocene using trace element paleothermometry in tropical Pacific corals

该项目将在热带太平洋制作基于珊瑚的海表面温度重建。这些记录将记录过去3000年来厄尔尼诺-南方涛动(ENSO)的气候现象。今天，ENSO每隔几年就会推动全球天气模式的变化。它起源于热带太平洋和大气层，可能产生严重和深远的影响，影响数十亿人的自然环境和生活。过去几十年发生的一系列极端厄尔尼诺事件表明，大气中温室气体的增加可能正在导致ENSO事件加剧。然而，在一个变暖的世界中，ENSO可能会如何变化还不是很清楚。目前，由于仪器海洋表面温度记录的持续时间较短，在理解ENSO方面的进展受到限制。使用古气候代理数据的方法提供了一种方法，可以产生仪器时代之前的温度估计。然而，这些更长的替代温度记录依赖于珊瑚记录的稀疏网络。该项目将通过从中太平洋和东太平洋产生约40个新的长达数十年的珊瑚温度记录来缩小这一数据差距。该项目的教育和外联活动包括努力从地球科学代表性不足的群体中招聘和留住本科生，并加强佛罗里达州立大学本科生课程中的主动学习。它们还包括开发跨学科的研究生研究机会，并努力提高佛罗里达州北部高中的科学素养。该项目包括每年四年的研究生支持和对本科生研究人员的支持。该项目将在过去3000年产生40个新的定量温度记录，这些记录来自赤道太平洋的关键地区，横跨暖池的东部边缘到寒冷的舌头的核心。总体重建方法将使用比过去传统使用的更小、更广泛的珊瑚档案--珊瑚碎石--，测量将结合传统的锶/钙测量和较新的锶-铀技术。将使用严格的成岩作用筛选工具，包括微尺度分析，从化石记录中提取可靠的气候信息。这些重建将对赤道太平洋海温在季节性到千年时间尺度上的演变提供前所未有的数量限制，包括表征自工业时代以来相对于地球前3000年历史的极端ENSO事件的统计数据是否以及如何发生变化。该项目的教育目标将扩大研究的范围和影响，同时解决地球科学教育方面的突出需求。这些教育目标侧重于为进入科学工作大军的研究生和博士后扩大职业发展机会、技能建设、多样性和领导力培训。该项目还将把研究与社区需求和国际实地教育结合起来。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will produce coral-based sea surface temperature reconstructions in the tropical Pacific Ocean. These records will document the El Niño-Southern Oscillation (ENSO) climate phenomenon during the last 3000 years. Today, ENSO drives changes in weather patterns around the globe every few years. It originates in the tropical Pacific Ocean and atmosphere and can have severe and far-reaching impacts that affect the natural environment and the lives of billions of people. A series of extreme El Niño events over the last several decades suggests that rising atmospheric greenhouse gases may be causing ENSO events to intensify. However, how ENSO may change in a warmer world is not well known. Advances in understanding ENSO are currently limited by the short duration of instrumental sea surface temperature records. Approaches that use paleoclimate proxy data provide a way to produce temperature estimates from before the instrumental era. However, those longer proxy temperature records rely on sparse networks of coral-based records. This project will reduce that data gap by producing ~40 new decades-long coral-based temperature records from the central and eastern Pacific Ocean. The project’s education and outreach activities include efforts to recruit and retain undergraduates from groups underrepresented in the earth sciences and to strengthen active learning in the Florida State University undergraduate curriculum. They also include development of cross-disciplinary graduate research opportunities and efforts to improve science literacy in northern Florida high schools. The project includes four years of graduate student support and support for undergraduate researchers each year.The project will generate 40 new quantitative temperature records over the last 3,000 years from key regions of the equatorial Pacific Ocean spanning the eastern edge of the warm pool to the core of the cold tongue. An ensemble reconstruction approach will use smaller, more widely available coral archives than have traditionally been used in the past – coral rubble – and measurements will combine traditional Sr/Ca measurements with newer Sr-U techniques. Rigorous screening tools for diagenesis, including microscale analyses, will be employed to extract reliable climate information from the fossil records. The reconstructions will provide unprecedented quantitative constraints on the evolution of equatorial Pacific sea surface temperatures on seasonal to millennial time scales, including characterizing whether and how the statistics of extreme ENSO events have changed since the industrial era, relative to the prior 3,000 years of Earth history. The educational objectives of the project will increase the scope and impact of the research, while also addressing outstanding needs in geoscience education. These educational objectives focus on expanding professional development opportunities, skill building, and diversity and leadership training for graduate students and postdocs entering the scientific workforce. The project will also integrate research with community needs and education at international field sites.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.