CAREER: Deconvolution of marine oxygen isotopic variability with an Earth system model to constrain sea level across the Pliocene

该奖项全部或部分根据2021年美国救援计划法案（公法117-2）资助。该项目旨在限制上新世时期（530 - 260万年前）的海平面，以更好地了解冰盖的稳定性。由于二氧化碳浓度与现在相似，全球气温比工业化前高2-4°C，上新世为未来气候变化提供了一个很好的模拟。上新世的海平面可能更高，但仍然存在很大的不确定性，估计比现在高出0到50米。为了完善上新世海平面估计，这项研究使用了一系列地球系统模型模拟来重新解释过去的温度和冰量记录。该项目的地球系统模型数据将进入公共数据库，为教育和未来研究提供社区资源。该项目还将为高中生、本科生和研究生提供一系列教育活动，以培养下一代地球科学家。海洋氧同位素记录是我们了解过去气候的基础。然而，从海洋氧同位素记录中提取海洋温度、环流和海平面仍然很困难。跟踪水同位素的地球系统模型可以量化海洋同位素组成和温度对海洋氧同位素记录的贡献，因此可以提供过去海平面的估计。该项目将利用跟踪水同位素的地球系统模型，探索海洋氧同位素对上新世一系列轨道、二氧化碳和冰盖配置的响应。这些模拟将1）允许构建上新世气候模拟器，能够对海洋、大气和陆地的同位素变化进行短暂的全球重建，2）为动态冰盖模拟提供强迫，这将作为独立和补充评估过去的海平面和氧同位素变化，以及3）评估广泛的上新世代理网络的技能和灵敏度。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). The project aims to constrain sea level during the Pliocene Epoch (5.3 – 2.6 million years ago) in an effort to better understand ice sheet stability. With carbon dioxide concentration similar to present-day and global temperatures 2-4°C warmer than preindustrial, the Pliocene provides a good analog for future climate change. Sea level was likely higher during the Pliocene, but significant uncertainty remains, with estimates ranging from 0 to 50 meters above present-day. To refine Pliocene sea level estimates, this study uses a series of Earth system model simulations to reinterpret records of past temperature and ice volume. The Earth system model data from this project will go into a public database, providing a community resource for education and future research. This project will also produce a collection of educational activities for high school, undergraduate, and graduate students to foster the next generation of geoscientists. Marine oxygen isotope records have been fundamental to our understanding of past climates. However, extracting ocean temperature, circulation, and sea level from marine oxygen isotope records remains difficult. Earth system models that track water isotopologues can quantify the contributions from ocean isotopic composition and temperature to the marine oxygen isotope records, and therefore, can provide estimates of past sea level. This project will leverage an Earth system model that tracks water isotopologues to explore marine oxygen isotope responses to a suite of orbital, carbon dioxide, and ice sheet configurations of the Pliocene. These simulations will 1) allow for the construction of a Pliocene climate emulator capable of producing transient global reconstructions of isotopic changes of the ocean, atmosphere, and land, 2) provide forcings for dynamic ice sheet simulations, which will serve as an independent and complementary assessment of past sea level and oxygen isotope variability, and 3) evaluate the skill and sensitivity of the extensive Pliocene proxy network.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.