Collaborative Research: P2C2 - Reconstructing rates and sources of sea-level change over the last ~150 thousand years from a new coral database

合作研究：P2C2 - 从新的珊瑚数据库重建过去约 15 万年海平面变化的速率和来源

• 批准号: 1702684
• 负责人: Jerry Mitrovica
• 金额: $ 6.81万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-15 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1702684&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Reconstructing; rates

COLLABORATIVE RESEARCH: RECONSTRUCTING RATES AND SOURCES OF SEA LEVEL CHANGE OVER THE LAST ~150 THOUSAND YEARS FROM A NEW CORAL DATABASE Future sea level rise, driven by shrinking land ice and ocean warming, threatens coastal populations, economic activity, infrastructure, and ecosystems around the world. Data on past sea level positions are critical for understanding how sensitive sea level and ice sheets are to temperature change. Paleo-sea level records come from several different sources. For time periods older than about 4000 years, some of the records with the best vertical resolution and most precise ages come from coral reefs, which grow at distinctive elevation ranges with respect to mean sea level.During the Last Interglacial stage, about 125,000 years ago, global average sea-surface temperature peaked around its current level, while analyses of corals and other proxies indicate global mean sea level peaked about 6-9 m higher than today. This magnitude of sea level rise - implying considerably smaller ice sheets in Greenland and West Antarctica - hints at the long-term commitment current warming has imparted to future sea level rise. The researchers in this project will use the coral sea level database to better understand rates of sea level and ice-sheet change over time, and how these rates relate to changes in the global climate. The knowledge gained will contribute to work by this team and others in the research community on future sea level projections. The project will provide a graduate student and a postdoctoral researcher with interdisciplinary training in oceanography, geology, geophysics and statistics. It will also synthesize a global reconstruction of sea-level over the last 150,000 years, and associated numerical methods for producing this reconstruction, that can be broadly used by the research community. This project focuses on four basic questions: (1) How much did global mean sea level vary over time, and how do local, relative sea levels vary in space, over this time period? (2) How fast did global mean sea level change during the last 150,000 years, and what was the relationship between changes in sea level and changes in temperature? (3) Can the spatial patterns of sea level change be used to separate the contributions of different ice sheets to global mean sea level change? (4) How does global mean sea level reconstructed using corals compare to other continuous records of sea level and climate change? To address these questions, the researchers will: (1) develop emulators of geophysical models of glacio-isostatic adjustment and mantle dynamic topography in order to estimate the contribution of different ice sheets to sea level change, (2) refine the history of seawater uranium isotope compositions that are important to interpreting accurate ages from U-Th-dated corals, and (3) incorporate ecological data about the relationship between coral growth position and sea level into a spatio-temporal statistical framework that links together the coral database and the geophysical models. The application of these techniques to the coral database for the last 150,000 years will provide a uniquely high-precision, continuous record of global mean sea level variability over this time period. This reconstruction will enable a more precise estimate of the magnitude of global mean sea level variability and rates of global mean sea level change, and should allow discrimination between global mean sea level contributions from North American and Arctic sources and those from Antarctic sources. These reconstructions will provide data with which to test the ice sheet models used to project future changes in addition to supporting the career development of a postdoctoral scholar and the training of a Ph.D. student.

合作研究：根据新的珊瑚数据库重建过去约 15 万年海平面变化的速率和来源 陆地冰面积缩小和海洋变暖将导致未来海平面上升，威胁到沿海人口、经济活动、基础设施和周围的生态系统世界。有关过去海平面位置的数据对于了解海平面和冰盖对温度变化的敏感程度至关重要。古海平面记录有几个不同的来源。对于大约 4000 年之前的时期，一些具有最佳垂直分辨率和最精确年龄的记录来自珊瑚礁，这些珊瑚礁相对于平均海平面的海拔范围不同。在末次间冰期，大约 125,000 年前，全球平均海面温度在当前水平附近达到峰值，而对珊瑚和其他替代物的分析表明，全球平均海平面峰值比今天高出约 6-9 m。海平面上升的幅度如此之大——意味着格陵兰岛和西南极洲的冰盖要小得多——暗示了当前变暖对未来海平面上升的长期影响。该项目的研究人员将使用珊瑚海平面数据库来更好地了解海平面和冰盖随时间变化的速率，以及这些速率与全球气候变化的关系。所获得的知识将有助于该团队和研究界其他人对未来海平面预测的工作。该项目将为一名研究生和一名博士后研究员提供海洋学、地质学、地球物理学和统计学的跨学科培训。它还将综合过去 15 万年的全球海平面重建，以及用于进行这种重建的相关数值方法，可供研究界广泛使用。该项目重点关注四个基本问题：（1）在这段时间内，全球平均海平面随时间变化了多少，以及当地相对海平面在空间上如何变化？ （2）过去15万年全球平均海平面变化有多快，海平面变化与气温变化之间有何关系？ （3）能否利用海平面变化的空间格局来区分不同冰盖对全球平均海平面变化的贡献？ (4) 使用珊瑚重建的全球平均海平面与其他海平面和气候变化的连续记录相比如何？为了解决这些问题，研究人员将：（1）开发冰川均衡调整和地幔动态地形的地球物理模型模拟器，以估计不同冰盖对海平面变化的贡献，（2）完善海水铀的历史对解释 U-Th 定年珊瑚的准确年龄非常重要的同位素组成，以及（3）将有关珊瑚生长位置与海平面之间关系的生态数据纳入将珊瑚数据库链接在一起的时空统计框架中和地球物理模型。将这些技术应用于过去 15 万年的珊瑚数据库将为这一时期的全球平均海平面变化提供独特的高精度、连续记录。这种重建将能够更精确地估计全球平均海平面变化的幅度和全球平均海平面变化的速度，并应能够区分北美和北极来源与南极来源对全球平均海平面的贡献。除了支持博士后学者的职业发展和博士生的培训之外，这些重建还将提供数据来测试用于预测未来变化的冰盖模型。学生。