EAR-PF: Detecting dynamic topography in interglacial Caribbean sea level

12万年前的温暖时期是地球全球气候最后一次比现在温暖，也是地球在温暖的未来可能看起来像什么的一个例子。在此期间，冰盖比今天小，导致平均海平面上升。海平面升高的地质证据包括构成佛罗里达群岛的珊瑚礁化石，以及整个加勒比地区和其他地方的类似特征。然而，这些地质记录表明，在这个温暖时期达到的最高海平面在世界各地是不同的。本研究旨在揭示这一时期海平面空间变化的各种影响因素。特别是，这项研究旨在确定地幔动态地形的影响，地球表面的地幔流动，对海平面的变形。通过更好地限制影响海平面的不同因素，这项研究将提高科学家对海平面变化的空间模式和冰盖对气候变化的敏感性的理解。这些进展将帮助科学家更好地预测气候变暖下的未来海平面。更广泛地说，这项研究将阐明南佛罗里达景观在12万年前温暖时期在浅海条件下形成的条件，以及它面临的持续和未来海平面上升的风险。该项目包括一个教育部分，以提高人们对地质历史和未来气候风险的认识，人口稠密的迈阿密地区，这项研究将被执行。海平面上升是一个全球紧迫的问题，但存在很大的不确定性与冰盖变暖的敏感性和空间可变的海平面变化的模式。这两个组成部分都可能受到过去海平面变化研究的约束。该项目旨在限制地幔动态地形对大加勒比区域在最后一次间冰期（约12万年前）期间海平面时空变化的影响。这是最近一次全球平均海平面高于现在，因此可以让科学家了解海平面在未来变暖的地球上可能如何变化。然而，过去和未来的海平面的影响，空间可变的固体地球变形，包括动态地形造成的地幔流。为了提高对这一过程的科学认识，本项目将把联合收割机数值模拟与地质海平面数据相结合。该项目的第一个组成部分是开发高分辨率的地幔流动全球模型，预测整个大加勒比区域动态地形的变化幅度和速度。第二个组成部分是汇编一个关于间冰期海平面指标的区域综合数据集，以揭示整个区域海平面的空间趋势。通过将这些数据与建模结果和已发表的冰川均衡调整预测相结合，该项目将估计动态地形变化及其对整个区域海平面空间变化和末次间冰期全球平均海平面的贡献。这些结果将提高科学家对海平面变化的空间变异性以及冰盖和全球平均海平面对气候变化的敏感性的认识。该项目还包括一项公众教育活动，以提高人们对人口稠密的南佛罗里达景观的海洋起源的认识，该景观形成于最后一次间冰期，以及该地区海平面上升的危害。该奖项反映了NSF的法定使命，并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，被认为值得支持。

The warm period ~120,000 years ago was the last time that Earth’s global climate was warmer than the present and is an example of what the Earth might look like in a warmer future. During this time, ice sheets were smaller than today, causing higher mean sea levels. Geologic evidence for higher sea levels includes the fossil coral reefs that make up the Florida Keys, and similar features throughout the Caribbean region and elsewhere. However, these geologic records indicate that the maximum sea level reached during this warm period was different in different places around the world. This study aims to unravel the various contributing factors to the spatial variability in sea level during this time. In particular, this research seeks to identify the influence of mantle dynamic topography, the deformation of Earth’s surface by the flow of Earth’s mantle, on sea level. By better constraining the different factors affecting sea level, this research will improve scientists’ understanding of spatial patterns of sea-level change and the sensitivity of ice sheets to climate change. These advances will help scientists better predict future sea levels under a warming climate. More broadly, this research will illuminate the conditions under which the South Florida landscape was formed under shallow marine conditions during the warm period 120,000 years ago, and the risks it faces from ongoing and future sea-level rise. This project includes an educational component to raise awareness of the geologic history and future climate risks the densely populated Miami region where this research will be performed.Sea-level rise is a globally pressing concern, but substantial uncertainty exists with both the sensitivity of ice sheets to warming and in the patterns of spatially variable sea-level change. Both components can be constrained by the study of past sea-level change. This project seeks to constrain the influence of mantle dynamic topography on spatio-temporal variations in sea level in the greater Caribbean region during the last interglacial period, ~120,000 years ago. This was the most recent time that global mean sea level was higher than present, and thus can inform scientists’ understanding of how sea level might change on a future warmer earth. However, past and future sea level are influenced by spatially variable solid earth deformation, including the dynamic topography resulting from mantle flow. To improve scientific understanding of this process, this project will combine numerical modeling with geologic sea-level data. The first component of the project is the development of high-resolution global models of mantle flow, which predict the magnitude and rate of change of dynamic topography across the greater Caribbean region. The second component is the compilation of a regionally comprehensive dataset of interglacial sea level indicators to reveal spatial trends in sea level across the region. By combining these data with modeling results and published glacial isostatic adjustment predictions in a statistical inversion, this project will estimate the dynamic topography change and its contribution to spatial variability in sea level across the region and global mean sea level at the last interglacial. These results will improve scientists’ understanding both of spatial variability in sea-level change and of the sensitivity of ice sheets and global mean sea level to changes in climate. This project also includes a public education campaign to increase awareness of the marine origins of the populous South Florida landscape, formed during the last interglacial period, and of the hazards of sea-level rise in the region.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.