Collaborative Research: How Robust Are Common-Era Sea-Level Reconstructions?

海平面上升是气候变化最具挑战性的方面之一。为了对未来海平面估计的预测有信心，重要的是要清楚地了解海平面在过去是如何以及为什么自然变化的。该项目将收集现场数据并进行计算机模拟，以提高我们对共同时代(过去约2000年)控制平均海平面的主要因素的理解。例如，风和洋流的变化，水温的变化，以及由于冰或沉积物的重量去除而引起的陆地表面的反弹，都有助于改变任何地方的海平面记录。该项目将根据过去对这些因素的估计误差，审查海平面重建过程中的不确定性的来源和性质。该项目不仅将帮助科学家提高我们对海平面变化原因的理解，还将通过提供更好的模型来预测未来的海平面变化，从而帮助沿海规划者。该项目还将支持三名年轻科学家，加深他们的野外、实验室和建模技能。了解共同时代的海平面对于确定与人为气候变化有关的现代海平面上升的独特性、确定海平面与自然气候变异性之间的联系以及培训未来海平面上升的半经验模型至关重要。过去的研究使用代理记录估计了共同时代的全球平均海平面。这些估计在前工业时代的全球平均海平面变化方面存在很大差异。要确定这些估计对从原始数据生成全球平均海平面时间序列所涉及的各种不确定性、假设和选择有多敏感，还有待确定。在野外、实验室和模型分析的基础上，详细研究了共生时代海平面重建的稳健性和重复性。目标包括：(1)确定高分辨率盐沼海平面重建的可重复性；(2)量化共同时代全球平均海平面模型估计的稳健性。成果将填补基本知识空白，促进对共同时代的理解，并导致更好地描述工业化前和工业化后海平面变化的趋势、模式和原因。通过记录过去海平面的时空变化，评估共同时代的相关变化率，并确定与海洋环流和气候的联系，该项目将有助于实现古气候变化视角(P2C2)计划的目标和科学目标。这一奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的学术价值和更广泛的影响评估标准，被认为是值得支持的。

Sea-level rise is one of the most challenging aspects of climate change. In order to be confident in predictions of future sea level estimates, it is important to clearly understand how and why sea level changed naturally in the past. This project will collect field data and perform computer modeling to improve our understanding of the main factors that control average sea level during the Common Era (past ~2,000 years). For example, changes in wind and ocean currents, water temperature, and the rebound of land surfaces caused by removing the weight of ice or sediments all contribute to changes in the record of sea level at any location. This project will examine the origin and nature of uncertainties that enter into sea level reconstructions based on errors in estimating each of these factors in the past. The project will not only help scientists improve our understanding of the causes of sea level changes, but it also will help coastal planners by providing better models for projecting sea-level changes into the future. The project will also support three young scientists, deepening their field, laboratory, and modeling skills.Understanding sea level during the Common Era is central to establishing the uniqueness of modern sea-level rise related to anthropogenic climate change, identifying links between sea level and natural climate variability, and training semi-empirical models of future sea-level rise. Past studies estimate global-mean sea level during the Common Era using proxy records. These estimates differ substantially in terms of global-mean sea-level variability during pre-industrial times. It remains to establish how sensitive these estimates are to various uncertainties, assumptions, and choices involved in producing global-mean sea-level time series from the raw data. A detailed study of the robustness and reproducibility of Common-Era sea-level reconstructions based on field, laboratory, and modeling analyses is proposed. Objectives include: (1) determine the reproducibility of high-resolution salt-marsh sea-level reconstructions; and (2) quantify the robustness of model estimates of Common-Era global-mean sea level. Outcomes will fill basic knowledge gaps, advancing understanding of the Common Era, and leading to better characterization of trends, patterns, and causes of pre- and post-industrial sea-level change. By documenting past spatiotemporal variability of sea level, evaluating associated rates of change during the Common Era, and identifying links to ocean circulation and climate, the project will contribute to achieving the goals and scientific objectives of the Paleo Perspectives on Climate Change (P2C2) program. Efforts will make progress towards the broader goals of sea-level research related to the sensitivity of ice sheets to climate change, the response of the solid Earth to redistribution of ice mass, and the assimilation of proxy records and instrumental observations within a coherent probabilistic framework.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.