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

海平面上升是气候变化中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，清楚地了解过去海平面如何以及为什么自然变化是很重要的。该项目将收集野外数据，并进行计算机模拟，以提高我们对控制普通时代（过去~ 2000年）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重量的消失而引起的陆地表面的反弹，都有助于任何地点海平面记录的变化。本项目将根据过去估计这些因素的误差，研究进入海平面重建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，而且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。该项目还将支持三位年轻科学家，深化他们的领域、实验室和建模技能。了解公元时期的海平面对于确立与人为气候变化相关的现代海平面上升的独特性、确定海平面与自然气候变率之间的联系以及训练未来海平面上升的半经验模式至关重要。过去的研究使用代理记录估计了平代时期的全球平均海平面。这些估计在工业化前时期的全球平均海平面变率方面存在很大差异。这些估计对于从原始数据中产生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。提出了基于野外、实验室和模型分析的普通时代海平面重建的鲁棒性和可重复性的详细研究。目标包括：(1)确定高分辨率盐沼海平面重建的可重复性；(2)量化模型估计的Common-Era全球平均海平面的稳健性。研究结果将填补基本知识空白，促进对“共同纪元”的理解，并有助于更好地描述工业化前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“普通时代”期间的相关变化率，并确定与海洋环流和气候的联系，该项目将有助于实现“古气候变化展望”（P2C2）计划的目标和科学目标。努力将朝着与冰盖对气候变化的敏感性、固体地球对冰块重新分布的反应以及在连贯的概率框架内同化代理记录和仪器观测等有关的海平面研究的更广泛目标取得进展。该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。

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.