Reconstructing Earth Energy Imbalance

重建地球能量失衡

• 批准号: 2202526
• 负责人: Gregory Hakim
• 金额: $ 48.06万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2202526&HistoricalAwards=false
• 关键词: Reconstructing; Earth; Energy; Imbalance

The net energy balance at the top of Earth’s atmosphere is critical for many important problems in climate science (e.g., climate sensitivity to changing greenhouse gas concentrations and modes of interaction between the atmosphere and ocean). Despite this central role, Earth’s energy budget has only been well observed for about the past 20 years. This short period of direct observation leaves a limited sample for evaluating important questions about climate variability, especially for distinguishing between variability that is externally forced versus internal to the climate system. While these questions can be approached using climate models, paleoclimate proxies provide the only encoding of climate information before the instrumental era, and thus are essential for quantifying climate variability, and particularly Earth’s energy imbalance on interannual, decadal and longer timescales. This project proposes to reconstruct Earth’s energy budget for the past 1000 years using paleoclimate data assimilation (PDA) method. This approach combines information from paleoclimate proxies with the physical constraints of climate models to reconstruct climate fields that are not directly observed by the proxies. The proposed research takes advantages of recent numerical simulations and preliminary-proof-of concept calculations to achieve this reconstruction.Specifically, the researchers will use an offline PDA, where the stationary statistics of long climate model simulations are used to supply physical constraints, and online PDA, where computationally efficient emulators of the climate models add dynamical “memory” to the reconstructions from proxies at earlier times. The researchers aim to construct outgoing shortwave and longwave radiation at the top of the atmosphere, and storage in terms of ocean heat content. The reconstructions will then be used to address a hypothesis on the relationship between spatial patterns of sea-surface temperature variability and energy imbalance. This project will provide a proxy-constrained estimate of Earth’s energy imbalance, both in ocean heat content and in the top-of-atmosphere radiative imbalance. A hierarchy of validation experiments, using satellite measurements, instrumental measurements, and historical simulations will provide confidence bounds on these estimates. The proposed research directly addresses important open problems in climate science, including pre-industrial energy imbalance needed for climate sensitivity, and the contribution of patterns of Pacific temperature variability to the planetary energy imbalance. The potential Broader Impacts include a gridded data product synthesizing paleoclimate proxy and model data for the top-of-atmosphere energy imbalance. Such a gridded millennial scale reconstruction will be made publicly available to the wide paleoclimate community for a widespread climate research, including detection and attribution-studies. This work will support the scientific training and professional development of one graduate student at the University of Washington.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.

地球大气层顶部的净能量平衡对于气候科学中的许多重要问题（例如，气候对温室气体浓度变化的敏感性以及大气与海洋之间相互作用的模式）至关重要。尽管有这样的核心作用，地球的能量收支直到过去20年才被很好地观察到。这种短时间的直接观测为评估有关气候变率的重要问题留下了有限的样本，特别是在区分气候系统的外部强迫变率与内部变率方面。虽然这些问题可以通过气候模式来解决，但古气候代用物提供了仪器时代之前气候信息的唯一编码，因此对于量化气候变率，特别是年际、年代际和更长时间尺度上的地球能量不平衡至关重要。本项目拟利用古气候资料同化（PDA）方法重建地球近1000年的能量收支。该方法将古气候代用物的信息与气候模式的物理约束相结合，重建代用物没有直接观测到的气候场。该研究利用了最近的数值模拟和初步概念验证计算来实现这种重建。具体来说，研究人员将使用离线PDA，其中长期气候模型模拟的静态统计数据用于提供物理约束，以及在线PDA，其中计算效率高的气候模型模拟器为早期代理的重建添加动态“记忆”。研究人员的目标是在大气顶部建立短波和长波辐射，并根据海洋热含量进行储存。然后，这些重建将用于解决关于海洋表面温度变化的空间格局与能量不平衡之间关系的假设。这个项目将对地球的能量不平衡提供一个代理约束的估计，包括海洋热含量和大气顶部的辐射不平衡。使用卫星测量、仪器测量和历史模拟的验证实验层次结构将提供这些估计的置信范围。提出的研究直接解决了气候科学中重要的开放性问题，包括气候敏感性所需的工业化前能量不平衡，以及太平洋温度变化模式对地球能量不平衡的贡献。潜在的更广泛的影响包括综合古气候代理和大气顶部能量不平衡模式数据的网格化数据产品。这样的千年尺度网格重建将公开提供给广泛的古气候界，用于广泛的气候研究，包括探测和归因研究。这项工作将支持华盛顿大学一名研究生的科学训练和专业发展。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。