NSFGEO-NERC: Wider Impacts of Subpolar nortH atlantic decadal variaBility on the OceaN and atmospherE (WISHBONE)

NSFGEO-NERC：北大西洋副极地年代际变化对海洋和大气的更广泛影响 (WISHBONE)

• 批准号: 2040020
• 负责人: Stephen Yeager
• 金额: $ 49.99万
• 依托单位: University Corporation For Atmospheric Res
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2040020&HistoricalAwards=false
• 关键词: NSFGEO; NERC; Wider; Impacts; Subpolar

This project is jointly funded by the National Science Foundation's Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with their own country. The Subpolar North Atlantic (SNA), which is the region of the Atlantic Ocean between 45N - 65N latitude, is a highly variable region. Surface temperatures and surface salinity here have varied on a range of timescales with those on decadal or longer being the dominant ones. This decadal timescale variability appears to form a key component of a larger climate mode, the Atlantic Multidecadal Variability, which has been linked to a broad range of important climate impacts, including rainfall in the North African and south Asian monsoons, floods and droughts over Europe and North America, and the number of hurricane formations. The SNA is also one of the most predictable places on Earth at decadal timescales, which suggests there is potential for improved predictions of regional climate and high-impact weather years ahead. However, the origins of this variability, and the processes controlling its impacts, are far from fully understood. There is significant evidence to suggest that anomalous heat loss from the subpolar North Atlantic Ocean to the atmosphere can instigate a cascade of changes across the North Atlantic basin in both the ocean and atmosphere. For example, changes in the SNA can change the strength of the ocean circulation to the south, affect the northward transport of heat and freshwater in the North Atlantic, and subsequently affect the upper ocean temperatures and salinity across the whole North Atlantic basin, and into the Arctic. Changes in the subpolar North Atlantic surface temperature are also thought to affect the atmospheric circulation (i.e., wind patterns) in both summer and winter. However, observational records are very short, and so there are significant problems with understanding causality, and considerable uncertainty about how well many of the important processes are represented in current climate models. This project (WISHBONE) will make use of new advanced climate simulations and forecast systems to improve our understanding of the impact of the subpolar North Atlantic on the wider North Atlantic basin. It will also test specific hypotheses related to understanding the specific role of heat loss over the subpolar North Atlantic in driving changes throughout the basin including the role of surface anomalies in driving wind patterns. The project will enhance international collaboration with the UK and science results would be of interest to the public in the US and the UK, as both regions are impacted by SNA variability. NCAR will engage in outreach activities to communicate key findings through public lectures, press releases, and university lectures amongst others. It is anticipated that this work will inform ongoing and future decadal prediction activities, such as those led by NCAR and the UK Met Office. The overarching objective of WISHBONE is to characterize the linkages between anomalous buoyancy forcing of the SNA and impacts on the wider North Atlantic coupled system on decadal timescales, and to determine the oceanic and atmospheric processes that control these impacts. WISHBONE will do this by focusing on the specific linkages and underlying processes. Hence, the specific objectives of the project are: 1) to determine and evaluate the oceanic pathways through which changes in the SNA impact on lower latitudes in the Atlantic basin; 2) to determine the impact of changes in the SNA on atmospheric circulation over the North Atlantic on a range of timescales, and to deduce the important processes involved; 3) to determine the oceanic and atmospheric pathways through which changes in the SNA impact on higher latitudes and the Arctic; 4) to assess how robust are the mechanisms and timescales in numerical simulations at different resolutions, and their consistency with observations; 5)to explore how the influence of the SNA is modified by anthropogenic forcing. The key time scale to be addressed is decadal, but in the context of interannual-to-centennial changes in the SNA. The primary hypothesis is that buoyancy forcing over the SNA is the primary controller of Atlantic Decadal-to-Multidecadal coupled variability due to its key role in shaping the Thermohaline Circulation (THC) across the North Atlantic basin and, subsequently, upper ocean changes that result in an atmospheric response. Specific hypotheses include: 1) subsurface density anomalies in the SNA propagate down the western boundary and affect the AMOC at lower latitudes and the Gulf Stream Extension (GSE); 2) SNA SSTs force changes in the speed and/or latitude of the atmospheric eddy-driven jet in summer and winter, contributing to decadal jet variability; 3) subsurface density anomalies in the SNA are a key ingredient for successful predictions of major changes in the SNA (e.g. the mid-1990s warming), and associated changes in phase of the AMV.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.

该项目由国家科学基金会地球科学局（NSF/GEO）和英国国家环境研究委员会（NERC）共同资助，并通过NSF/GEO-GEO-NERC领导机构协议。该协议允许该机构提交和同行评审的一项联合提案，其调查员的预算比例最大。成功确定裁决后，每个机构为预算的比例和与自己国家相关的调查人员提供了资金。北大西洋（SNA）是一个高度可变的区域。这里的表面温度和表面盐度在一系列时间尺度上有所不同，而年龄段或更长的时间尺度则是主要的。这种十年时间尺度的可变性似乎构成了较大气候模式的关键组成部分，即大西洋多年代变化，这与广泛的重要气候影响有关，包括北非和南亚季风，洪水和欧洲和北美的洪水和干旱，以及呼吸道形态的数量。 SNA也是十年时间尺度上地球上最可预测的地方之一，这表明有可能改善未来地区气候和高影响力天气的预测。但是，这种可变性的起源以及控制其影响的过程远非完全理解。有大量的证据表明，从北大西洋下极到大气的异常热量损失可以激发海洋和大气中北大西洋盆地的一系列变化。例如，SNA的变化可以改变海洋循环的强度向南，影响北大西洋上的热和淡水的北部运输，然后影响整个北大西洋盆地的海洋温度和盐度，并进入北极地区。夏季和冬季，北大西洋表面温度的变化也被认为会影响大气循环（即风模式）。但是，观察性记录非常短，因此理解因果关系存在重大问题，并且关于当前气候模型中许多重要过程的表现如何。该项目（Wishbone）将利用新的高级气候模拟和预测系统，以提高我们对北大西洋亚北大西洋对北大西洋盆地的影响的理解。它还将检验与了解北大西洋亚北大西洋上热量损失在整个盆地变化中的特定作用有关的特定假设，包括表面异常在驱动风模式中的作用。该项目将增强与英国的国际合作，科学成果将引起美国和英国公众的关注，因为这两个地区都受SNA变异性的影响。 NCAR将通过公开讲座，新闻稿和大学演讲进行外展活动，以传达关键发现。预计这项工作将为正在进行的和未来的十年预测活动提供信息，例如由NCAR和英国大都会办公室领导的活动。叉骨的总体目标是表征SNA异常浮力强迫和对北大西洋耦合系统的影响之间的联系，并确定控制这些影响的海洋和大气过程。 Wishbone将通过关注特定的链接和基础过程来做到这一点。因此，项目的具体目标是：1）确定和评估SNA变化对大西洋盆地较低纬度的变化的海洋途径； 2）确定SNA变化对北大西洋大气循环的影响，并推断涉及的重要过程； 3）确定海洋和大气途径，通过这些途径，SNA的变化会影响更高的纬度和北极； 4）评估不同分辨率的数值模拟中的机制和时间表以及它们与观察的一致性的稳健性； 5）探索如何通过人为强迫来改变SNA的影响。要解决的关键时间尺度是十年的，但是在SNA的年际变化的背景下。主要的假设是，SNA上的浮力是大西洋十年到多摄氏度耦合的主要控制器，这是由于其在塑造北大西洋盆地的热盐循环（THC）中的关键作用，以及随后在大气响应导致大气变化的高层海洋变化。特定的假设包括：1）SNA中的地下密度异常在西部边界传播，并在较低纬度和海湾流延伸（GSE）下影响AMOC； 2）SNA SSTS力在夏季和冬季变化大气涡流喷气机的速度和/或纬度，导致衰老的喷气式变异性； 3）SNA中的地下密度异常是成功预测SNA重大变化（例如1990年代中期变暖）的关键要素，并且相关的AMV期相关的变化。该奖项反映了NSF的法定任务，并通过使用基金会的知识优点和广泛的影响来评估NSF的法定任务，并被视为值得通过评估来进行评估。

项目成果

Quantification of the Arctic Sea Ice‐Driven Atmospheric Circulation Variability in Coordinated Large Ensemble Simulations

• DOI: 10.1029/2019gl085397
• 发表时间: 2020-01
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Yu‐Chiao Liang;Young‐Oh Kwon;C. Frankignoul;G. Danabasoglu;S. Yeager;A. Cherchi;Yongqi Gao;G. Gastineau;R. Ghosh;D. Matei;J. Mecking;D. Peano;L. Suo;T. Tian