Collaborative Research: EaSM-3: Modeling, Understanding, and Prediction of the Decadal Variability of Productive Eastern Boundary Coastal Upwelling Regions

四个主要的东部边界上升流系统（EBUS）区域，即美国西海岸，洪堡洋流，加那利洋流和本格拉洋流，是地球上一些最具生产力的海洋生态系统的宿主。这四种类型还具有年际到年代际的大变率，以及通过沿岸风、上升流、云和环流尺度洋流的系统变化对气候变化的脆弱性。不幸的是，这些关键环境在未来几十年的演变得到的关注相对较少。部分原因是它们的基本特征（由当地地形和上升流带形成的沿岸风和云）只有几十公里宽，目前的气候模式无法很好地解决。此外，尺度小于模式分辨率的过程调解了关键生态系统属性与物理系统之间的关系，使得仅基于模式输出就很难理解物理系统变化对海洋生态系统的影响。在这个项目中，研究小组将通过开展一套前所未有的高分辨率区域地球系统模型模拟来解决这一差距。该项目的结果将是全面了解气候变化的后果及其与未来几十年所有四个EBUS地区的年代际变率的相互作用。由一名气候科学家、两名海洋学家、一名海洋生物地球化学家和一名软件工程师组成的跨学科团队将培训两名研究生。该项目将为进一步研究气候对EBUS地区上层营养水平的影响和鱼类种群预测奠定基础。此外，地球系统模型开发工作将为科学界研究海洋生态系统对气候变率和变化的高营养层响应奠定基础。海洋生态系统的变化对自然资源管理具有深远的影响，预计该项目将引起利益相关者和公众的极大兴趣。在一位环境传播专家的帮助下，该小组将制定并执行一项外联工作，其中包括确定和协调美国西海岸EBUS的利益相关者。将组织利益相关者研讨会，项目团队将在研讨会上展示他们的研究成果，利益相关者将向项目团队展示信息需求。研讨会的一项成果将是一份白皮书，概述在气候变化背景下海洋保护和管理的研究需求和下一步步骤。本研究的重点是四个东界上升流系统的未来演变。三个相互关联的研究主题是：(1)区域尺度上的海陆空相互作用；(2)EBUS区域的气候变化信号；(3)气候对海洋生态系统的控制。将进行一套高分辨率区域地球系统模式模拟。它们包括：(1)对所有四个EBUS区域近期变化的历史重建。这些再分析驱动的模拟将用于根据现有观测验证区域模式，并表征区域物理和生态系统状态的实质性变化。所有的实验将首先在美国西海岸和洪堡EBUS地区进行，然后将吸取的经验教训用于其他两个主要上升流系统的相同系列实验。(2)所有EBUS区域的世纪中期未来气候模拟。这些由全球气候模式（GCM）输出驱动的模拟将用于量化和了解由于人为强迫造成的物理和生态系统变化。它们还将与历史重建一起进行分析，以量化相对于该地区自然变率的人为信号的重要性，并检测最近的人为信号。为了最大限度地提高与十年预测的相关性，未来的气候实验将强调21世纪中期的时间框架。然而，我们也将进行一个以世纪末为重点的实验，以分析更极端的气候变化信号。(3)在选定的EBUS区域进行工艺评价仿真。这些也是重新分析驱动的，但是禁用了关键流程。这些实验将允许对形成可变性和变化的关键过程进行量化和理解。EBUS区域将相互比较，以了解驱动上升流变异性的过程和相关的生物地球化学反应。主要的生态系统动力学将包括：对上升流和温度的幅度和季节性的控制；对生产力规模和季节性的控制；缺氧强度和空间尺度的控制及其与循环和生产力的关系。

The four main Eastern Boundary Upwelling Systems (EBUS) regions, i.e., the U.S. West Coast, the Humboldt Current, the Canary Current, and Benguela Current, are host to some of the most productive marine ecosystems on the planet. All four are also characterized by large inter-annual to inter-decadal variability and vulnerability to climate change through systematic changes in alongshore winds, upwelling, cloud, and gyre-scale ocean currents. Unfortunately, the evolution of these critical environments over the coming decades has received comparatively little attention. This is partly because their essential characteristics (alongshore winds and cloud shaped by local topography and upwelling ribbons) are only tens of km in width and are not well-resolved by current climate models. In addition, processes smaller in scale than the model resolution mediate the relationship between key ecosystem properties and the physical system, making it very difficult to understand consequences of changes in the physical system for marine ecosystems based on model output alone. In this project the team of investigators will address this gap by undertaking an unprecedented suite of high-resolution regional earth system model simulations. The result of this project will be a comprehensive understanding of the consequences of climate change and its interplay with decadal variability over the coming decades for all four EBUS regions. Members of a cross-disciplinary team consisting of a climate scientist, two oceanographers, a marine biogeochemist and a software engineer will train two graduate students. The project will lay essential groundwork for further study of climate impacts on upper trophic levels and prediction of fish populations in EBUS regions. Moreover, the earth system model development work will lay the groundwork for the scientific community to study higher-trophic-level response of marine ecosystems to climate variability and change. Marine ecosystem variability has profound implications for natural resource management, and it is anticipated that this project will be of great interest to stakeholders and the general public. With the help of an environmental communications expert, the team will develop and execute an outreach effort that includes identification and coordination of stakeholders for the U.S. West Coast EBUS. A stakeholder workshop will be organized where the project team will present their research, and stakeholders will present information needs to the project team. An outcome of the workshop will be a white paper outlining research needs and next steps for marine conservation and management in the context of a changing climate. This project is focused on the future evolution of the four Eastern Boundary Upwelling Systems (EBUS). Three interconnected research themes will be pursued: (1) Air-sea-land interaction at the regional scale, (2) Climate change signals in EBUS regions, and (3) Climate controls on marine ecosystems. A suite of high-resolution regional earth system model simulations will be undertaken. They involve: (1) Historical reconstructions of the variations of the recent past in all four EBUS regions. These reanalysis-driven simulations will be used to validate the regional model against available observations and characterize the substantial variability of the regions' physical and ecosystem states. All sets of experiments will be performed for the U.S. West Coast and Humboldt EBUS regions first, and then the lessons learned will be leveraged to perform the same series of experiments for the two other major upwelling systems. (2) Mid-century future climate simulations for all EBUS regions. These simulations, driven by global climate model (GCM) output, will be used to quantify and understand physical and ecosystem changes due to anthropogenic forcing. They will also be analyzed together with the historical reconstructions to quantify the importance of anthropogenic signals relative to the regions' natural variability, and detect anthropogenic signals in the recent past. To maximize relevance to decadal prediction, the future climate experiments will emphasize the mid-21st-century time frame. However, we will also undertake one experiment focused on end-of-century to have a more extreme climate change signal to analyze. (3) Process evaluation simulations in select EBUS regions. These are also reanalysis-driven, but with key processes disabled. These experiments will allow for a quantification and understanding of the key processes shaping variability and change. The EBUS regions will be compared to one another to understand processes driving upwelling variability and associated biogeochemical responses. The major ecosystem dynamics of interest will include: controls on magnitude and seasonality of upwelling and temperature; controls on magnitude and seasonality of productivity; controls on intensity and spatial scale of hypoxia, and its relationship to circulation and productivity.