Collaborative Research: Climate Variability and Change in the U.S. GLOBEC Regions as Simulated by the IPCC Climate Models: Ecosystem Implications

大量文献表明，生态系统动力学受到大尺度气候变化的强烈影响。气候影响海洋生物过程的一个主要方式是通过风驱动的海洋环流变化，这既受自然变化的影响，也受人类活动引起的变化的影响。为支持政府间气候变化专门委员会(IPCC)评估报告4(AR4)，用23个最先进的气候模型进行的模拟是研究气候变化的主要手段。IPCC-AR4模拟包括固定外部(太阳、火山、温室气体)强迫(控制模拟)的运行，以及根据观察到的20世纪记录(20世纪模拟)或根据不同的气候变化情景规定外部强迫的模拟。这些气候综合是全球性的，在每个模型网格点提供了大量变量的完整信息，包括那些与海洋生态系统相关的变量。IPCC-AR4模拟的结果将被用于研究三个GLOBEC区域(东北太平洋、西北大西洋和南大洋)的气候变异性和变化，重点关注以下问题：1.当代气候模型是否表明大尺度低频风强迫变化与GLOBEC研究区域的海洋环流变化之间的联系类似于人们认为存在于自然界的那些区域？IPCC-AR4多模式集合能否以更大的统计可信度扩展观测记录和检验气候环流联系的假设？2.基于最可靠的气候模式，气候对21世纪和22世纪区域过程变化的影响将达到什么程度？3.能否开发和使用统计降尺度方法来将区域(生态系统)尺度上的变化与大尺度气候强迫联系起来？能否确定更适合于统计缩小尺度的特定参数？第一个问题将通过分析控制和20世纪的模拟来解决，而下个世纪气候对区域过程的影响的预测将使用情景模拟来检验。现有的数据以及区域模式在不同分辨率下的输出将被用来评估统计缩减的可行性。这项研究将增进对不同区域生态系统动力学重要的大尺度气候强迫和物理过程之间的联系的理解。气候模型的全球性使在不同地理区域内和不同地理区域之间建立联系成为可能。因此，这项研究的结果支持GLOBEC计划的泛区域综合阶段。本研究有可能提高预测自然和/或人为引起的气候变化引起的生态系统变化的能力。该项目的结果可以为区域生态系统研究提供一个大尺度强迫及其在气候变化中的演变的视角，以及区域模式的边界条件和强迫场。具体地说，该项目的一个关键方面将是提供IPPC模型模拟的结果，并指导如何将这些结果用于通过GLOBEC计划这一阶段资助的其他研究人员。这项研究的结果还将通过NOAA和研究人员大学的推广计划向初中生和高中生展示。

A large body of literature has shown that ecosystem dynamics is strongly influenced by large scale climate variations. A primary way by which climate can affect marine biological processes is through wind-driven changes of the ocean circulation, which are influenced by both natural and anthropogenically-induced variability. Simulations performed with 23 state-of-the-art climate models in support of the Intergovermental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) are the principle means for examining climate change. The IPCC-AR4 simulations include runs with fixed external (solar, volcanoes, greenhouse gases) forcing (control simulations), as well as simulations where external forcing is prescribed according to the observed 20th century record (20th century simulations) or according to different climate change scenarios. These climate integrations are global and provide complete information on a large number of variables, including those relevant for marine ecosystems, at each model grid point. The output from the IPCC-AR4 simulations will be used to examine climate variability and change in the three GLOBEC regions (northeast Pacific, northwest Atlantic, and Southern Ocean) focusing on the following questions:1. Does the present generation of climate models show connections between large-scale low-frequency wind forcing variations and ocean circulation changes in the three GLOBEC study areas similar to those that are believed to exist in nature? Can the IPCC-AR4 multi-model ensembles be used to extend the observational record and test hypotheses on the climate-circulation links with a larger statistical confidence?2. Based on the most reliable climate models, to what extent will the influence of climate upon regional processes change over the 21st and 22nd centuries?3. Can statistical downscaling methods be developed and used for relating variations at the regional (ecosystem) scale to large-scale climate forcing? Can specific parameters be identified that are more amenable to statistical downscaling?The first question will be addressed by analyzing the control and 20th century simulations, while projections of the influence of climate on regional processes in the next century will be examined using the scenario simulations. Available data, as well as output from a regional model at different resolutions will be used to assess the feasibility of statistical downscaling.This study will improve understanding of the links between large-scale climate forcing and physical processes important for ecosystem dynamics in different regions. The global nature of climate models enables a consistent means of establishing connections within and between different geographical regions. Thus, results from this study support the pan-regional synthesis phase of the GLOBEC program.The present study has the potential to enhance the ability to predict ecosystem changes due to natural and/or anthropogenically induced climate variations. Results from this project can support regional ecosystem studies by providing a perspective of the large-scale forcing and its evolution in a changing climate, as well as boundary condition and forcing fields for regional models. Specifically, a key aspect of this project will be to provide output from the IPPC model simulations and guidance in how to use the output to other researchers funded through this phase of the GLOBEC program. Results from this study will also be presented to middle and high school students through the outreach programs at NOAA and at the investigators' Universities.