Ocean carbon reservoirs and the air-sea flux of CO2 in a changing climate

大气中二氧化碳以前所未有的速度增加，及其对气候的潜在影响，刺激了数值气候和碳循环模式的重大发展和应用。这些模型正变得极其复杂，许多物理和地球化学模块耦合在复杂的四维集成中。此外，模型中的许多过程可能分辨率很差和/或参数化粗糙。这些模型的解释需要强大的和简化的诊断框架。在该项目中，马萨诸塞州理工学院的一个研究小组将开发和应用工具，绘制海洋碳泵和二氧化碳海气通量的物理/生物驱动因素的地图，并对其进行量化。 他们将使用这些工具来阐明和量化碳循环对气候变化响应的机制，方法是使用麻省理工学院中等复杂性地球系统模型（IGSM）以及可用的CMIP 5仔细分析一系列敏感性研究，IPCC气候和碳循环模拟和预测：（1）诊断框架将用于评估若干海洋碳泵（库）对模型和观测中海洋碳储存的贡献，并解释海气碳通量的区域驱动因素。 (2)与IGSM的模拟合奏将被用来探讨模型参数的关键不确定性如何影响模拟的海洋碳泵在前工业时代。 (3)Ensemble模拟将扩展到整个21世纪，另外还将探索几种人为排放情景下气候敏感性、气溶胶强迫和风型变化的不确定性。 (4)大型IGSM集合和诊断工具将被用作审查最先进的CMIP 5气候模型的气候/碳循环预测的背景，无论是在模拟当今还是未来的变化情景中。 这些工具不仅应有助于分析观测结果和项目模拟，而且还可作为解释所有IPCC级气候和碳模拟的框架。更广泛的影响：这项研究的主要影响是它对气候和碳循环模型应用于近期预测的重要性，这是IPCC进程的重要组成部分。拟议的研究将对模型得出的不确定性进行评估，这些不确定性可用于评估气候系统的当前和未来状态。它将提供一个框架，说明不断变化的物理环境如何影响下一个世纪的海洋碳泵和海气通量。所有的诊断工具和衍生产品将免费分发，以继续应用，以帮助解释日益复杂的耦合数值模拟的不断增长的库存。此外，拟议的工作将为博士后研究人员提供一个激励和跨学科的项目。

The unprecedented rate of increase in atmospheric carbon dioxide, and its potential impact on climate, has stimulated significant development and application of numerical climate and carbon-cycle models. Such models are becoming extremely complicated, with numerous physical and biogeochemical modules coupled in complex, four-dimensional integrations. Moreover many processes in models may be poorly resolved and/or crudely parameterized. The interpretation of these models requires robust and simplifying diagnostic frameworks. In this project, a research team at the Massachusetts Institute of Technology will develop and apply tools to map and quantify the ocean carbon pumps and the physical/biological drivers of the air-sea fluxes of carbon dioxide. They will use these tools to elucidate and quantify mechanisms underpinning the response of the carbon cycle to climate change, through careful analysis of an ensemble of sensitivity studies using the MIT Earth System Model of intermediate complexity (IGSM), as well as available CMIP5, IPCC climate and carbon cycle simulations and projections: (1) Diagnostic frameworks will be used to evaluate the contributions of several ocean carbon pumps (reservoirs) to ocean carbon storage in models and observations as well as to interpret regional drivers of air-sea carbon flux. (2) An ensemble of simulations with the IGSM will be used to explore how key uncertainties in model parameters affect simulations of the ocean carbon pumps in the pre-industrial era. (3) Ensemble simulations will be extended through the 21st Century, additionally exploring uncertainties in climate sensitivity, aerosol forcing and wind pattern changes under several anthropogenic emissions scenarios. (4) The large IGSM ensemble and diagnostic tools will be used as the context for examining climate/carbon cycle projections from state-of-the-art CMIP5 climate models, both in simulations of the present day and future change scenarios. These tools should be useful not only in the analysis of observations and for the project simulations, but also as a framework for the interpretation of all IPCC-class climate and carbon simulations. Broader Impacts: The key broader impact of this study is its significance for the application of climate and carbon cycle models to near-future projections, an important part of the IPCC process. The proposed study will provide an evaluation of model-derived uncertainties which can be used in assessments of current and future states of the climate system. It will provide a framework for elucidating how the changing physical environment may impact the ocean carbon pumps and air-sea fluxes over the next century. All of the diagnostic tools and derivative products will be distributed freely for continued application to assist in the interpretation of the growing inventory of increasingly complex coupled numerical simulations. In addition, the proposed work will provide a stimulating and interdisciplinary project for a post-doctoral researcher.