RAPID: Carbon Cycle-Climate Feedback Analysis in CMIP5 Models

这是由一封亲爱的同事来信(NSF 11-006)资助的16个快速反应(RAPID)项目之一，该信鼓励对为政府间气候变化专门委员会第五次评估报告(IPCC AR5)准备的气候模型模拟进行诊断分析。在这些项目中进行的研究有望导致更详细的模型相互比较，更好地理解稳健的模型行为，以及更好地理解和量化未来气候模拟中的不确定性。本项目将分析耦合模型对比项目(CMIP5)模型，重点关注耦合碳-气候反馈的强度。PI将分析最新的一套模型在模拟19-20世纪碳循环和气候的协变性以及预测未来变化方面的能力。将开展的主要任务是：(I)通过与观测结果的比较来评估模式模拟的真实性；(Ii)根据关键的观测约束建立标准来对模式进行分组；(Iii)分析预测的21世纪碳气候反馈的强度，与早期的结果进行比较，并从响应和反馈方面诊断结果；(Iv)使用中等复杂性的模式来进一步理解CMIP5模式的行为，例如对碳参数的敏感性。首席调查员还将对北极永久冻土和亚热带半干旱和森林地区等脆弱碳库进行区域重点分析。该项目的更广泛影响在于它支持IPCC AR5，该报告旨在向世界各地的决策者提供关于气候变化及其后果的信息。该项目将研究当前最先进的科学模型中的碳气候反馈。这项研究将深入了解当前模型中的不足之处，以及改进模型所需的关键观察和实验。这样的努力对于理解未来大气二氧化碳浓度、气溶胶辐射强迫和地球气候对温室气体增加的敏感性的轨迹至关重要。

This is one of 16 Rapid Response (RAPID) projects funded as the result of a Dear Colleague Letter (NSF 11-006) encouraging diagnostic analyses of climate model simulations prepared for the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). Research conducted in these projects is expected to lead to more detailed model intercomparisons, better understanding of robust model behaviors, and better understanding and quantification of uncertainty in future climate simulations.This project will analyze the Coupled Model Intercomparison Project (CMIP5) models with a focus on the strength of coupled carbon-climate feedback. The PI will analyze the ability of the latest suite of models, in simulating 19th -20th century co-variability in carbon cycle and climate, as well as projected future changes. The main tasks that will be undertaken are: (i) assessing the realism of the model simulations by comparison with observations; (ii) establishing criterion based on key observational constraints to group the models; (iii) analyzing the strength of carbon-climate feedbacks projected for the 21st century, comparing with earlier results and diagnosing the results in terms of response and feedback; (iv) using a model of intermediate complexity to further understand the CMIP5 model behaviors, such as sensitivity to carbon parameterizations. The principal investigator will also conduct regionally focused analysis for vulnerable carbon pools in such as the Arctic permafrost and subtropical semiarid and forested regions.The broader impact of the project lies in its support of the IPCC AR5, which is intended to provide information on climate change and its consequences to decision makers worldwide. This project will examine carbon-climate feedbacks in the current state-of-the-science models. The study will shed insights into both the deficiencies in current models as well as key observations and experiments needed to improve the models. Such an effort is critical to understanding the trajectory of future concentration of atmospheric CO2, aerosol radiative forcing and sensitivity of earth's climate to greenhouse gas increases.