An energy budget framework to understand mechanisms of land-ocean warming contrast induced by increasing greenhouse gases Part Ⅰ: Near-equilibrium state
An energy budget framework to understand mechanisms of land-ocean warming contrast induced by increasing greenhouse gases Part Ⅰ: Near-equilibrium state
复制标题
用于理解温室气体增加引起的陆地-海洋变暖对比机制的能源预算框架第一部分：近平衡状态
DOI：
10.1175/jcli-d-21-0302.1
复制
发表时间：
2021
影响因子：
4.9
通讯作者：
M. Watanabe and M. Yoshimori
中科院分区：
文献类型：
--
作者：
Toda;M.;M. Watanabe and M. Yoshimori
模拟研究表明，地面空气温度（SAT）的增加，在大气中的CO2浓度的增加是在陆地上比在海洋上更大的响应。这种所谓的陆地-海洋变暖对比，定义为陆地平均SAT变化除以海洋平均SAT变化，是全球变暖的一个显著特征。陆地上的小热容量不太可能是唯一的原因，因为在CO2倍增实验的平衡状态下发现了陆地-海洋变暖的对比。已经提出了几种不同的机制来解释陆地-海洋变暖的对比，但尚未获得全面的理解。在本研究的第一部分中，我们提出了一个框架来诊断的基础上，在大气顶部的能量收支和大气，这使得有效辐射强迫（ERF），气候反馈，热容量和大气能量输送异常的贡献分解到CO2。使用这个框架，我们分析了SAT的响应突然CO2翻两番使用15耦合模型相互比较项目第6阶段（CMIP 6）地球系统模型。在近平衡状态（121-150年），ERF为1.49 ± 0.11，这主要是由海陆ERF和热容量的差异引起的。我们发现，ERF，反馈和能量传输异常的贡献往往相互抵消，导致一个小的模型间传播的单个组件相比，大的传播。在无热容贡献的平衡状态下，ERF和能量输送异常是影响CO2的主要因素，与平衡气候敏感性呈弱负相关。
Modeling studies have shown that the surface air temperature (SAT) increase in response to an increase in the atmospheric CO2concentration is larger over land than over ocean. This so-called land–ocean warming contrast,ϕ, defined as the land-mean SAT change divided by the ocean-mean SAT change, is a striking feature of global warming. Small heat capacity over land is unlikely to be the sole cause because the land–ocean warming contrast is found in the equilibrium state of CO2doubling experiments. Several different mechanisms have been proposed to explain the land–ocean warming contrast, but a comprehensive understanding has not yet been obtained. In Part I of this study, we propose a framework to diagnoseϕbased on energy budgets at the top of atmosphere and for the atmosphere, which enables the decomposition of contributions from effective radiative forcing (ERF), climate feedback, heat capacity, and atmospheric energy transport anomaly toϕ. Using this framework, we analyzed the SAT response to an abrupt CO2quadrupling using 15 Coupled Model Intercomparison Project phase 6 (CMIP6) Earth system models. In the near-equilibrium state (years 121–150),ϕis 1.49 ± 0.11, which is primarily induced by the land–ocean difference in ERF and heat capacity. We found that contributions from ERF, feedback, and energy transport anomaly tend to cancel each other, leading to a small intermodel spread ofϕcompared to the large spread of individual components. In the equilibrium state without heat capacity contribution, ERF and energy transport anomaly are the major contributors toϕ, which shows a weak negative correlation with the equilibrium climate sensitivity.