What Can the Internal Variability of CMIP5 Models Tell Us about Their Climate Sensitivity?
What Can the Internal Variability of CMIP5 Models Tell Us about Their Climate Sensitivity?
复制标题
CMIP5 模型的内部变异性可以告诉我们什么有关其气候敏感性的信息？
DOI：
10.1175/jcli-d-17-0736.1
复制
发表时间：
2018
影响因子：
4.9
通讯作者：
Ken Takahashi
中科院分区：
文献类型：
--
作者：
N. Lutsko;Ken Takahashi
研究了气候模式的内部变率与其对外部强迫响应之间的关系。在CMIP 5存档的工业化前控制模拟中，在传出的大气层顶（TOA）能量通量和全球平均表面温度之间进行频率相关回归。结果表明，在近十年的频率上，地表温度与短波出射通量正交，而长波出射通量与温度呈线性关系，对温度扰动起负反馈作用。在较长的时间尺度上，出射的短波和长波通量都与温度呈线性关系，长波继续作为负反馈，短波作为温度变化的正反馈。除了不同的相位关系，这两个制度也可以看出，在估计的相干性和频率依赖的回归系数。在2.5 ~ 3年时间尺度上，天空总云量的频率相关回归系数与模式的平衡气候敏感度（ECS）有很强的相关性（r2 > 0.6），表明地球ECS存在潜在的“紧急约束”。然而，需要O（100）年的数据才能使这种关系变得稳健。一个简单的地球表面温度的变化及其与TOA通量的关系的模型是用来提供这些结果的物理解释。
The relationship between climate models’ internal variability and their response to external forcings is investigated. Frequency-dependent regressions are performed between the outgoing top-of-atmosphere (TOA) energy fluxes and the global-mean surface temperature in the preindustrial control simulations of the CMIP5 archive. Two distinct regimes are found. At subdecadal frequencies the surface temperature and the outgoing shortwave flux are in quadrature, while the outgoing longwave flux is linearly related to temperature and acts as a negative feedback on temperature perturbations. On longer time scales the outgoing shortwave and longwave fluxes are both linearly related to temperature, with the longwave continuing to act as a negative feedback and the shortwave acting as a positive feedback on temperature variability. In addition to the different phase relationships, the two regimes can also be seen in estimates of the coherence and of the frequency-dependent regression coefficients. The frequency-dependent regression coefficients for the total cloudy-sky flux on time scales of 2.5 to 3 years are found to be strongly ( r2 > 0.6) related to the models’ equilibrium climate sensitivities (ECSs), suggesting a potential “emergent constraint” for Earth’s ECS. However, O(100) years of data are required for this relationship to become robust. A simple model for Earth’s surface temperature variability and its relationship to the TOA fluxes is used to provide a physical interpretation of these results.
影响因子：
4.9
作者：
Lloyd, James;Guilyardi, Eric;Weller, Hilary
通讯作者：
Weller, Hilary