On The Estimation of Internal Climate Variability During the Preindustrial Past Millennium
On The Estimation of Internal Climate Variability During the Preindustrial Past Millennium
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DOI：
10.1029/2021gl096596
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发表时间：
2022-01
影响因子：
5.2
通讯作者：
M. Mann;B. Steinman;D. Brouillette;A. Fernandez;S. Miller
中科院分区：
文献类型：
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作者：
M. Mann;B. Steinman;D. Brouillette;A. Fernandez;S. Miller
我们使用一个耦合模型（NCAR社区地球系统模型）的模拟集合，该模型由过去一千年工业化前的自然辐射强迫估计驱动，以测试旨在从基于代理的气候重建中消除强迫变率的方法的有效性，并估计剩余内部变率（例如，一个假定的“大西洋多年代际振荡”）。在这些实验的框架内，表面温度变化的强迫分量可以从集合平均值准确地估计，并且每个独立实现的内部可变性可以通过减去该估计来准确地评估。在这种情况下，我们表明，在真实的内部变率已知的情况下，基于回归的方法从代理重建中去除强迫分量，在基础自然辐射强迫存在不确定性的情况下，无法产生准确的估计，错误地将未解决的强迫特征（以及与之相关的数十年谱峰）归因于内部变率。
We use an ensemble of simulations of a coupled model (NCAR Community Earth System Model) driven by natural radiative forcing estimates over the pre‐industrial past millennium to test the efficacy of methods designed to remove forced variability from proxy‐based climate reconstructions and estimate residual internal variability (e.g., a putative “Atlantic Multidecadal Oscillation”). Within the framework of these experiments, the forced component of surface temperature change can be estimated accurately from the ensemble mean, and the internal variability of each of the independent realizations can be accurately assessed by subtracting off that estimate. We show in this case, where the true internal variability is known, that regression‐based methods of removing the forced component from proxy reconstructions will, in the presence of uncertainties in the underlying natural radiative forcing, fail to yield accurate estimates thereof, incorrectly attributing unresolved forced features (and multidecadal spectral peaks associated with them) to internal variability.