Exploring the impact of CMIP5 model biases on the simulation of North Atlantic decadal variability
Exploring the impact of CMIP5 model biases on the simulation of North Atlantic decadal variability
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DOI：
10.1002/2015gl064360
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发表时间：
2015-07-28
影响因子：
5.2
通讯作者：
Hunt, Jonathan A.
中科院分区：
文献类型：
--
作者：
Menary, Matthew B.;Hodson, Daniel L. R.;Hunt, Jonathan A.
仪器观测，古代理，气候模式表明显着的年代际变化在北大西洋副极地环流（NASPG）。然而，一个采样差的观测记录和模式行为的多样性意味着这种变异的确切性质和机制尚不清楚。在这里，我们分析了一个非常大的多模式合奏的42个当代气候模式，以测试是否NASPG平均状态偏差系统地影响代表性的年代际变化。拉布拉多海的温度和盐度偏差协变和影响密度变化是否由温度或盐度变化控制。海洋水平分辨率是一个很好的预测的偏差和主导的动力反馈在NASPG的位置。然而，我们没有发现任何链接的光谱特性的变化。我们的研究结果表明，平均状态和机制的变异内NASPG是不独立的。这是使用异常同化方法进行年代际预测的一个重要警告。
Instrumental observations, paleoproxies, and climate models suggest significant decadal variability within the North Atlantic subpolar gyre (NASPG). However, a poorly sampled observational record and a diversity of model behaviors mean that the precise nature and mechanisms of this variability are unclear. Here we analyze an exceptionally large multimodel ensemble of 42 present-generation climate models to test whether NASPG mean state biases systematically affect the representation of decadal variability. Temperature and salinity biases in the Labrador Sea covary and influence whether density variability is controlled by temperature or salinity variations. Ocean horizontal resolution is a good predictor of the biases and the location of the dominant dynamical feedbacks within the NASPG. However, we find no link to the spectral characteristics of the variability. Our results suggest that the mean state and mechanisms of variability within the NASPG are not independent. This represents an important caveat for decadal predictions using anomaly assimilation methods.