Analysis of observed and simulated SST spectra in the midlatitudes
Analysis of observed and simulated SST spectra in the midlatitudes
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DOI：
10.1007/s00382-002-0229-9
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发表时间：
2002-07
期刊：
影响因子：
4.6
通讯作者：
D. Dommenget;M. Latif
中科院分区：
文献类型：
--
作者：
D. Dommenget;M. Latif
对来自观测和全球海洋-大气耦合模式层次的月平均海表温度（SST）进行了统计分析，重点是中纬度地区（25°N-50°N）。模拟SST的谱已经针对Hasselmann随机气候模型的零假设进行了测试，该模型假设SST变率在其最简单的版本中为AR（1）过程。结果表明，在观测资料中以及在具有完全动力海洋模式的大气环流模式中，SST变率的谱与AR（1）过程有很大的不同，而在与板状海洋耦合的大气环流模式中，SST变率的谱与AR（1）过程是一致的。SST谱与AR（1）谱的偏差不是由于谱峰，而是由于从季节到年代际时间尺度的方差增加较慢。这些差异部分可归因于混合层和亚混合层海洋之间的相互作用。虽然混合层深度变化在季节和较短时间尺度上产生SST变化，但与深海的热交换减少了较长时间尺度上的变化。
Statistical analyses of monthly mean sea surface temperatures (SST) from observations and from a hierarchy of global coupled ocean–atmosphere models were carried out with the focus on the midlatitudes (25°N–50°N). The spectra of the simulated SSTs have been tested against the null hypothesis of Hasselmann's stochastic climate model, which assumes an AR(1)-process for the SST variability in its simplest version. It was found that the spectra of the SST variability in the observations and in the CGCMs with fully dynamical ocean models differ significantly from AR(1)-processes, while the SST variability in an AGCM coupled to a slab ocean is consistent with an AR(1)-process. The deviations of the SST spectra from the fitted AR(1) spectra are not due to spectral peaks but are due to a slower increase of variance from seasonal to decadal time scales. Parts of these differences can be attributed to the interaction between the mixed layer and the sub-mixed-layer ocean. While the mixed layer depth variability generates SST variability on seasonal and shorter time scales, the heat exchange with the deep ocean, reduces variability on longer time scales.