Observed and simulated multidecadal variability in the Northern Hemisphere
Observed and simulated multidecadal variability in the Northern Hemisphere
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DOI：
10.1007/s003820000075
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发表时间：
2000-09-01
期刊：
影响因子：
4.6
通讯作者：
Mann, ME
中科院分区：
文献类型：
--
作者：
Delworth, TL;Mann, ME
对过去330年基于代理的地表温度重建的分析表明，存在着一种独特的振荡变化模式，其时间尺度大约为70年。这种可变性也见于仪器记录，尽管由于仪器记录的长度较短，这种可变性的振荡性质很难评估。这种变化的空间模式是半球的，甚至可能是全球的，但特别强调大西洋地区。对两个版本的GFDL大气-海洋耦合模式的多世纪积分的独立分析也表明，北大西洋地区存在明显的数十年变化，这与观测到的模式相似。模式的可变性涉及北大西洋温盐环流强度的波动。在这里，我们的目的是利用现有的仪器分析和新获得的基于代理的多世纪表面温度估计，将观测到的可变性与在海洋-大气耦合模式中模拟的可变性进行直接比较。分析表明，模拟的北大西洋海面温度(SST)的年代际变化模式与观测到的模式基本一致。海平面压力的模型和观测值之间的一致性要小得多。对变率的季节分析表明，无论是模式还是观测值，海温似乎都是数十年信号的主要载体。
Analyses of proxy based reconstructions of surface temperatures during the past 330 years show the existence of a distinct oscillatory mode of variability with an approximate time scale of 70 years. This variability is also seen in instrumental records, although the oscillatory nature of the variability is difficult to assess due to the short length of the instrumental record. The spatial pattern of this variability is hemispheric or perhaps even global in scale, but with particular emphasis on the Atlantic region. Independent analyses of multi century integrations of two versions of the GFDL coupled atmosphere-ocean model also show the existence of distinct multidecadal variability in the North Atlantic region which resembles the observed pattern. The model variability involves fluctuations in the intensity of the thermohaline circulation in the North Atlantic. It is our intent here to provide a direct comparison of the observed variability to that simulated in a coupled ocean-atmosphere model, making use of both existing instrumental analyses and newly available proxy based multi-century surface temperature estimates. The analyses demonstrate a substantial agreement between the simulated and observed patterns of multidecadal variability in sea surface temperature (SST) over the North Atlantic. There is much less agreement between the model and observations for sea level pressure. Seasonal analyses of the variability demonstrate that for both the model and observations SST appears to be the primary carrier of the multidecadal signal.