The mid-1970s climate shift in the Pacific and the relative roles of forced versus inherent decadal variability.
The mid-1970s climate shift in the Pacific and the relative roles of forced versus inherent decadal variability.
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DOI：
10.1175/2008jcli2552.1
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发表时间：
2009-02
影响因子：
4.9
通讯作者：
G. Meehl;A. Hu;B. Santer
中科院分区：
文献类型：
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作者：
G. Meehl;A. Hu;B. Santer
热带太平洋海面温度 (SST) 发生了从较冷到较暖的显着转变，这是与年代间太平洋涛动 (IPO) 向正阶段过渡有关的流域范围海温异常模式的一部分，这种转变发生在 20 世纪 70 年代中期，其影响波及全球。一种观点认为，这种变化完全是自然的，是太平洋气候系统内部产生的十年变率的产物。然而，在 20 世纪 70 年代中期，全球气温也显着升高，并且与外部强迫变化相关的许多其他量也发生了变化，特别是燃烧化石燃料导致的温室气体增加。对观测结果的分析、全球耦合气候模型的非受迫控制以及 20 世纪外部强迫变化的模拟表明，观测到的 20 世纪 70 年代的气候变化有外部强迫变化的影响，而外部强迫的变化可能与太平洋气候系统固有的年代际波动相叠加。因此，与 IPO 相关的这种固有的年代际变化将 IPO 的消极阶段推迟到 1970 年代，而 1960 年代可能会迫使气候从 IPO 的消极阶段转向积极阶段。
A significant shift from cooler to warmer tropical Pacific sea surface temperatures (SSTs), part of a pattern of basinwide SST anomalies involved with a transition to the positive phase of the Interdecadal Pacific Oscillation (IPO), occurred in the mid-1970s with effects that extended globally. One view is that this change was entirely natural and was a product of internally generated decadal variability of the Pacific climate system. However, during the mid-1970s there was also a significant increase of global temperature and changes to a number of other quantities that have been associated with changes in external forcings, particularly increases of greenhouse gases from the burning of fossil fuels. Analysis of observations, an unforced control run from a global coupled climate model, and twentieth-century simulations with changes in external forcings show that the observed 1970s climate shift had a contribution from changes in external forcing superimposed on what was likely an inherent decadal fluctuation of the Pacific climate system. Thus, this inherent decadal variability associated with the IPO delayed until the 1970s what likely would have been a forced climate shift in the 1960s from a negative to positive phase of the IPO.