Predicting Pacific Decadal Variability
Predicting Pacific Decadal Variability
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预测太平洋年代际变化
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Jennifer Velez
中科院分区：
文献类型：
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作者：
R. Seager;A. Karspeck;M. Cane;Y. Kushnir;A. Giannini;A. Kaplan;B. Kerman;Jennifer Velez
提出了太平洋地区气候年代际变率是由热带海气相互作用驱动并传递给热带外大气的观点。结果表明，在过去的世纪热带年代际变化可能会出现的结果，包含在厄尔尼诺-南方涛动的中间模型的物理区域子集。这些ENSO和热带平均气候的年代际变化比提前几年的机会更容易预测，但即使在这些理想化的实验中，预测技巧也可能太小而无用。尽管如此，对未来20年的预测表明，根据这一模式，1998年的厄尔尼诺标志着1976年后热带太平洋温暖期的结束。观测和大气环流模式的解释表明，1960年代和1980年代之间的北太平洋上空的大气环流的年代际变化的热带强迫和内部大气变率的混合解释。这限制了它们的可预测性。海洋对热带外大气变率的响应包括瞬时的局部响应和可提前几年预测的副热带和副极地环流的延迟响应。结果表明，冬季阿留申低压的内部变率对ENSO系统的影响很弱，但对年代际可预报性的影响很小。
The case is advanced that decadal variability of climate in the Pacific sector is driven by tropical atmosphere-ocean interactions and communicated to the extratropics. It is shown that tropical decadal variations in the last century could arise as a consequence of the regional subset of physics contained within an intermediate model of the El Nino-Southern Oscillation. These decadal changes in ENSO and tropical mean climate are more predictable than chance years in advance but even in these idealized experiments forecast skill is probably too small to be useful. Nonetheless, forecasts of the next two decades indicate that, according to this model, the 1998 El Nino marked the end of the post 1976 tropical Pacific warm period. Observations and atmosphere general circulation models are interpreted to suggest that decadal variations of the atmosphere circulation over the North Pacific between the 1960s and the 1980s are explained by a mix of tropical forcing and internal atmospheric variability. This places a limit on their predictability. The ocean response to extratropical atmosphere variability consists of a local response that is instantaneous and a delayed response of the subtropical and subpolar gyres that is predictable a few years in advance. It is shown that the wintertime internal variability of the Aleutian Low can weakly impact the ENSO system but its impact on decadal predictability is barely discernible.