Separating the North and South Pacific Meridional Modes Contributions to ENSO and Tropical Decadal Variability
Separating the North and South Pacific Meridional Modes Contributions to ENSO and Tropical Decadal Variability
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DOI：
10.1029/2018gl080320
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发表时间：
2019-01
影响因子：
5.2
通讯作者：
G. Liguori;E. Di Lorenzo
中科院分区：
文献类型：
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作者：
G. Liguori;E. Di Lorenzo
南北太平洋经向模态（NPMM 和 SPMM）是厄尔尼诺南方涛动 (ENSO) 和热带太平洋年代际变率 (TPDV) 的已知前兆。然而，这些前兆的相对重要性以及它们影响热带的时间尺度仍不清楚。使用社区地球系统模型的 30 个成员集合作为控制气候，我们生成了两个额外的成员，其中 NPMM 和 SPMM 被选择性抑制。我们发现两种经向模态在不同的时间尺度上独立地激发热带方差。缺乏 NPMM 会导致热带年际变率显着降低（约 35%），而缺乏 SPMM 对 ENSO 没有明显影响，但会显着降低 TPDV（约 30%）。虽然 NPMM 和 SPMM 的相对重要性可能取决于模型，但为经向模式提供能量的温带随机大气变率成为 TPDV 的关键来源。
North and South Pacific Meridional Modes (NPMM and SPMM) are known precursors of El Niño–Southern Oscillation (ENSO) and Tropical Pacific decadal variability (TPDV). However, the relative importance of these precursors and the timescale on which they impact the tropics remain unclear. Using a 30‐member ensemble of the Community Earth System Model as the control climate, we generate two additional members where the NPMM and SPMM are selectively suppressed. We find that both meridional modes energize the tropical variance independently on different timescales. The absence of NPMM leads to a significant reduction of the tropical interannual variability (~35%), while the absence of the SPMM has no appreciable impact on ENSO but significantly reduces the TPDV (~30%). While the relative importance of the NPMM and SPMM may be model dependent, the stochastic atmospheric variability in the extratropics that energizes the meridional modes emerges as a key source of TPDV.