Stuecker Malte F
Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA.
Cooperative Programs for the Advancement of Earth System Science (CPAESS), University Corporation for Atmospheric Research (UCAR), Boulder, Colorado, USA.
Sci Rep. 2018 Feb 16;8(1):3216. doi: 10.1038/s41598-018-21537-0.
Numerous studies demonstrated that the Pacific Meridional Mode (PMM) can excite Central Pacific (CP) El Niño-Southern Oscillation (ENSO) events and that the PMM is mostly a stochastic phenomenon associated with mid-latitude atmospheric variability and wind-evaporation-SST feedback. Here we show that CP sea surface temperature (SST) variability exhibits high instantaneous correlations both on interannual (ENSO-related) and decadal (Pacific Decadal Oscillation (PDO)-related) timescales with the PMM. By prescribing an idealized interannual equatorial CP ENSO SST forcing in a partially-coupled atmosphere/slab ocean model we are able to generate a realistic instantaneous PMM response consistent with the observed statistical ENSO/PMM relationship. This means that CP ENSO and the PMM can excite each other respectively on interannual timescales, strongly suggesting that a fast positive feedback exists between the two phenomena. Thus, we argue that they cannot be considered two independent dynamical entities. Additionally, we show that the interannual CP ENSO SST forcing generates atmospheric circulation variability that projects strongly on the Aleutian Low and North Pacific SST anomalies that exhibit the characteristic PDO pattern.
大量研究表明，太平洋经向模态（PMM）能够激发中太平洋（CP）厄尔尼诺 - 南方涛动（ENSO）事件，且PMM主要是一种与中纬度大气变率及风 - 蒸发 - 海表温度反馈相关的随机现象。在此我们表明，CP海表温度（SST）变率在年际（与ENSO相关）和年代际（与太平洋年代际振荡（PDO）相关）时间尺度上均与PMM呈现出高瞬时相关性。通过在一个部分耦合的大气/平板海洋模型中规定理想化的年际赤道CP ENSO SST强迫，我们能够产生与观测到的统计ENSO/PMM关系一致的现实瞬时PMM响应。这意味着CP ENSO和PMM在年际时间尺度上能够相互激发，强烈表明这两种现象之间存在快速正反馈。因此，我们认为它们不能被视为两个独立的动力学实体。此外，我们表明年际CP ENSO SST强迫产生的大气环流变率在阿留申低压和呈现典型PDO模式的北太平洋SST异常上有强烈投影。
