Purpose of Review

This paper reviews recent progress in understanding of the North Pacific Meridional Mode (NPMM) and its influence on the timing, magnitude, flavor, and intensity of the El Niño-Southern Oscillation (ENSO).

Recent Findings

The NPMM is a seasonally evolving mode of coupled climate variability and features several distinct opportunities to influence ENSO. They include: (1) A Wind-Evaporation-SST (WES) feedback-driven propagation of surface anomalies onto the equator during boreal spring, (2) Trade Wind Charging (TWC) of equatorial subsurface heat content by NPMM-related surface wind stress curl anomalies in boreal winter and early spring, (3) The reflection of NPMM-forced ocean Rossby waves off the western boundary in boreal summer, and (4) A Gill-like atmospheric response associated with anomalous deep convection in boreal summer and fall. The South Pacific Meridional Mode (SPMM) also significantly modulates ENSO, and its interactions with the NPMM may contribute to ENSO diversity. Together, the NPMM and SPMM are also important components of Tropical Pacific Decadal Variability; however, future research is needed to improve understanding on these timescales.

Summary

Since 1950, the boreal spring NPMM skillfully predicts about 15–30% of observed winter ENSO variability. Improving simulated NPMM-ENSO relationships in forecast models may reduce ENSO forecasting error. Recent studies have begun to explore the influence of anthropogenic climate change on the NPMM-ENSO relationship; however, the results are inconclusive.

中文翻译：

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太平洋经向模态和 ENSO：回顾

审查目的

本文回顾了北太平洋经向模态（NPMM）及其对厄尔尼诺-南方涛动（ENSO）的时间、震级、风格和强度影响的最新进展。

最近的发现

NPMM 是一种耦合气候变率的季节性演变模式，具有影响 ENSO 的几个独特机会。它们包括：（1）北方春季期间风蒸发海温（WES）反馈驱动的地表异常传播到赤道，（2）NPMM相关地表风应力对赤道地下热含量的信风充电（TWC）北半球冬季和早春的旋度异常，（3）北半球夏季NPMM强迫海洋罗斯贝波在西边界的反射，以及（4）北半球夏季和秋季与异常深对流相关的吉尔状大气响应。南太平洋经向模态 (SPMM) 也显着调节 ENSO，其与 NPMM 的相互作用可能有助于 ENSO 多样性。 NPMM 和 SPMM 也是热带太平洋年代际变率的重要组成部分；然而，需要未来的研究来增进对这些时间尺度的理解。

概括

自 1950 年以来，北方春季 NPMM 巧妙地预测了观测到的冬季 ENSO 变化的约 15-30%。改善预报模型中模拟的 NPMM-ENSO 关系可能会减少 ENSO 预报误差。最近的研究开始探讨人为气候变化对NPMM-ENSO关系的影响；然而，结果尚无定论。