Work

On the Mechanisms of the Atlantic Niño/Niña Decadal Variability

Year: 2025

Type: article

Abstract: The observed Atlantic Niño/Niña displays robust variations at decadal timescale (decadal ATL), besides the well‐known interannual variability. The underlying mechanisms, however, remain largely elusive. Analyzing observations and model outputs, we find the decadal ATL originates in the South Atlantic. During its positive phase, the cold tongue warming, triggering atmospheric Rossby wave train, weakens the St. Helena anticyclone, which enhances wind and cools sea surface temperature over the Southwestern Atlantic, leading to the positive phase of the South Atlantic Ocean Dipole. Meanwhile, the weakened anticyclone reduces the transport of the subtropical cell, suppressing the equatorial upwelling, which amplifies the initial cold tongue warming. The phase shift of the decadal ATL is attributed to an eastward propagation of thermocline displacements at 3°S–15°S, induced by a propagation of local wind stress curl anomalies in response to combined effects of the equatorial and mid‐latitude air‐sea coupling.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl117231

Authors: Yun Yang, Lixin Wu, Chunxue Yang, Yuhu Chen, Hong Wang

Institutions: Beijing Normal University, Laoshan Laboratory, Ocean University of China, National Research Council

Language: English

Topic: Climate variability and models

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDGs: Climate action, Life below water

Open Access status: gold

Estimated APC paid: $3,190