Work

Limited nonlinearity of joint ENSO–QBO effects from the stratosphere to the troposphere

Year: 2025

Type: article

Abstract: Previous studies have explored the possible impact of joint El Niño–Southern Oscillation (ENSO)–Quasi-Biennial Oscillation (QBO) forcings on the northern winter stratospheric circulation. This study continues to investigate the relative contributions of the nonlinearity and linearity of joint ENSO–QBO forcings in the total circulation anomaly. The possible interference of ENSO (QBO) signals within QBO (ENSO) is removed before the pure QBO (ENSO) signals in the circulation are calculated. A linear superposition of the pure QBO+ENSO signals is compared with the joint ENSO–QBO composite patterns. It is revealed that the combined ENSO–QBO effect is nearly a linear summation of the pure ENSO+QBO signals in the stratosphere, displaying strong linearity. This linearity decreases slightly from the stratosphere to the troposphere, and the nonlinearity of the joint ENSO–QBO impact increases in regional tropospheric circulation. The linearity and nonlinearity of the joint ENSO–QBO impact in the troposphere are nonuniformly distributed: Lower-to-mid latitude circulation changes associated with configured ENSO–QBO forcings are nearly a linear combination of pure ENSO and QBO signals, while nonlinearity soon dominates the total circulation anomaly pattern at high latitudes, with the ENSO signals overwhelming the QBO signals, especially for the El Niño–EQBO (QBO easterly phase) configurations. This study provides evidence that linearity of the joint ENSO–QBO impact prevails in the stratosphere and tropical troposphere, while nonlinearity exists in the Arctic troposphere.

Source: Atmospheric and Oceanic Science Letters

DOI: 10.1016/j.aosl.2025.100704

Authors: Haoxiang Wang, Jian Rao, Dong Guo, Yimin Liu, Yixiong Lu

Institutions: Nanjing University of Information Science and Technology, Chinese Academy of Sciences, Institute of Atmospheric Physics, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, China Meteorological Administration

Language: English

Topic: Climate variability and models

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $1,200