Impact of the Madden-Julian oscillation on boreal autumn surface ozone in Guangdong Province, China

Sijia Hu ¹, Run Liu ², Caixian Huang ¹

⁰Institute for Environmental and Climate Research, College of Environmental and Climate, Jinan University, Guangzhou, China.

Environmental Research +

|

February 1, 2025

View abstract on PubMed

Summary

Stronger Madden-Julian Oscillation (MJO) events correlate with higher surface ozone levels in Guangdong, China. Weaker MJO events are linked to lower ozone concentrations, impacting air quality during autumn months.

Area Of Science

Atmospheric Science
Climate Science
Environmental Science

Background

The Madden-Julian Oscillation (MJO) is a dominant mode of sub-seasonal tropical atmospheric variability.
Surface ozone (O3) is a key air pollutant with significant impacts on human health and ecosystems.
Understanding the influence of large-scale climate patterns on regional air quality is crucial for environmental management.

Purpose Of The Study

To investigate the relationship between the MJO and surface ozone concentrations in Guangdong Province, southern China.
To determine how MJO intensity and phase influence O3 levels and exceedance probabilities.
To explore the meteorological conditions associated with these relationships.

Main Methods

Utilized the Real-time Multivariate Madden-Julian Oscillation (RMM) index and NCEP/NCAR reanalysis data.
Classified MJO events into strong (S-MJO) and weak (W-MJO) based on RMM amplitude.
Analyzed surface O3 concentrations and exceedance probabilities (O3 > 160 μg m⁻³) during boreal autumn (September-November) from 2015-2023.

Main Results

A significant positive correlation was found between MJO intensity and surface O3 concentration in Guangdong.
Higher probabilities of O3 exceedance were observed during S-MJO events compared to W-MJO events.
Specific MJO phases (1, 6, 8) were associated with higher O3, while phases 3 and 4 showed lower O3 concentrations.
Meteorological conditions during S-MJO favored O3 formation and accumulation, while W-MJO conditions promoted dispersion.

Conclusions

MJO intensity and convective center position significantly influence regional surface ozone levels in Guangdong.
The study provides a novel framework for understanding the interplay between large-scale climate modes and regional air quality.
Findings highlight the importance of considering MJO variability in air quality forecasting and management strategies.

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