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

This study uses the Real-time Multivariate Madden-Julian Oscillation (MJO) index (RMM), along with meteorological data from NCEP/NCAR reanalysis datasets, to conduct a synthetic analysis of the MJO and surface ozone (O) concentration in Guangdong Province, southern China during the boreal autumn months (September-October-November, SON) from 2015 to 2023. The MJO is classified into strong MJO (S-MJO) and weak MJO (W-MJO) using a RMM amplitude threshold of 1. The findings reveal a significant positive correlation between the intensity of the MJO, as indicated by the RMM index, and the SON surface O concentration in Guangdong Province over these nine years; specifically, the greater the MJO intensity, the higher the SON surface O concentration, whereas the smaller the MJO intensity, the lower the concentration.