Madden Julian oscillation modulation for surface ozone in Peninsular Malaysia

摘要

This study investigates the modulation of Madden-Julian Oscillation (MJO) on surface ozone (O-3) variability in Peninsular Malaysia. A 17-years (2000-2016) record of daily maximum surface ozone (O-3Max) concentration from 24 air quality monitoring stations across Peninsular Malaysia were divided into six sub-regions namely R1, R2, R3, R4, R5 and R6. To investigate MJO modulation on O-3Max, total cloud cover (TCC), surface air temperature (SAT) and surface wind from ERA Interim Reanalysis were also analyzed. MJO composites of O-3Max and meteorological parameters were created based on the Real-Time Multivariate (RMM) Index. Result shows that O-3Max concentration varies remarkably with MJO phases. Low O-3Max days occurred mostly during phase 2 (R2, R3, R4, R5 and R6) and phase 3 (R1) of MJO with concentration ranging from 31 to 47 ppb. While high O-3Max days commonly occurred during phase 5 (R6), 6 (R1, R2, R3 and R5) and 8 (R4) of MJO with averaged concentration ranging from 41 to 57 ppb. All meteorological parameters vary with MJO phases and were consistent with O-3Max variability patterns in Peninsular Malaysia, with positive (negative) TCC anomalies and negative (positive) SAT anomalies occur during the days when O-3 concentration is low (high).