El Niño‐Southern Oscillation and Indian Ocean Dipole contribution to the zonal mean total ozone in the Northern Hemisphere

Abstract

ABSTRACTWe present the first analysis of the combined El Niño‐Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) contribution to the monthly zonal means of total ozone (TO3) in the Northern Hemisphere for the 1970–2015 period. The Solar Backscatter UV merged TO3 (version 8.6) data set is examined using the standard multiple regression model with new proposed regressors accounting for the impact of the strong ENSO and IOD effects on the zonal mean ozone. The new regressors are selected using the principal component analysis applied to the standard ENSO and IOD indices. The ENSO and IOD induce ±2% month‐to‐month TO3 oscillations in the equatorial‐, mid‐, and even in high latitudinal zones. Long‐term effects of ∼1% 10 year−1 are found. In autumn, a strong positive phase IOD is associated with ∼0.5% positive and ∼1.5% negative anomalies in the 30°–35°N and 65°–70°N regions, respectively. The IOD contribution to the zonal TO3 means is more pronounced than that of ENSO.