The relative impacts of El Niño Modoki, canonical El Niño, and QBO on tropical ozone changes since the 1980s

Abstract

Some studies showed that since the 1980s Modoki activity-a different sea surface temperature anomaly pattern from canonical El Nino-Southern Oscillation (ENSO) in the tropics-has been increasing in frequency. In the light of an analysis of the observations and simulations, we found that Modoki, as a new driver of global climate change, can modulate the tropical upwelling that significantly affects mid-lower stratospheric ozone. As a result, it has an important impact on the variations of tropical total column ozone (TCO), alongside quasi-biennial oscillation or canonical ENSO. Our results suggest that, in the context of future global warming, Modoki activity may continue to be a primary driver of tropical TCO changes. Besides, it is possible can serve as a predictor of tropical TCO variations since Modoki events precede tropical ozone changes.