Understanding the Multi-year El Nino-Southern Oscillation (ENSO): Its Dynamics, El Nino-La Nina Asymmetries, and Climate Impacts

The El Niño-Southern Oscillation (ENSO) is one of the most powerful forces affecting Earth’s climate. ENSO events alter atmospheric and oceanic circulations, interrupting normal weather and climate patterns worldwide and impacting socioeconomic activities. Extensive research since the 1970s has produced frameworks capable of explaining the observed properties and impacts of ENSO as well as predictive models.

However, the properties and impacts of the ENSO events observed so far in the 21st century have been noticeably different from those observed in the 20th century. There are indications that the duration of ENSO events might have changed, shifting from single-year to multi-year events. Associated with these changes, ENSO’s impacts on global climate may have become different from those documented during the 20th century.

The investigator proposes in this research project that the underlying dynamics of the 21st-century ENSO may have become different from those in the 20th century, making its behavior more difficult to predict. The investigator proposes a new dynamical framework and a set of research methodologies to comprehensively examine and better understand the multi-year ENSO and its climate impacts.

This project offers a new ENSO dynamic to explain an emerging but not yet well understood aspect of ENSO properties – its multi-year evolutions. Prediction models and strategies can be revised and developed to better predict ENSO events and their climate impacts. Better ENSO predictions will help to improve disaster preparation.

The improved understanding of multi-year ENSOs can offer new and different ways to interpret paleoclimate data, which may lead to new insights into the history of Earth's climate and new implications for future climate changes. On the educational side, this project contributes to the training of graduate and undergraduate students enrolled in the rapidly expanding programs of the Earth System Science Department at UC Irvine.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.