Robust Decadal Variations in ENSO Diversity, and its Impact on Future Scenarios

Bastien Dieppois (1, 2) , Antonietta Capotondi (3, 4) , Benjamin Pohl (5) , Kwok Pan Chun (6) , Paul-Arthur Monerie (7) , Jonathan Eden (1)

1 CAWR - Centre for Agroecology, Water and Resilience
2 Department of Oceanography [Cape Town]
3 CIRES - Cooperative Institute for Research in Environmental Sciences
4 PSL - NOAA Physical Sciences Laboratory
5 BGS - Biogéosciences [UMR 6282]
6 Department of Geography
7 Department of Meteorology [Reading]

El Niño-Southern Oscillation (ENSO) shows a large diversity of events that is modulated by climate variability and change. The representation of this diversity in climate models limits our ability to predict their impact on ecosystems and human livelihood. Here, we use multiple observational datasets to provide a probabilistic description of historical variations in event location and intensity, and to benchmark models, before examining future system trajectories. We find robust decadal variations in event intensities and locations in century-long observational datasets, which are associated with perturbations in equatorial wind-stress and thermocline depth, as well as extra-tropical anomalies in the North and South Pacific. Some climate models are capable of simulating such decadal variability in ENSO diversity, and the associated large-scale patterns. Projections of ENSO diversity in future climate change scenarios strongly depend on the magnitude of decadal variations, and the ability of climate models to reproduce them realistically over the 21 st century.

Domaines: Climatologie

Bastien Dieppois, Antonietta Capotondi, Benjamin Pohl, Kwok Pan Chun, Paul-Arthur Monerie, et al.. Robust Decadal Variations in ENSO Diversity, and its Impact on Future Scenarios. Communications Earth & Environment, 2021, 2 (1), pp.212. ⟨10.1038/s43247-021-00285-6⟩. ⟨hal-03380560⟩