Earth's orbital asymmetries share recurring rhythms with El Niño, study finds

The study published in Frontiers in Earth Science reveals a potential link between Earth's orbital asymmetries and the recurring patterns of El Niño. For years, oceanographers and meteorologists have studied the complex mechanisms behind the El Niño-Southern Oscillation (ENSO), but the specific timing of ENSO has remained a mystery.

The research, conducted by Professor Guillermo A. Chinni, explores whether astronomical rhythms in Earth's orbit could provide a background tempo for this climate cycle. The investigation focused on subtle, continuous geometric shifts in Earth's orbit from year to year, examining the evolving asymmetry between the March and September equinoxes.

By analyzing 78 years of historical ENSO records, the study found recurring timescales of around 2.5-3 years, 4 years, and 11-13 years. While the findings do not claim that orbital geometry directly triggers individual El Niño events, they propose a conceptual framework centered on energetic preconditioning. In this framework, slowly evolving orbital boundary conditions shape the energetic background on which ocean-atmosphere mechanisms, such as equatorial Kelvin and Rossby waves, operate and amplify.

This hypothesis can be tested in real time, as the orbital descriptors used in the study are derived from deterministic astronomical ephemerides. The findings encourage closer collaboration between astronomers, oceanographers, and climate scientists to better understand the relationship between Earth's geometry and climate variability.