Differences and Causes of Interannual Variations of Global Mean Sea Level Between Two El Niño Events in 2014–2016 and 2023–2024

Abstract The interannual variation of global mean sea level is closely related to El Niño‐Southern Oscillation. During the 2014–2016 and 2023–2024 El Niño event development phases (October 2014–December 2015 and May 2023–December 2023, respectively), the interannual component of global mean sea level rose by approximately 9.16 and 7.70 mm, respectively. By combining satellite gravimetry and Argo gridded products, we show that barystatic sea level rise played a dominant role in the global mean sea level budget during both events. Although the barystatic sea level rise reached comparable magnitudes of 6.20 and 6.26 mm in the 2014–2016 and 2023–2024 development phases, respectively, the 2023–2024 surge was significantly more rapid, occurring over a much shorter duration. This accelerated rise was primarily driven by terrestrial water storage depletion in the America and Africa. Notably, South America exhibited a significantly faster rate of storage loss during the development phase of the 2023–2024 event compared to that of the 2014–2016 event. The steric sea level rise during the 2014–2016 and 2023–2024 development phases was 3.11 and 1.60 mm, respectively. Further analysis indicates that the steric sea level rise during the 2023–2024 development phase was predominantly driven by the thermosteric component, with a substantial contribution originating from the Indian Ocean. This regional anomaly was likely driven by the simultaneous occurrence of a peak positive Indian Ocean Dipole and El Niño.