Special Seminar: Subsurface Ocean Turbulent Mixing Enhances Central Pacific ENSO via Positive Feedback
Since the 21st century, the El Niño and Southern Oscillation (ENSO) exhibits more pronounced signals in the central Pacific (CP) rather than the eastern Pacific (EP), but the prediction skill has waned, suggesting limited under- standing of crucial dynamics within the prediction framework. The ocean mixing around the mixed layer base, which transfers heat downward in a diabatic manner, was considered a potential influencing factor; yet, its effect has not been adequately examined in either CP or EP regions due to insuffi- cient data. Here, we propose an Argo profile data-based mixing estimation model, which yields abundant estimates of subsurface ocean mixing and tur- bulent heat flux. Consequently, we find significant positive feedback of the ocean mixing-induced diabatic warming/cooling on the CP ENSO, but not on the EP ENSO. Particularly, the diabatic effect dominates sea surface tempera- ture change in the CP region, highlighting the necessity for diabatic CP ENSO positive feedback dynamics in prediction models.
Date
19.09.2025
Time
11:00 h
Place
- Bundesstr. 53, room 133
- Bundesstr. 53,, 20146 Hamburg