Controls of Spring Persistence Barrier Strength in Different ENSO Regimes and Implications for 21st Century Changes

Summary, in English

This paper investigates potential factors that control the El Niño–Southern Oscillation (ENSO) Spring Persistence Barrier (SPB) strength in two different ENSO regimes and apply it to explain the ENSO SPB strength modulation after the 21st century. In a damped, noise-driven model, the theoretical solution of SPB strength illustrates that a weaker ENSO growth rate strengthens SPB. In the self-sustained regime, as in the Cane-Zebiak model (chaotic system), the strengthened thermodynamic damping and weakened thermocline positive feedback lead to a more negative ENSO growth rate and, in turn, a stronger SPB. Therefore, in both ENSO regimes, a weaker ENSO growth rate intensifies the SPB. The application of the theory to the real world suggests that a more negative ENSO growth rate, corresponding to a more damped feedback system, is responsible for the stronger SPB in recent decades than in 1980–2000.

• Author: Yishuai Jin; Zhengyao Lu; Zhengyu Liu
• Department/s: Dept of Physical Geography and Ecosystem Science; MERGE: ModElling the Regional and Global Earth system
• Publishing year: 2020
• Language: English
• Publication/Series: Geophysical Research Letters
• Volume: 47
• Issue: 11
• Links: http://dx.doi.org/10.1029/2020GL088010
• Document type: Journal article
• Publisher: American Geophysical Union (AGU)
• Topic: Geophysics
• Keywords: Bjerknes stability index; ENSO growth rate; seasonal persistence barrier strength; thermocline; thermodynamic damping
• Status: Published
• ISBN/ISSN/Other: ISSN: 0094-8276