A theory of Spring Persistence Barrier on ENSO. Part II: Persistence Barriers in SST and ocean heat content

Abstract

In this paper, we investigate the potential factors that control the relationship between the El Niño-Southern Oscillation (ENSO) persistence barriers (PB) in sea surface temperature (SST) and ocean heat content (OHC) and apply it to explain observational ENSO PBs. With the addition of seasonal growth rate in SST in the neutral recharge oscillator (NRO) model, approximate analytical solutions of autocorrelation functions for SST and OHC suggest strictly that the timing of PB for OHC leads that of SST by half a year and the strength of the two PBs are the same. The numerical solutions of the NRO model also show a similar relationship. The role of ENSO growth rate to PBs in SST and OHC is then identified in the damped and unstable ENSO regime. Therefore, it is suggested that for the observational ENSO, the seasonally varying ENSO growth rate in SST controls PBs in SST and OHC simultaneously.

The Role of Extratropical Pacific in Crossing ENSO Spring Predictability Barrier

“…One possible reason that leads to this SPB is the specific initial errors in the tropical Pacific (Mu, Duan, & Wang, 2007, 2007b). However, recent studies have identified numerically and analytically that the seasonally varying background of the tropical Pacific may be an important factor in causing the SPB (Y. Jin et al., 2019, 2020, 2021; Y. Jin and Liu, 2021a, b; A. F. Levine and McPhaden, 2015; Liu et al., 2019).…”