@article{PAR00030643,
  title = {{R}ealistic {ENSO} dynamics requires a damped nonlinear recharge oscillator},
  author = {{H}an, {S}. and {P}edorov, {L}. and {V}ialard, {J}{\'e}r{\^o}me},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he dynamics of {E}l {N}i & ntilde;o-{S}outhern {O}scillation ({ENSO}) are succinctly captured by the recharge oscillator ({RO}) framework. {H}owever, to simulate {ENSO} realistically, careful choices must be made regarding the {RO}'s key parameters. {I}n particular, nonlinear parameters govern how well the model reproduces {ENSO} asymmetries {E}l {N}i & ntilde;o events tend to be stronger but relatively short, often transitioning into {L}a {N}i & ntilde;a, whereas {L}a {N}i & ntilde;a events are typically weaker but may last longer. {W}hile amplitude asymmetry has been studied within the {RO} framework, duration and transition asymmetries remain less explored and their causes are debated. {I}n this study, by systematically exploring the {RO} parameter spacerather than relying on commonly used fitting methods we identify optimal parameter values that successfully capture key linear and nonlinear {ENSO} characteristics. {I}n doing so, we revisit several foundational elements of the {RO} framework. {F}irst, we analytically derive the phase relationship between temperature and heat content anomalies, showing that it depends on the signs of the {B}jerknes feedback and the ocean damping time scale. {W}e show that self-sustained oscillations fail to reproduce the observed kurtosis of {N}i & ntilde;o indices. {W}e further derive an analytical expression for the power spectrum and argue that incorporating red noise forcing, rather than white noise, introduces unnecessary complexity. {T}he most realistic yet simplest {RO} configuration is a strongly damped oscillator, with a decay time scale shorter than the dominant period, forced by multiplicative white noise and influenced by weak deterministic nonlinearities. {I}dentifying these minimal components preserves the {RO} framework's clarity and isolates the core physical processes underlying {ENSO} behavior.},
  keywords = {{ENSO} ; {N}umerical analysis/modeling ; {I}dealized models ; {S}tochastic models},
  booktitle = {},
  journal = {{J}ournal of {C}limate},
  volume = {39},
  numero = {1},
  pages = {77--101},
  ISSN = {0894-8755},
  year = {2026},
  DOI = {10.1175/jcli-d-25-0250.1},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00030643},
}