@article{fdi:010092880,
  title = {{T}he evolutions of single-year and multiyear {E}l {N}iño from preconditioning to decay stages : direct wind-driven versus boundary-reflected oceanic responses},
  author = {{L}ee, {C}. {W}. {E}. and {S}ui, {C}. {H}. {S}. and {I}zumo, {T}akeshi},
  editor = {},
  language = {{ENG}},
  abstract = {{A}dvancing our understanding of single-year and multiyear {E}l {N}iño events is essential for a better forecast of {E}l {N}iños and assessment of their global socioeconomic impacts. {H}ere, we compare these two types of {E}l {N}iños in reanalysis and coupled model data. {W}e further develop an approach in a linear continuously stratified ocean model to quantifying direct wind-driven ({DWD}) and boundary-reflected ({BR}) responses to wind stress forcing from the reanalysis and coupled model datasets. {F}or single-year {E}l {N}iños, the positive {N}orth {P}acific meridional mode charges additional heat content to the tropical {P}acific through {DWD} processes in year21 before the development year (year0), leading to the earlier event development. {T}he subsequent discharge and zonal-advective reflective feedbacks by {BR} processes also start earlier and are intensified by wind anomalies of a more eastward fetch. {F}inally, during the mature boreal winter and decay spring in year1, the equatorial western {P}acific winds turn into easterlies, terminating {DWD} downwelling {K}elvin waves and the positive feedback. {I}n contrast, multiyear {E}l {N}iños feature a lower preconditioning recharge state in year21, later development and less eastward-extending wind and sea surface temperature anomalies in year0, and weaker delayed negative feedbacks and persistent western {P}acific westerly winds in year1. {T}he resultant insufficient {BR} negative feedbacks and lasting {DWD} downwelling {K}elvin waves allow {E}l {N}iño to continue into year1/year2. {T}he approach developed here and the results that show the fundamental dynamic processes regulating {E}l {N}iño's duration should help in improving {E}l {N}iño-{S}outhern {O}scillation ({ENSO}) seasonal forecasting. {SIGNIFICANCE} {STATEMENT}: {E}l {N}iño events have global climate impacts, but their duration from single- to multiyear is a challenging prediction problem. {H}ere, we investigate the mechanisms determining their duration. {W}e analyze their evolutions and quantify wind-forced ocean responses. {W}e show that the early establishment of tropical {P}acific warm water volume, the eastward shift of wind stresses, and the center of warm sea surface temperature influence the strength and timing of the following negative feedbacks that modulate an event's decay. {T}he {E}l {N}iño's spatial and temporal diversities are linked by dynamical processes. {T}he above mechanisms can be applied to observation monitoring, model, and forecast diagnosis. {I}t could potentially help in mitigating the global socioeconomic and environmental impacts of {ENSO}.},
  keywords = {{E}l {N}ino ; {ENSO} ; {A}tmosphere-ocean interaction ; {C}limate variability ; {PACIFIQUE}, {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{J}ournal of {C}limate},
  volume = {38},
  numero = {5},
  pages = {1205--1220},
  ISSN = {0894-8755},
  year = {2025},
  DOI = {10.1175/jcli-d-24-0172.1},
  URL = {https://www.documentation.ird.fr/hor/fdi:010092880},
}