@article{fdi:010075576,
  title = {{O}n the physical interpretation of the lead relation between {W}arm {W}ater {V}olume and the {E}l {N}ino {S}outhern {O}scillation},
  author = {{I}zumo, {T}akeshi and {L}engaigne, {M}atthieu and {V}ialard, {J}{\'e}r{\^o}me and {S}uresh, {I}. and {P}lanton, {Y}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {W}arm {W}ater {V}olume ({WWV}), a proxy for the equatorial {P}acific heat content, is the most widely used oceanic precursor of the {E}l {N}ino {S}outhern {O}scillation ({ENSO}). {T}he standard interpretation of this lead relation in the context of the recharge oscillator theory is that anomalous easterlies during, e.g. {L}a {N}ina, favour a slow recharge of the equatorial band that will later favour a transition to {E}l {N}ino. {H}ere we demonstrate that {WWV} only works as the best {ENSO} predictor during boreal spring, i.e. during {ENSO} onset, in both observations and {CMIP}5 models. {A}t longer lead times, the heat content in the western {P}acific ({WWVW}) is the best {ENSO} predictor, as initially formulated in the recharge oscillator theory. {U}sing idealised and realistic experiments with a linear continuously stratified ocean model, and a comprehensive wave decomposition method, we demonstrate that spring {WWV} mostly reflects the fast {K}elvin wave response to wind anomalies early in the year, rather than the longer-term influence of winds during the previous year. {WWV} is hence not an adequate index of the slow recharge invoked in the recharge oscillator. {T}he {WWVW} evolution before spring is dominated by forced {R}ossby waves, with a smaller contribution from the western boundary reflection. {WWVW} can be approximated from the integral of equatorial wind stress over the previous similar to 10months, thus involving a longer-term time scale than {WWV} main time scale (similar to 3months). {W}e hence recommend using {WWVW} rather than {WWV} as an index for the slow recharge before the spring predictability barrier.},
  keywords = {{E}l {N}ino {S}outhern {O}scillation ({ENSO}) ; {W}arm {W}ater {V}olume({WWV}) ; {ENSO} ; recharge oscillator ; {E}quatorial {K}elvin and {R}ossby waves ; {ENSO} ; precursors ; {ENSO} conceptual models ; {CMIP}5 climate models ; {PACIFIQUE} ; {ZONE} {EQUATORIALE}},
  booktitle = {},
  journal = {{C}limate {D}ynamics},
  volume = {52},
  numero = {5-6},
  pages = {2923--2942},
  ISSN = {0930-7575},
  year = {2019},
  DOI = {10.1007/s00382-018-4313-1},
  URL = {https://www.documentation.ird.fr/hor/fdi:010075576},
}