@article{fdi:010074518,
  title = {{W}estern {P}acific oceanic heat content : a better predictor of {L}a {N}ina than of {E}l {N}ino},
  author = {{P}lanton, {Y}. and {V}ialard, {J}{\'e}r{\^o}me and {G}uilyardi, {E}. and {L}engaigne, {M}atthieu and {I}zumo, {T}akeshi},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he western equatorial {P}acific oceanic heat content (warm water volume in the west or {WWV}w) is the best {E}l {N}ino-{S}outhern {O}scillation ({ENSO}) predictor beyond 1-year lead. {U}sing observations and selected {C}oupled {M}odel {I}ntercomparison {P}roject {P}hase 5 simulations, we show that a discharged {WWV}w in boreal fall is a better predictor of {L}a {N}ina than a recharged {WWV}w for {E}l {N}ino 13 months later, both in terms of occurrence and amplitude. {T}hese results are robust when considering the heat content across the entire equatorial {P}acific ({WWV}) at shorter lead times, including all {C}oupled {M}odel {I}ntercomparison {P}roject {P}hase 5 models or excluding {N}ino-{N}ina and {N}ina-{N}ino phase transitions. {S}uggested mechanisms for this asymmetry include (1) the negatively skewed {WWV}w distribution with stronger discharges related to stronger wind stress anomalies during {E}l {N}ino and (2) the stronger positive {B}jerknes feedback loop during {E}l {N}ino. {T}he possible role of stronger subseasonal wind variations during {E}l {N}ino is also discussed. {P}lain language summary {E}l {N}ino and {L}a {N}ina have strong societal impacts at the global scale, especially large-amplitude {E}l {N}ino events like in 1982-1983, 1997-1998, and 2015-2016. {I}t is hence important to identify early warning signals for the occurrence of {E}l {N}ino/{L}a {N}ina. {T}he equatorial {P}acific {O}cean heat content is a well-known predictor of {E}l {N}ino/{L}a {N}ina several seasons ahead. {I}n this study, we show that negative heat content anomalies lead more systematically to {L}a {N}ina events than positive heat content to {E}l {N}ino events. {W}e suggest that the enhanced predictability of {L}a {N}ina relative to {E}l {N}ino is due to larger negative heat content anomalies ahead of {L}a {N}ina events and a more unstable (and hence less predictable) ocean-atmosphere system during {E}l {N}ino.},
  keywords = {{ENSO} ; predictability ; {E}l {N}ino - {L}a {N}ina asymmetry ; oceanic preconditioning ; warm water volume ; {CMIP}5 ; {PACIFIQUE}},
  booktitle = {},
  journal = {{G}eophysical {R}esearch {L}etters},
  volume = {45},
  numero = {18},
  pages = {9824--9833},
  ISSN = {0094-8276},
  year = {2018},
  DOI = {10.1029/2018gl079341},
  URL = {https://www.documentation.ird.fr/hor/fdi:010074518},
}