@article{fdi:010079841,
  title = {{A}natomy of the {I}ndian summer monsoon and {ENSO} relationships in state-of-the-art {CGCM}s : role of the tropical {I}ndian {O}cean},
  author = {{T}erray, {P}ascal and {S}ooraj, {K}. {P}. and {M}asson, {S}. and {P}rodhomme, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}ndian {S}ummer {M}onsoon ({ISM}) rainfall and {E}l {N}ino-{S}outhern {O}scillation ({ENSO}) exhibit an inverse relationship during boreal summer, which is one of the roots of {ISM} interannual variability and its seasonal predictability. {H}ere we document how current climate and seasonal prediction models simulate the timing and amplitude of this {ISM}-{ENSO} teleconnection. {M}any {C}oupled {G}eneral {C}irculation {M}odels ({CGCM}s) do simulate a simultaneous inverse relationship between {ENSO} and {ISM}, though with a large spread. {H}owever, most of them show significant negative correlations before {ISM}, which are at odd with observations. {C}onsistent with this systematic error, simulated {N}ino-3.4 {S}ea {S}urface {T}emperature ({SST}) variability has erroneous high amplitude during boreal spring and {ISM} rainfall variability is also too strong during the first part of {ISM}. {T}he role of the {I}ndian {O}cean ({IO}) in modulating the {ISM}-{ENSO} relationships is further investigated using dedicated experiments with the {SINTEX}-{F}2 {CGCM}. {D}ecoupled tropical {P}acific and {IO} experiments are conducted to assess the direct relationship between {ISM} and {IO} {SST}s on one hand, and the specific role of {IO} feedback on {ENSO} on the other hand. {T}he direct effect of {IO} {SST}s on {ISM} is weak and insignificant at the interannual time scale in the {P}acific decoupled experiment. {O}n the other hand, {IO} decoupled experiments demonstrate that {E}l {N}ino shifts rapidly to {L}a {N}ina when ocean-atmosphere coupling is active in the whole {IO} or only in its western part. {T}his {IO} negative feedback is mostly active during the decaying phase of {E}l {N}ino, which is accompanied by a basin-wide warming in the {IO}, and significantly modulates the length of {ENSO} events in our simulations. {T}his {IO} feedback operates through a modulation of the {W}alker circulation over the {IO}, which strengthens and shifts eastward an anomalous anticyclone centered on the {P}hilippine {S}ea and associated easterly wind anomalies in the equatorial western {P}acific during boreal winter. {I}n turn, these atmospheric anomalies lead to a fast {ENSO} turnabout via oceanic adjustement processes mediated by eastward propagating upwelling {K}elvin waves. {A}n experiment in which only the {S}outh{E}ast {I}ndian {O}cean ({SEIO}) is decoupled, demonstrates that the equatorial {SST} gradient in the {IO} during boreal winter plays a fundamental role in the efficiency of {IO} feedback. {I}n this experiment, simulated {ISM}-{ENSO} lead-lag correlations match closely the observations. {T}his success is associated with removal of erroneous {SEIO} {SST} variability during boreal winter in the {SEIO} decoupled experiment. {F}inally, it is illustrated that most {CMIP}5 {CGCM}s exhibit similar {SST} errors in the {SEIO} during boreal winter in addition to an exagerated {SEIO} {SST} variability during boreal fall.},
  keywords = {{I}ndian summer monsoon ; {E}l nino-southern oscillation ; {I}ndian ocean ; {O}cean-atmosphere interactions ; {C}oupled climate model ; {OCEAN} {INDIEN} ; {INDE}},
  booktitle = {},
  journal = {{C}limate {D}ynamics},
  volume = {56},
  numero = {1-2},
  pages = {329--356},
  ISSN = {0930-7575},
  year = {2021},
  DOI = {10.1007/s00382-020-05484-z},
  URL = {https://www.documentation.ird.fr/hor/fdi:010079841},
}