@article{fdi:010085403,
  title = {{A}natomy of the {I}ndian summer monsoon and {ENSO} relationship in a state-of-the-art {CGCM} : role of the tropical {A}tlantic {O}cean},
  author = {{T}erray, {P}ascal and {J}oseph, {L}. and {S}ooraj, {K}. {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he main paradigm for prediction of {I}ndian {S}ummer {M}onsoon {R}ainfall ({ISMR}) is its inverse relation with {E}l {N}ino-{S}outhern {O}scillation ({ENSO}). {I}n this study, we focus on the role of the {A}tlantic {O}cean ({AO}) {S}ea {S}urface {T}emperature ({SST}) variability on the {ISMR}. {T}here are basically two ways by which {AO} {SST}s can impact the {ISMR}: a "direct pathway" in which the {AO} may directly force the {ISMR} in the absence of interactions with other dominant forcings like {ENSO}, and an "indirect pathway" in which {AO} forces {ENSO} and modulates the {ENSO} teleconnection to {ISMR}. {T}hese two pathways are studied with the help of sensitivity experiments performed with a {C}oupled {G}eneral {C}irculation {M}odel. {T}wo pairs of decoupling experiments have been done. {I}n the first, the {SST} variability in the tropical {AO} or {P}acific {O}cean ({PO}) is removed by nudging the {SST} in these regions from a control run's {SST} climatology. {I}n the second set, the {SST} nudging is performed from the observed {SST} climatology, which allows us to assess the robustness of the results and the specific role of the model's {SST} mean-state biases. {T}he direct pathway linking tropical {AO} {SST} variability onto {ISMR} is insignificant in the {PO} decoupled experiments or in recent observations. {F}urthermore, these experiments suggest on the contrary that many {AO} {SST} anomalous patterns could be forced by {ISMR}. {O}n the other hand, for the indirect pathway, the {AO} decoupled experiments demonstrate that {AO} {SST} variability modulates the onset and decaying phases of {ENSO} events. {D}espite {ENSO} is as strong and persists longer than in the control simulation, the {AO} {SST} nudging resulted in a significant weakening of the inverse relationship between {ENSO} and {ISMR}. {T}he {ENSO}-monsoon relationship is mainly modulated during the {ENSO} decaying phase. {T}he upper-level divergent wind flows mainly from the {P}acific to the {AO} resulting in rainfall suppression in the {AO}, but only in a weak forcing on {ISMR} during boreal summer of the {ENSO} decaying year in the {AO} decoupled experiments. {T}hus, the {AO} rainfall variability in these experiments is decoupled from the surface and mainly modulated by the upper-level convergence or divergence induced by the remote {ENSO} forcing. {F}inally, the rectification of the {AO} {SST} mean-state biases in the {CGCM} also induces an {E}l {N}ino-like mean pattern over the tropical {P}acific during boreal spring and promotes a stronger {ENSO} during its peak phase. {T}his demonstrates that the prominent {AO} {SST} mean-state biases in current {CGCM}s further complicate the dynamical prediction and simulation of {ISMR} and {ENSO}.},
  keywords = {{I}ndian summer monsoon ; {E}l {N}ino-{S}outhern {O}scillation ; {T}ropical {A}tlantic {O}cean ; {O}cean-atmosphere interactions ; {W}alker circulation ; {C}oupled climate model ; {ATLANTIQUE} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{C}limate {D}ynamics},
  volume = {[{E}arly access]},
  numero = {},
  pages = {[24 p.]},
  ISSN = {0930-7575},
  year = {2022},
  DOI = {10.1007/s00382-022-06397-9},
  URL = {https://www.documentation.ird.fr/hor/fdi:010085403},
}