@article{fdi:010055778,
  title = {{T}he role of the {I}ndian monsoon onset in the {W}est {A}frican monsoon onset : observations and {AGCM} nudged simulations},
  author = {{F}laounas, {E}. and {J}anicot, {S}erge and {B}astin, {S}. and {R}oca, {R}. and {M}ohino, {E}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n spring the inland penetration of the {W}est {A}frican {M}onsoon ({WAM}) is weak and the associated rainband is located over the {G}uinean coast. {T}hen within a few days deep convection weakens considerably and the rainband reappears about 20 days after over the {S}ahel, where it remains until late {S}eptember signalling the summer rainy season. {O}ver the period 1989-2008 a teleconnection induced by the {I}ndian monsoon onset is shown to have a significant impact on the {WAM} onset, by performing composite analyses on both observational data sets and atmospheric general circulation model simulations ensembles where the model is nudged to observations over the {I}ndian monsoon sector. {T}he initiation of convective activity over the {I}ndian subcontinent north of 15 degrees {N} at the time of the {I}ndian monsoon onset results in a westward propagating {R}ossby wave establishing over {N}orth {A}frica 7-15 days after. {A} back-trajectory analysis shows that during this period, dry air originating from the westerly subtropical jet entrance is driven to subside and move southward over {W}est {A}frica inhibiting convection there. {A}t the same time the low-level pressure field over {W}est {A}frica reinforces the moisture transport inland. {A}fter the passage of the wave, the dry air intrusions weaken drastically. {H}ence 20 days after the {I}ndian monsoon onset, convection is released over the {S}ahel where thermodynamic conditions are more favourable. {T}his scenario is very similar in the observations and in the nudged simulations, meaning that the {I}ndian monsoon onset is instrumental in the {WAM} onset and its predictability at intraseasonal scale.},
  keywords = {{W}est {A}frican monsoon onset ; {I}ndian monsoon onset ; {D}ry-air intrusions ; {M}adden-{J}ulian ; {O}scillation ; {A}tmospheric general circulation models ; {N}udging},
  booktitle = {},
  journal = {{C}limate {D}ynamics},
  volume = {38},
  numero = {5-6},
  pages = {965--983},
  ISSN = {0930-7575},
  year = {2012},
  DOI = {10.1007/s00382-011-1045-x},
  URL = {https://www.documentation.ird.fr/hor/fdi:010055778},
}