@article{fdi:010054392,
  title = {{T}he {W}est {A}frican monsoon onset in 2006: sensitivity to surface albedo, orography, {SST} and synoptic scale dry-air intrusions using {WRF}},
  author = {{F}laounas, {E}. and {J}anicot, {S}erge and {B}astin, {S}. and {R}oca, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n order to test the sensitivity of the transitional phase of the 2006 {W}est {A}frican monsoon ({WAM}) onset to different mechanisms, weather research and forecasting ({WRF}) model simulations have been carried out addressing the role of the {S}aharan heat low ({SHL}) and its sensitivity to the albedo field and to the northern {A}frica orography, and the role of the sea surface temperature ({SST}) in the eastern tropical {A}tlantic and {M}editerranean. {L}owering albedo over the desert region induces a northward location of the inter-tropical convergence zone ({ITCZ}), while removing mountains in {N}orth {A}frica reduces rainfall over {W}est {A}frica. {S}hifting {SST} forward by 15 days leads to a northward location of the {ITCZ} before the {WAM} onset. {H}owever none of these factors modifies the timing of the {WAM} onset in 2006. {T}he transitional phase of the 2006 {WAM} onset has been examined in more detail. {T}he enhancement of {SHL} intensity, combined with the development of the oceanic cold tongue in the {G}uinea gulf, leads to low-level moisture flux divergence in the {ITCZ} reducing rainfall and increasing low-level humidity over the {S}ahel. {H}owever, weakening of convection can be clearly attributed to dry-air intrusions in mid-levels, originating from the subtropical westerly jet and associated with {R}ossby wave pattern over {N}orth {A}frica. {S}ensitivity tests on the synoptic scale forcing outside of the {WRF} model domain confirm the dominating role of large-scale dynamics to control the transitional phase of the {WAM} onset and its timing. {H}owever it is shown that the regional factors can modulate this larger scale forcing.},
  keywords = {{W}est {A}frican monsoon onset ; {WRF} model ; {D}ry-air intrusions ; {GUINEE} {GOLFE}},
  booktitle = {},
  journal = {{C}limate {D}ynamics},
  volume = {38},
  numero = {3-4},
  pages = {685--708},
  ISSN = {0930-7575},
  year = {2012},
  DOI = {10.1007/s00382-011-1255-2},
  URL = {https://www.documentation.ird.fr/hor/fdi:010054392},
}