@article{fdi:010074362,
  title = {{P}otential impacts of land cover change on the interannual variability of rainfall and surface temperature over {W}est {A}frica},
  author = {{D}iba, {I}. and {C}amara, {M}. and {S}arr, {A}. {B}. and {D}iedhiou, {A}rona},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e used the {A}bdu {S}alam {I}nternational {C}entre for {T}heoretical {P}hysics ({ICTP}) {R}egional {C}limate {M}odel version 4.5 ({R}eg{CM}4.5), to investigate the potential impacts of land cover change of the {S}ahel-{S}ahara interface on the {W}est {A}frican climate over an interannual timescale from 1990 to 2009. {A} simulation at 50 km grid spacing is performed with the standard version of the {R}eg{CM}4.5 model (control run), followed by three vegetation change experiments at the {S}ahel-{S}ahara interface (15 degrees {N} and 20 degrees {N}): forest, tall grass, and short grass savanna. {T}he impacts of land cover change are assessed by analyzing the difference between the altered runs and the control one in different sub-domains (western {S}ahel, central {S}ahel, eastern {S}ahel, and {G}uinea). {R}esults show that the presence of forest, tall grass, and short grass savanna at the {S}ahel-{S}ahara interface tends to decrease the mean summer surface temperature in the whole domain. {N}evertheless, this decrease is more pronounced over the {C}entral {S}ahel when considering the forest experiment. {T}his temperature decrease is associated with a weakening (strengthening) of the sensible (latent) heat flux in the whole domain. {A}n analysis of the radiation field is performed to better explain the changes noted in the latent heat flux, the sensible heat flux, and the surface temperature. {W}hen considering the rainfall signal, the analysis shows that the afforestation options tend to alter the precipitation in the considered sub-domains substantially by increasing it in the whole {S}ahel region, with strong interannual variability. {T}his rainfall increase is associated with an increase of the atmospheric moisture. {F}inally, we investigated the impacts of the afforestation options on some features of the rainfall events, and on the atmospheric dynamics during wet and dry years. {A}ll afforestation options tend to increase the frequency of the number of rainy days in regions located south of 18 degrees {N} during both periods. {N}evertheless, this increase is stronger over the {C}entral and {E}astern {S}ahel during wet years in the forest case. {A}ll afforestation experiments induce an increase (decrease) of the low-levels monsoon flux in the {E}astern {S}ahel (western {S}ahel) during both periods. {A}t the mid-levels, the three afforestation options tend to move northward and to decrease the intensity of the {A}frican {E}asterly {J}et ({AEJ}) south of 13 degrees {N} during wet and dry years.{T}he intensity of the {AEJ} is weaker during the wet period. {T}he vegetation change experiments also affect the {T}ropical {E}asterly {J}et ({TEJ}), especially during wet years, by increasing its intensity over the southern {S}ahel. {T}he analysis of the activity of {A}frican {E}asterly {W}aves ({AEW}s) patterns exhibits a decrease of the intensity of these disturbances over the {S}ahel during both periods. {T}his may be due to the weakening of the meridional temperature contrast between the continent and the {G}ulf of {G}uinea due to the {S}ahel-{S}ahara surface temperature cooling induced by the afforestation. {I}n summary, this study shows that during both periods, the increase of the atmospheric moisture due to the afforestation is associated with favorable {AEJ}/{TEJ} configurations (weaker and northward position of the {AEJ}; stronger {TEJ}) which in turn may create a stronger convection and then, an increase in the {S}ahel rainfall. {T}his {S}ahel rainfall increase is associated with a strengthening of the intense and heavy rainfall events which may impact diversely local populations.},
  keywords = {{R}eg{CM}4 ; reforestation ; rainfall ; temperature ; wind dynamics ; interannual ; variability ; {W}est {A}frica ; {AFRIQUE} {DE} {L}'{OUEST} ; {ZONE} {SAHELIENNE} ; {ZONE} {GUINEENNE} ; {SAHARA}},
  booktitle = {},
  journal = {{A}tmosphere},
  volume = {9},
  numero = {10},
  pages = {art. 376 [32 p.]},
  ISSN = {2073-4433},
  year = {2018},
  DOI = {10.3390/atmos9100376},
  URL = {https://www.documentation.ird.fr/hor/fdi:010074362},
}