@article{fdi:010048244,
  title = {{R}esponse of surface energy balance to water regime and vegetation development in a {S}ahelian landscape},
  author = {{T}imouk, {F}ranck and {K}ergoat, {L}. and {M}ougin, {E}ric and {L}loyd, {C}. {R}. and {C}eschia, {E}. and {C}ohard, {J}. {M}. and {R}osnay de, {P}. and {H}iernaux, {P}. and {D}emarez, {V}. and {T}aylor, {C}. {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {W}est {A}frican monsoon interacts strongly with the land surface, yet knowledge of these interactions is severely limited by the lack of observations of surface energy fluxes. {W}ithin the framework of the {AMMA} project, three eddy covariance flux stations were installed to sample the three main surface types near {H}ombori ({M}ali) in the central {S}ahel at 15.3 degrees {N}, and a fourth station was installed near {B}amba in the northern {S}ahel at 17.1 degrees {N} to sample semi-desert conditions. {O}bserved land types near {H}ombori comprised a grassland growing on sandy soil (near the village of {A}goufou), a flooded forest in a clay-soil depression ({K}elma), and a bare rocky soil ({E}guerit). {T}he energy balance closure at the grassland site was satisfactory, but less so at the flooded forest site. {S}urface water heat storage during the flood and advection probably were responsible for most of the imbalance. {T}he daily sensible heat flux ({H}) was fairly constant throughout the year at {B}amba and {E}guerit, with only a slight increase during the monsoon season corresponding to increased net radiation. {B}y contrast, the seasonal cycle of the grassland site was marked, with {H} decreasing during the monsoon season from 70 {W} m(-2) in {M}ay to 20 {W} m(-2) in {A}ugust. {T}he flooded woodland exhibited the strongest contrast between the dry and wet seasons, with daily sensible heat flux close to zero during the flood. {D}uring the peak monsoon season, the two vegetated sites had the highest net radiation and the lowest sensible heat flux, as a consequence of the strong evapotranspiration rates caused by both high soil moisture availability and high leaf area index. {L}ateral fluxes of water were found to be strong drivers of inter-site sensible and latent heat fluxes variability, with water leaving bare rocky soils as surface runoff and ending in the clay depressions (e.g., {K}elma), whereas the sandy soils were locally endorheic, with most of the rainfall being rapidly returned to the atmosphere. {A}n attempt was made to scale the sensible heat flux up to the scale of the {AMMA} northern super-site (60 km x 60 km), following a simple scaling scheme, which accounted for the contrasting surface types and water regimes. {T}he super-site average sensible heat flux proved to be close to the grassland sensible heat flux, in part because grassland occupies 55% of the area. {A} strong spatial variability was caused by the difference in water regime and vegetation type, at a scale large enough to potentially influence the atmospheric properties such as the boundary layer.},
  keywords = {{S}ahel ; {S}ensible heat flux ; {L}atent heat flux ; {N}et radiation ; {G}rassland ; {AMMA}},
  booktitle = {},
  journal = {{J}ournal of {H}ydrology},
  volume = {375},
  numero = {1-2},
  pages = {178--189},
  ISSN = {0022-1694},
  year = {2009},
  DOI = {10.1016/j.jhydrol.2009.04.022},
  URL = {https://www.documentation.ird.fr/hor/fdi:010048244},
}