@incollection{fdi:010072211,
  title = {{S}ubsurface hydrology of the {L}ake {C}had {B}asin from convection modelling and observations},
  author = {{L}opez, {T}. and {A}ntoine, {R}. and {K}err, {Y}. and {D}arrozes, {J}. and {R}abinowicz, {M}. and {R}amillien, {G}. and {C}azenave, {A}. and {G}enthon, {P}ierre},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n the {L}ake {C}had basin, the quaternary phreatic aquifer (named hereafter {QPA}) presents large piezometric anomalies referred to as domes and depressions whose depths are * 15 and * 60 m, respectively. {A} previous study ({L}eblanc et al. in {G}eophys {R}es {L}ett, 2003, doi: 10.1029/2003{GL}018094) noticed that brightness temperatures from {METEOSAT} infrared images of the {L}ake {C}had basin are correlated with the {QPA} piezometry. {I}ndeed, at the same latitude, domes are * 4-5 {K} warmer than the depressions. {L}eblanc et al. ({G}eophys {R}es {L}ett, 2003, doi: 10.1029/2003{GL}018094) suggested that such a thermal behaviour results from an evapotranspiration excess above the piezometric depressions, an interpretation implicitly assuming that the {QPA} is separated from the other aquifers by the clay-rich {P}liocene formation. {B}ased on satellite visible images, here we find evidence of giant polygons, an observation that suggests instead a local vertical connectivity between the different aquifers. {W}e developed a numerical water convective model giving an alternative explanation for the development of {QPA} depressions and domes. {B}eneath the depressions, a cold descending water convective current sucks down the overlying {QPA}, while, beneath the dome, a warm ascending current produces overpressure. {S}uch a basinwide circulation is consistent with the water geochemistry. {W}e further propose that the thermal diurnal and evaporation/condensation cycles specific to the water ascending current explain why domes are warmer. {W}e finally discuss the possible influence of the inferred convective circulation on the transient variations of the {QPA} reported from observations of piezometric levels and {GRACE}-based water mass change over the region.},
  keywords = {{TCHAD} ; {NIGERIA} ; {NIGER} ; {SAHEL} ; {TCHAD} {LAC} {BASSIN}},
  booktitle = {{R}emote sensing and water resources},
  numero = {55},
  pages = {281--312},
  address = {{C}ham},
  publisher = {{S}pringer},
  series = {{S}pace {S}ciences {S}eries of {ISS}},
  year = {2016},
  DOI = {10.1007/978-3-319-32449-4_12},
  ISBN = {978-3-319-32448-7},
  URL = {https://www.documentation.ird.fr/hor/fdi:010072211},
}