@article{fdi:010060729,
  title = {{A}ctual evapotranspiration in drylands derived from in-situ and satellite data : assessing biophysical constraints},
  author = {{G}arcia, {M}. and {S}andholt, {I}. and {C}eccato, {P}. and {R}idler, {M}. and {M}ougin, {E}. and {K}ergoat, {L}. and {M}orillas, {L}. and {T}imouk, {F}ranck and {F}ensholt, {R}. and {D}omingo, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}mproving regional estimates of actual evapotranspiration (lambda {E}) in water-limited regions located at climatic transition zones is critical. {T}his study assesses an lambda {E} model ({PT}-{JPL} model) based on downscaling potential evapotranspiration according to multiple stresses at daily time-scale in two of these regions using {MSG}-{SEVIRI} (surface temperature and albedo) and {MODIS} products ({NDVI}, {LAI} and f({PAR})). {A}n open woody savanna in the {S}ahel ({M}ali) and a {M}editerranean grassland ({S}pain) were selected as test sites with {E}ddy {C}ovariance data used for evaluation. {T}he {PT}-{JPL} model was modified to run at a daily time step and the outputs from eight algorithms differing in the input variables and also in the formulation of the biophysical constraints (stresses) were compared with the lambda {E} from the {E}ddy {C}ovariance. {M}odel outputs were also compared with other modeling studies at similar global chyland ecosystems. {T}he novelty of this paper is the computation of a key model parameter, the soil moisture constraint, relying on the concept of apparent thermal inertia (f({SM}-{ATI})) computed with surface temperature and albedo observations. {O}ur results showed that f({SM}-{ATI}) from both in-situ and satellite data produced satisfactory results for lambda {E} at the {S}ahelian savanna, comparable to parameterizations using field-measured {S}oil {W}ater {C}ontent ({SWC}) with r(2) greater than 0.80. {I}n the {M}editerranean grasslands however, with much lower daily lambda {E} values, model results were not as good as in the {S}ahel (r(2)= 0.57-0.31) but still better than reported values from more complex models applied at the site such as the {T}wo {S}ource {M}odel ({TSM}) or the {P}enman-{M}onteith {L}euning model ({PML}). {PT}-{JPL}-daily model with a soil moisture constraint based on apparent thermal inertia, f({SM}-{ATI}) offers great potential for regionalization as no field-calibrations are required and water vapor deficit estimates, required in the original version, are not necessary, being air temperature and the available energy ({R}n-{G}) the only input variables required, apart from routinely available satellite products.},
  keywords = {{E}vapotranspiration ; {S}urface temperature ; {P}riestley-{T}aylor ; {T}hermal inertia ; {MSG}-{SEVIRI} ; {W}ater-limited ecosystems ; {MODIS} ; {MALI}},
  booktitle = {},
  journal = {{R}emote {S}ensing of {E}nvironment},
  volume = {131},
  numero = {},
  pages = {103--118},
  ISSN = {0034-4257},
  year = {2013},
  DOI = {10.1016/j.rse.2012.12.016},
  URL = {https://www.documentation.ird.fr/hor/fdi:010060729},
}