@article{fdi:010066245,
  title = {{U}ncertainty assessment of surface net radiation derived from {L}andsat images},
  author = {{M}ira, {M}. and {O}lioso, {A}. and {G}allego-{E}lvira, {B}. and {C}ourault, {D}. and {G}arrigues, {S}. and {M}arloie, {O}. and {H}agolle, {O}. and {G}uillevic, {P}. and {B}oulet, {G}illes},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he net radiation flux available at the {E}arth's surface drives evapotranspiration, photosynthesis and other physical and biological processes. {T}he only cost-effective way to capture its spatial and temporal variability at regional and global scales is remote sensing. {H}owever, the accuracy of net radiation derived from remote sensing data has been evaluated up to now over a limited number of in situ measurements and ecosystems. {T}his study aims at evaluating estimates and uncertainties on net radiation derived from {L}andsat-7 images depending on reliability of the input surface variables albedo, emissivity and surface temperature. {T}he later includes the reliability of remote sensing information (spectral reflectances and top of canopy brightness temperature) and shortwave and longwave incoming radiations. {P}rimary information describing the surface is derived from remote sensing observations. {S}urface albedo is estimated from spectral reflectances using a narrow-to-broadband conversion method. {L}and surface temperature is retrieved from top of canopy brightness temperature by accounting for land surface emissivity and reflection of atmospheric radiation; and emissivity is estimated using a relationship with a vegetation index and a spectral database of soil and plant canopy properties in the study area. {T}he net radiation uncertainty is assessed using comparison with ground measurements over the {C}rau-{C}amargue and lower {R}hone valley regions in {F}rance. {W}e found {R}oot {M}ean {S}quare {E}rrors between retrievals and field measurements of 0.25-033 (14-19%) for albedo, similar to 1.7 {K} for surface temperature and similar to 20 {W}.m(-2) (5%) for net radiation. {R}esults show a substantial underestimation of {L}andsat-7 albedo (up to 0.024), particularly for estimates retrieved using the middle infrared, which could be due to different sources: the calibration of field sensors, the correction of radiometric signals from {L}andsat-7 or the differences in spectral bands with the sensors for which the models where originally derived, or the atmospheric corrections. {W}e report a global uncertainty in net radiation of 40-100 {W}.m(-2) equally distributed over the shortwave and longwave radiation, which varies spatially and temporally depending on the land use and the time of year. {I}n situ measurements of incoming shortwave and longwave radiation contribute the most to uncertainty in net radiation (10-40 {W}.m(-2) and 20-30 {W}.m(-2), respectively), followed by uncertainties in albedo (<25 {W}.m(-2)) and surface temperature (similar to 8 {W}.m(-2)). {F}or the latter, the main factors were the uncertainties in top of canopy reflectances (<10 {W}.m(-2)) and brightness temperature (5-7 {W}.m(-2)). {T}he generalization of these results to other sensors and study regions could be considered, except for the emissivity if prior knowledge on its characterization is not available.},
  keywords = {{U}ncertainty analysis ; {N}et radiation ; {S}urface temperature ; {A}lbedo ; {E}missivity ; {L}andsat ; {R}egional scale ; {T}emporal course ; {FRANCE}},
  booktitle = {},
  journal = {{R}emote {S}ensing of {E}nvironment},
  volume = {175},
  numero = {},
  pages = {251--270},
  ISSN = {0034-4257},
  year = {2016},
  DOI = {10.1016/j.rse.2015.12.054},
  URL = {https://www.documentation.ird.fr/hor/fdi:010066245},
}