@article{PAR00004279,
  title = {{A}ssessing the {SMOS} soil moisture retrieval parameters with high-resolution {NAFE}'06 data},
  author = {{M}erlin, {O}livier and {W}alker, {J}.{P}. and {P}anciera, {R}. and {E}scorihuela, {M}.{J}. and {J}ackson, {T}.{J}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he spatial and temporal invariance of {S}oil {M}oisture and {O}cean {S}alinity ({SMOS}) forward model parameters for soil moisture retrieval was assessed at 1-km resolution on a diurnal basis with data from the {N}ational {A}irborne {F}ield {E}xperiment 2006. {T}he approach used was to apply the {SMOS} default parameters uniformly over 27 1-km validation pixels, retrieve soil moisture from the airborne observations, and then to interpret the differences between airborne and ground estimates in terms of land use, parameter variability, and sensing depth. {F}or pastures ( 17 pixels) and nonirrigated crops ( 5 pixels), the root mean square error (rmse) was 0.03 volumetric (vol./vol.) soil moisture with a bias of 0.004 vol./vol. {F}or pixels dominated by irrigated crops ( 5 pixels), the rmse was 0.10 vol./vol., and the bias was -0.09 vol./vol. {T}he correlation coefficient between bias in irrigated areas and the 1-km field soil moisture variability was found to be 0.73, which suggests either 1) an increase of the soil dielectric roughness ( up to about one) associated with small-scale heterogeneity of soil moisture or/and 2) a difference in sensing depth between an {L}-band radiometer and the in situ measurements, combined with a strong vertical gradient of soil moisture in the top 6 cm of the soil.},
  keywords = {{A}irborne experiment ; calibration ; {L}-band radiometry ; {N}ational {A}irborne ; {F}ield {E}xperiment ({NAFE}) ; retrieval algorithm ; soil moisture ; {S}oil ; {M}oisture and {O}cean {S}alinity ({SMOS})},
  booktitle = {},
  journal = {{IEEE} {G}eoscience and {R}emote {S}ensing {L}etters},
  volume = {6},
  numero = {4},
  pages = {635--639},
  ISSN = {1545-598{X}},
  year = {2009},
  DOI = {10.1109/lgrs.2009.2012727},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00004279},
}