@article{PAR00011390,
  title = {{C}omparison between {SMOS} {V}egetation {O}ptical {D}epth products and {MODIS} vegetation indices over crop zones of the {USA}},
  author = {{L}awrence, {H}. and {W}igneron, {J}. {P}. and {R}ichaume, {P}. and {N}ovello, {N}. and {G}rant, {J}. and {M}ialon, {A}. and {A}l {B}itar, {A}. and {M}erlin, {O}livier and {G}uyon, {D}. and {L}eroux, {D}. and {B}ircher, {S}. and {K}err, {Y}ann},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {S}oil {M}oisture and {O}cean {S}alinity ({SMOS}) mission provides multi-angular, dual-polarised brightness temperatures at 1.4 {GH}z, from which global soil moisture and vegetation optical depth (tau) products are retrieved. {T}his paper presents a study of {SMOS}' tau product in 2010 and 2011 for crop zones of the {USA}. {R}etrieved tau values for 504 crop nodes were compared to optical/{IR} vegetation indices from the {MODES} ({M}oderate {R}esolution {I}maging {S}pectroradiometer) satellite sensor, including the {N}ormalised {D}ifference {V}egetation {I}ndex ({NDVI}), {E}nhanced {V}egetation {I}ndex ({EVE}), {L}eaf {A}rea {I}ndex ({LAI}), and a {N}ormalised {D}ifference {W}ater {I}ndex ({NOW}!) product. tau values were observed to increase during the growing season and decrease during senescence in these areas, as did {MODIS} vegetation indices. {SMOS}' tau values generally peaked later than {MODES} {LAI} values, with an estimated time difference of about 19 days. {A} linear regression between tau and the {MODIS} products was carried out for each node and values of the determination coefficient, {R}-2, slope, b' and intercept, b ' were found. {T}he average {R}-2 value varied from 0.32 to 035 for the different vegetation indices. {T}he linear regression between {LAI} and tau produced an average slope of b' = 0.06, and an average intercept of b ' = 0.14. {T}he effects of crop fraction and dominant crop type were investigated and crop fraction was found to have a low effect on {R}-2 values. {R}-2 values appeared to be lower for wheat and hay and higher for corn. b' and b ' values had higher standard deviations for wheat but were generally close to the mean values for corn, soybean and hay.},
  keywords = {{SMOS} ; {V}egetation optical depth ; {L}-band radiometry ; {O}ptical vegetation indices ; {ETATS} {UNIS}},
  booktitle = {},
  journal = {{R}emote {S}ensing of {E}nvironment},
  volume = {140},
  numero = {},
  pages = {396--406},
  ISSN = {0034-4257},
  year = {2014},
  DOI = {10.1016/j.rse.2013.07.021},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00011390},
}