@article{fdi:010062714,
  title = {{I}rrigated grassland monitoring using a time series of {T}erra{SAR}-{X} and {COSMO}-{S}ky{M}ed {X}-band {SAR} data},
  author = {{E}l {H}ajj, {M}. and {B}aghdadi, {N}. and {B}elaud, {G}. and {Z}ribi, {M}ehrez and {C}heviron, {B}. and {C}ourault, {D}. and {H}agolle, {O}. and {C}harron, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he objective of this study was to analyze the sensitivity of radar signals in the {X}-band in irrigated grassland conditions. {T}he backscattered radar signals were analyzed according to soil moisture and vegetation parameters using linear regression models. {A} time series of radar ({T}erra{SAR}-{X} and {COSMO}-{S}ky{M}ed) and optical ({SPOT} and {LANDSAT}) images was acquired at a high temporal frequency in 2013 over a small agricultural region in southeastern {F}rance. {G}round measurements were conducted simultaneously with the satellite data acquisitions during several grassland growing cycles to monitor the evolution of the soil and vegetation characteristics. {T}he comparison between the {N}ormalized {D}ifference {V}egetation {I}ndex ({NDVI}) computed from optical images and the in situ {L}eaf {A}rea {I}ndex ({LAI}) showed a logarithmic relationship with a greater scattering for the dates corresponding to vegetation well developed before the harvest. {T}he correlation between the {NDVI} and the vegetation parameters ({LAI}, vegetation height, biomass, and vegetation water content) was high at the beginning of the growth cycle. {T}his correlation became insensitive at a certain threshold corresponding to high vegetation ({LAI} similar to 2.5 m(2)/m(2)). {R}esults showed that the radar signal depends on variations in soil moisture, with a higher sensitivity to soil moisture for biomass lower than 1 kg/m(2). {HH} and {HV} polarizations had approximately similar sensitivities to soil moisture. {T}he penetration depth of the radar wave in the {X}-band was high, even for dense and high vegetation; flooded areas were visible in the images with higher detection potential in {HH} polarization than in {HV} polarization, even for vegetation heights reaching 1 m. {L}ower sensitivity was observed at the {X}-band between the radar signal and the vegetation parameters with very limited potential of the {X}-band to monitor grassland growth. {T}hese results showed that it is possible to track gravity irrigation and soil moisture variations from {SAR} {X}-band images acquired at high spatial resolution (an incidence angle near 30 degrees).},
  keywords = {grassland ; irrigation ; {T}erra{SAR}-{X} ; {COSMO}-{S}ky{M}ed ; {SPOT}-4 ; {LANDSAT} ; soil moisture ; vegetation parameters ; {FRANCE}},
  booktitle = {},
  journal = {{R}emote {S}ensing},
  volume = {6},
  numero = {10},
  pages = {10002--10032},
  ISSN = {2072-4292},
  year = {2014},
  DOI = {10.3390/rs61010002},
  URL = {https://www.documentation.ird.fr/hor/fdi:010062714},
}