@article{fdi:010082579,
  title = {{I}rrigation amounts and timing retrieval through data assimilation of surface soil moisture into the {FAO}-56 approach in the {S}outh {M}editerranean region},
  author = {{O}uaadi, {N}. and {J}arlan, {L}ionel and {K}habba, {S}. and {E}zzahar, {J}. and {L}e {P}age, {M}ichel and {M}erlin, {O}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}gricultural water use represents more than 70% of the world's freshwater through irrigation water inputs that are poorly known at the field scale. {I}rrigation monitoring is thus an important issue for optimizing water use in particular with regards to the water scarcity that the semi-arid regions are already facing. {I}n this context, the aim of this study is to develop and evaluate a new approach to predict seasonal to daily irrigation timing and amounts at the field scale. {T}he method is based on surface soil moisture ({SSM}) data assimilated into a simple land surface ({FAO}-56) model through a particle filter technique based on an ensemble of irrigation scenarios. {T}he approach is implemented in three steps. {F}irst, synthetic experiments are designed to assess the impact of the frequency of observation, the errors on {SSM} and the a priori constraints on the irrigation scenarios for different irrigation techniques (flooding and drip). {I}n a second step, the method is evaluated using in situ {SSM} measurements with different revisit times (3, 6 and 12 days) to mimic the available {SSM} product derived from remote sensing observation. {F}inally, {SSM} estimates from {S}entinel-1 are used. {D}ata are collected on different wheat fields grown in {M}orocco, for both flood and drip irrigation techniques in addition to rainfed fields used for an indirect evaluation of the method performance. {U}sing in situ data, accurate results are obtained. {W}ith an observation every 6 days to mimic the {S}entinel-1 revisit time, the seasonal amounts are retrieved with {R} > 0.98, {RMSE} < 32 mm and bias < 2.5 mm. {L}ikewise, a good agreement is observed at the daily scale for flood irrigation as more than 70% of the detected irrigation events have a time difference from actual irrigation events shorter than 4 days. {O}ver the drip irrigated fields, the statistical metrics are {R} = 0.74, {RMSE} = 24.8 mm and bias = 2.3 mm for irrigation amounts cumulated over 15 days. {W}hen using {SSM} products derived from {S}entinel-1 data, the statistical metrics on 15-day cumulated amounts slightly dropped to {R} = 0.64, {RMSE} = 28.7 mm and bias = 1.9 mm. {T}he metrics on the seasonal amount retrievals are close to assimilating in situ observations with {R} = 0.99, {RMSE} = 33.5 mm and bias = -18.8 mm. {F}inally, among four rainfed seasons, only one false event was detected. {T}his study opens perspectives for the regional retrieval of irrigation amounts and timing at the field scale and for mapping irrigated/non irrigated areas.},
  keywords = {{ZONE} {MEDITERRANEENNE} ; irrigation timing and amounts ; surface soil moisture ; data assimilation ; particle filters ; {FAO}-56 ; {S}entinel-1 ; semi-arid {M}editerranean region ; winter wheat ; {MAROC}},
  booktitle = {},
  journal = {{R}emote {S}ensing},
  volume = {13},
  numero = {14},
  pages = {2667 [26 ]},
  year = {2021},
  DOI = {10.3390/rs13142667},
  URL = {https://www.documentation.ird.fr/hor/fdi:010082579},
}