@article{fdi:010089727,
  title = {{R}etrieving the irrigation actually applied at district scale : assimilating high-resolution {S}entinel-1-derived soil moisture data into a {FAO}-56-based model},
  author = {{L}aluet, {P}. and {O}livera-{G}uerra, {L}. {E}. and {A}lt{\'e}s, {V}. and {P}aolini, {G}. and {O}uaadi, {N}. and {R}ivalland, {V}. and {J}arlan, {L}ionel and {V}illar, {J}. {M}. and {M}erlin, {O}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}rrigation is the most water consuming activity in the world. {K}nowing the timing and amount of irrigation that is actually applied is therefore fundamental for water managers. {H}owever, this information is rarely available at all scales and is subject to large uncertainties due to the wide variety of existing agricultural practices and associated irrigation regimes (full irrigation, deficit irrigation, or over -irrigation). {T}o fill this gap, we propose a two-step approach based on 15 m resolution {S}entinel -1 ({S}1) surface soil moisture ({SSM}) data to retrieve the actual irrigation at the weekly scale over an entire irrigation district. {I}n a first step, the {S}1 -derived {SSM} is assimilated into a {FAO} -56 -based crop water balance model ({SAMIR}) to retrieve for each crop type both the irrigation amount ({I}dose) and the soil moisture threshold ({SM}threshold) at which irrigation is triggered. {T}o do this, a particle filter method is implemented, with particles reset each month to provide time -varying {SM}threshold and {I}dose. {I}n a second step, the retrieved {SM}threshold and {I}dose values are used as input to {SAMIR} to estimate the weekly irrigation and its uncertainty. {T}he assimilation approach ({SSM}-{ASSIM}) is tested over the 8000 hectare {A}lgerri-{B}alaguer irrigation district located in northeastern {S}pain, where in situ irrigation data integrating the whole district are available at the weekly scale during 2019. {F}or evaluation, the performance of {SSM}-{ASSIM} is compared with that of the default {FAO} -56 irrigation module (called {FAO}56-{DEF}), which sets the {SM}threshold to the critical soil moisture value and systematically fills the soil reservoir for each irrigation event. {I}n 2019, with an observed annual irrigation of 687 mm, {SSM}-{ASSIM} ({FAO}56-{DEF}) shows a root mean square deviation between retrieved and in situ irrigation of 6.7 (8.8) mm week -1, a bias of +0.3 (-1.4) mm week -1, and a {P}earson correlation coefficient of 0.88 (0.78). {T}he {SSM}-{ASSIM} approach shows great potential for retrieving the weekly water use over extended areas for any irrigation regime, including over -irrigation.},
  keywords = {{I}rrigation amounts ; {D}ata assimilation ; {S}oil moisture ; {W}ater balance model ; {R}emote sensing ; {M}icrowave ; {ESPAGNE} ; {ZONE} {MEDITERRANEENNE}},
  booktitle = {},
  journal = {{A}gricultural {W}ater {M}anagement},
  volume = {117},
  numero = {},
  pages = {108704 [17 p.]},
  ISSN = {0898-6568},
  year = {2024},
  URL = {https://www.documentation.ird.fr/hor/fdi:010089727},
}