@article{fdi:010080662,
  title = {{T}emporal mosaicking approaches of {S}entinel-2 images for extending topsoil organic carbon content mapping in croplands},
  author = {{V}audour, {E}. and {G}omez, {C}{\'e}cile and {L}agacherie, {P}. and {L}oiseau, {T}. and {B}aghdadi, {N}. and {U}rbina-{S}alazar, {D}. and {L}oubet, {B}. and {A}rrouays, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he spatial assessment of soil organic carbon ({SOC}) is a major environmental challenge, notably for evaluating soil carbon stocks. {R}ecent works have shown the capability of {S}entinel-2 to predict {SOC} content over temperate agroecosystems characterized with annual crops. {H}owever, because spectral models are only applicable on bare soils, the mapping of {SOC} is often obtained on limited areas. {A} possible improvement for increasing the number of pixels on which {SOC} can be retrieved by inverting bare soil reflectance spectra, consists of using optical images acquired at several dates. {T}his study compares different approaches of {S}entinel-2 images temporal mosaicking to produce a composite multi-date bare soil image for predicting {SOC} content over agricultural topsoils. {A} first approach for temporal mosaicking was based on a per-pixel selection and was driven by soil surface characteristics: bare soil or dry bare soil with/without removing dry vegetation. {A} second approach for creating composite images was based on a per-date selection and driven either by the models performance from single date, or by average soil surface indicators of bare soil or dry bare soil. {T}o characterize soil surface, {S}entinel-1 ({S}1)-derived soil moisture and/or spectral indices such as normalized difference vegetation index ({NDVI}), {N}ormalized {B}urn {R}atio 2 ({NBR}2), bare soil index ({BSI}) and a soil surface moisture index ({S}2{WI}) were used either separately or in combination. {T}his study highlighted the following results: i) none of the temporal mosaic images improved model performance for {SOC} prediction compared to the best single-date image; ii) of the per-pixel approaches, temporal mosaics driven by the {S}1-derived moisture content, and to a lesser extent, by {NBR}2 index, outperformed the mosaic driven by the {BSI} index but they did not increase the bare soil area predicted; iii) of the per-date approaches, the best trade-off between predicted area and model performance was achieved from the temporal mosaic driven by the {S}1-derived moisture content ({R}-2 similar to 0.5, {RPD} similar to 1.4, {RMSE} similar to 3.7 g.kg(-1)) which enabled to more than double (*2.44) the predicted area. {T}his study suggests that a number of bare soil mosaics based on several indicators (moisture, bare soil, roughness...), preferably in combination, might maintain acceptable accuracies for {SOC} prediction whilst extending over larger areas than single-date images.},
  keywords = {{S}oil organic carbon ; {S}entinel-2 ; {T}emporal mosaic ; {C}roplands ; {S}oil moisture ; {FRANCE} ; {VERSAILLES} {PLAINE}},
  booktitle = {},
  journal = {{I}nternational {J}ournal of {A}pplied {E}arth {O}bservation and {G}eoinformation},
  volume = {96},
  numero = {},
  pages = {102277 [18 p.]},
  ISSN = {1569-8432},
  year = {2021},
  DOI = {10.1016/j.jag.2020.102277},
  URL = {https://www.documentation.ird.fr/hor/fdi:010080662},
}