@article{fdi:010064096,
  title = {{R}egional equivalent water thickness modeling from remote sensing across a tree cover/lai gradient in mediterranean forests of northern {T}unisia},
  author = {{C}hakroun, {H}. and {M}ouillot, {F}lorent and {H}amdi, {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he performance of vegetation indexes derived from moderate resolution imaging spectroradiometer ({MODIS}) sensors is explored for drought monitoring in the forests of {N}orthern {T}unisia; representing a transition zone between the {M}editerranean {S}ea and the {S}ahara {D}esert. {W}e investigated the suitability of biomass and moisture vegetation indexes for vegetation water content expressed by the equivalent water thickness ({EWT}) in a {M}editerranean forest ecosystem with contrasted water budgets and desiccation rates. {W}e proposed a revised {EWT} at canopy level ({EWTCAN}) based on weekly field measurements of fuel moisture in seven species during the 2010 dry period, considering the mixture of plant functional types for water use (trees, shrubs and herbaceous layers) and a varying vegetation cover. {MODIS} vegetation indexes computed and smoothed over the dry season were highly correlated with the {EWTCAN}. {T}he performances of moisture indexes {N}ormalized {D}ifference {I}nfrared {I}ndex ({NDII}6 and {NDII}7) and {G}lobal {M}oisture {V}egetation {I}ndex ({GVMI}6 and {GVMI}7) were comparable, whereas for biomass vegetation indexes, {N}ormalized {D}ifference {V}egetation {I}ndex ({NDVI}), {M}odified {S}oil {A}djusted {V}egetation {I}ndex ({MSAVI}) and {A}djusted {N}ormalized {D}ifference {V}egetation {I}ndex ({ANDVI}) performed better than {E}nhanced {V}egetation {I}ndex ({EVI}) and {S}oil {A}djusted {V}egetation {I}ndex ({SAVI}). {W}e also identified the effect of {L}eaf {A}rea {I}ndex ({LAI}) on {EWTCAN} monitoring at the regional scale under the tree cover/{LAI} gradient of the region from relatively dense to open forest. {S}tatistical analysis revealed a significant decreasing linear relationship; indicating that for {LAI} less than two, the greater the {LAI}, the less responsive are the vegetation indexes to changes in {EWTCAN}; whereas for higher {LAI}, its influence becomes less significant and was not considered in the inversion models based on vegetation indexes. {T}he {EWTCAN} time-course from {LAI}-adapted inversion models based on significantly-related vegetation indexes to {EWTCAN} showed close profiles resulting from the inversion models using {NDVI}, {ANDVI}, {MSAVI} and {NDII}6 applied during the dry season. {T}he developed {EWTCAN} model from {MODIS} vegetation indexes for the study region was finally tested for its ability to capture the topo-climatic effects on the seasonal and the spatial patterns of desiccation/rewetting for keystone periods of {M}editerranean vegetation functioning. {I}mplications for further use in scientific developments or management are discussed.},
  keywords = {{TUNISIE}},
  booktitle = {},
  journal = {{R}emote {S}ensing},
  volume = {7},
  numero = {2},
  pages = {1937--1961},
  ISSN = {2072-4292},
  year = {2015},
  DOI = {10.3390/rs70201937},
  URL = {https://www.documentation.ird.fr/hor/fdi:010064096},
}