@article{fdi:010064676,
  title = {{A} snow cover climatology for the {P}yrenees from {MODIS} snow products},
  author = {{G}ascoin, {S}. and {H}agolle, {O}. and {H}uc, {M}. and {J}arlan, {L}ionel and {D}ejoux, {J}. {F}. and {S}zczypta, {C}. and {M}arti, {R}. and {S}anchez, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he seasonal snow in the {P}yrenees is critical for hydropower production, crop irrigation and tourism in {F}rance, {S}pain and {A}ndorra. {C}omplementary to in situ observations, satellite remote sensing is useful to monitor the effect of climate on the snow dynamics. {T}he {MODIS} daily snow products ({T}erra/{MOD}10{A}1 and {A}qua/{MYD}10{A}1) are widely used to generate snow cover climatologies, yet it is preferable to assess their accuracies prior to their use. {H}ere, we use both in situ snow observations and remote sensing data to evaluate the {MODIS} snow products in the {P}yrenees. {F}irst, we compare the {MODIS} products to in situ snow depth ({SD}) and snow water equivalent ({SWE}) measurements. {W}e estimate the values of the {SWE} and {SD} best detection thresholds to 40 mm water equivalent (w.e.) and 150 mm, respectively, for both {MOD}10{A}1 and {MYD}10{A}1. kappa coefficients are within 0.74 and 0.92 depending on the product and the variable for these thresholds. {H}owever, we also find a seasonal trend in the optimal {SWE} and {SD} thresholds, reflecting the hysteresis in the relationship between the depth of the snowpack (or {SWE}) and its extent within a {MODIS} pixel. {T}hen, a set of {L}andsat images is used to validate {MOD}10{A}1 and {MYD}10{A}1 for 157 dates between 2002 and 2010. {T}he resulting accuracies are 97% (kappa = 0.85) for {MOD}10{A}1 and 96% (kappa = 0.81) for {MYD}10{A}1, which indicates a good agreement between both data sets. {T}he effect of vegetation on the results is analyzed by filtering the forested areas using a land cover map. {A}s expected, the accuracies decrease over the forests but the agreement remains acceptable ({MOD}10{A}1: 96 %, kappa = 0.77; {MYD}10{A}1: 95 %, kappa = 0.67). {W}e conclude that {MODIS} snow products have a sufficient accuracy for hydroclimate studies at the scale of the {P}yrenees range. {U}sing a gap-filling algorithm we generate a consistent snow cover climatology, which allows us to compute the mean monthly snow cover duration per elevation band and aspect classes. {T}here is snow on the ground at least 50% of the time above 1600 m between {D}ecember and {A}pril. {W}e finally analyze the snow patterns for the atypical winter 2011-2012. {S}now cover duration anomalies reveal a deficient snowpack on the {S}panish side of the {P}yrenees, which seems to have caused a drop in the national hydropower production.},
  keywords = {{PYRENEES} ; {FRANCE}},
  booktitle = {},
  journal = {{H}ydrology and {E}arth {S}ystem {S}ciences},
  volume = {19},
  numero = {5},
  pages = {2337--2351},
  ISSN = {1027-5606},
  year = {2015},
  DOI = {10.5194/hess-19-2337-2015},
  URL = {https://www.documentation.ird.fr/hor/fdi:010064676},
}