@article{fdi:010051034,
  title = {{D}ownscaling {MODIS}-derived maps using {GIS} boosted regression trees : the case of frost occurrence over the arid {A}ndean highlands of {B}olivia},
  author = {{P}outeau, {R}obin and {R}ambal, {S}. and {R}atte, {J}.{P}. and {G}og{\'e}, {F}. and {J}offre, {R}ichard and {W}inkel, {T}hierry},
  editor = {},
  language = {{ENG}},
  abstract = {{F}rost risk assessment is of critical importance in tropical highlands like the {A}ndes where human activities thrives at altitudes up to 4200 m, and night frost may occur all the year round. {I}n these semi-arid and cold regions with sparse meteorological networks, remote sensing and topographic modeling are of potential interest for understanding how physiography influences the local climate regime. {A}fter integrating night land surface temperature from the {MODIS} satellite, and physiographic descriptors derived from a digital elevation model, we explored how regional and landscape-scale features influence frost occurrence in the southern altiplano of {B}olivia. {B}ased on the high correlation between night land surface temperature and minimum air temperature, frost occurrence in early-, middle- and late-summer periods were calculated from satellite observations and mapped at a 1-km resolution over a 45,000 km² area. {P}hysiographic modeling of frost occurrence was then conducted comparing multiple regression ({MR}) and boosted regression trees ({BRT}). {P}hysiographic predictors were latitude, elevation, distance from salt lakes, slope steepness, potential insolation, and topographic convergence. {I}nsolation influence on night frost was tested assuming that ground surface warming in the daytime reduces frost occurrence in the next night. {D}epending on the time period and the calibration domain, {BRT} models explained 74% to 90% of frost occurrence variation, outperforming the {MR} method. {I}nverted {BRT} models allowed the downscaling of frost occurrence maps at 100-m resolution, illustrating local processes like cold air drainage. {M}inimum temperature lapse rates showed seasonal variation and mean values higher than those reported for temperate mountains. {W}hen applied at regional and subregional scales successively, {BRT} models revealed prominent effects of elevation, latitude and distance to salt lakes at large scales, whereas slope, topographic convergence and insolation gained influence at local scales. {O}ur results highlight the role of daytime insolation on night frost occurrence at local scale, particularly in the early- and mid-summer periods when solar astronomic forcing is maximum. {S}easonal variations and interactions in physiographic effects are also shown. {N}ested effects of physiographic factors across scales are discussed, as well as potential applications of physiographic modeling to downscale ecological processes in complex terrains. (r{\'e}sum{\'e} d'auteur)},
  keywords = {{AGROCLIMATOLOGIE} ; {HAUTE} {ALTITUDE} ; {TELEDETECTION} {SPATIALE} ; {MODELE} {NUMERIQUE} {DE} {TERRAIN} ; {SYSTEME} {D}'{INFORMATION} {GEOGRAPHIQUE} ; {TOPOGRAPHIE} ; {PENTE} ; {ALTITUDE} ; {TEMPERATURE} {DE} {SURFACE} ; {VARIATION} {SPATIALE} ; {VARIATION} {SAISONNIERE} ; {GELEE} ; {ZONE} {DE} {MONTAGNE} ; {ALTIPLANO} ; {ZONE} {ARIDE} ; {ANDES} ; {BOLIVIE}},
  booktitle = {},
  journal = {{R}emote {S}ensing {E}nvironment},
  volume = {115},
  numero = {1},
  pages = {117--129},
  ISSN = {0034-4257},
  year = {2011},
  DOI = {10.1016/j.rse.2010.08.011},
  URL = {https://www.documentation.ird.fr/hor/fdi:010051034},
}