@article{fdi:010073138,
  title = {{A} low-cost albedometer for snow and ice measurements : theoretical results and application on a tropical mountain in {B}olivia [{T}echnical note]},
  author = {{C}ondom, {T}homas and {D}umont, {M}. and {M}ourre, {L}. and {S}icart, {J}ean-{E}mmanuel and {R}abatel, {A}. and {V}iani, {A}. and {S}oruco, {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his study presents a new instrument called a lowcost albedometer ({LCA}) composed of two illuminance sensors that are used to measure in situ incident and reflected illuminance values on a daily timescale. {T}he ratio between reflected vs. incident illuminances is called the albedo index and can be compared with actual albedo values. {D}ue to the shape of the sensor, the direct radiation for zenith angles ranging from 55 to 90 degrees is not measured. {T}he spectral response of the {LCA} varies with the solar irradiance wavelengths within the range 0.26 to 1.195 mu m, and the {LCA} detects 85% of the total spectral solar irradiance for clear sky conditions. {W}e first consider the theoretical results obtained for 10 different ice and snow surfaces with clear sky and cloudy sky incident solar irradiance that show that the {LCA} spectral response may be responsible for an overestimation of the theoretical albedo values by roughly 9% at most. {T}hen, the {LCA} values are compared with two "traditional" albedometers, which are {CM}3 pyranometers ({K}ipp & {Z}onen), in the shortwave domain from 0.305 to 2.800 mu m over a 1-year measurement period (2013) for two sites in a tropical mountainous catchment in {B}olivia. {O}ne site is located on the {Z}ongo {G}lacier (i.e., snow and ice surfaces) and the second one is found on the crest of the lateral moraine (bare soil and snow surfaces), which present a horizontal surface and a sky view factor of 0.98. {T}he results, at daily time steps (256 days), given by the {LCA} are in good agreement with the classic albedo measurements taken with pyranometers with {R}-2 = 0 : 83 ({RMSD} = 0.10) and {R}-2 = 0 : 92 ({RMSD} = 0.08) for the {Z}ongo {G}lacier and the right-hand side lateral moraine, respectively. {T}his demonstrates that our system performs well and thus provides relevant opportunities to document spatiotemporal changes in the surface albedo from direct observations at the scale of an entire catchment at a low cost. {F}inally, during the period from {S}eptember 2015 to {J}une 2016, direct observations were collected with 15 {LCA}s on the {Z}ongo {G}lacier and successfully compared with {LANDSAT} images showing the surface conditions of the glacier (i.e., snow or ice). {T}his comparison illustrates the efficiency of this system to monitor the daily time step changes in the snow and ice coverage distributed on the glacier. {D}espite the limits imposed by the angle view restrictions, the {LCA} can be used between 4 degrees {N} and 45 degrees {S} during the ablation season (spring and summer) when the melt rate related to the albedo is the most important.},
  keywords = {{BOLIVIE} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{G}eoscientific {I}nstrumentation {M}ethods and {D}ata {S}ystems},
  volume = {7},
  numero = {2},
  pages = {169--178},
  ISSN = {2193-0856},
  year = {2018},
  DOI = {10.5194/gi-7-169-2018},
  URL = {https://www.documentation.ird.fr/hor/fdi:010073138},
}