Skip to Main content Skip to Navigation
Journal articles

Measurement of vertical profiles of snow specific surface area with a 1 cm resolution using infrared reflectance: instrument description and validation

L. Arnaud 1 G. Picard 2 N. Champollion 2 Florent Domine 3 J. C. Gallet 4 E. Lefebvre 4 M. Fily 2 J.M. Barnola 4
1 EDGe
LGGE - Laboratoire de glaciologie et géophysique de l'environnement
2 CLIPS
LGGE - Laboratoire de glaciologie et géophysique de l'environnement
3 CHANG, CLIPS
LGGE - Laboratoire de glaciologie et géophysique de l'environnement
Abstract : The specific surface area (SSA), defined as the surface area of ice per unit mass, is an important variable characterizing the complex microstructure of snow. Its application range covers the physical evolution of snow (metamorphism), photochemistry and optical and microwave remote sensing. This paper presents a new device, POSSSUM (Profiler Of Snow Specific Surface area Using SWIR reflectance Measurement), designed to allow the rapid acquisition of SSA profiles down to similar to 20 m depth and with an effective vertical resolution of 10-20 mm. POSSSUM is based on the infrared (IR) reflectance technique: A laser diode operating at 1310 nm illuminates the snow at nadir incidence angle along the face of a drilled hole. The reflected radiance is measured at three zenith angles (20 degrees, 40 degrees and 60 degrees) each for two azimuth angles (0 degrees and 180 degrees). A second laser operating at a shorter wavelength (635 nm), which is almost insensitive to SSA, allows the distance to the snow face to be estimated. The reflected IR radiance and the distance are combined to estimate bidirectional reflectances. These reflectances are converted into hemispherical reflectances and in turn into SSA using a theoretical formulation based on an asymptotic solution of the radiative transfer equation. The evaluation and validation of POSSSUM's SSA measurements took place in spring 2009 in the French Alps. The new method was compared with the methane adsorption technique and DUFISSS, another well-validated instrument based on the IR technique. The overall measurement error is in the range 10-15%.
Document type :
Journal articles
Complete list of metadatas

https://hal-insu.archives-ouvertes.fr/insu-00604667
Contributor : Pascale Talour <>
Submitted on : Wednesday, June 29, 2011 - 2:39:40 PM
Last modification on : Friday, September 25, 2020 - 9:16:03 AM

Identifiers

  • HAL Id : insu-00604667, version 1

Collections

Citation

L. Arnaud, G. Picard, N. Champollion, Florent Domine, J. C. Gallet, et al.. Measurement of vertical profiles of snow specific surface area with a 1 cm resolution using infrared reflectance: instrument description and validation. Journal of Glaciology, International Glaciological Society, 2011, 57 (201), pp.17-29. ⟨insu-00604667⟩

Share

Metrics

Record views

186