First experiments to determine snow density from diffuse near-infrared transmittance

• Verfasst von: Gergely, Mathias [VerfasserIn]
• Verfasst von: Schneebeli, Martin [VerfasserIn]
• Verfasst von: Roth, Kurt [VerfasserIn]
• Titel: First experiments to determine snow density from diffuse near-infrared transmittance
• Verf.angabe: Mathias Gergely, Martin Schneebeli, Kurt Roth
• E-Jahr: 2010
• Jahr: 23 June 2010
• Umfang: 6 S.
• Fussnoten: Gesehen am 28.02.2023
• Titel Quelle: Enthalten in: Cold regions science and technology
• Ort Quelle: Amsterdam [u.a.] : Elsevier Science, 1979
• Jahr Quelle: 2010
• Band/Heft Quelle: 64(2010), 2, Seite 81-86
• DOI: doi:10.1016/j.coldregions.2010.06.005
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: DISORT
• Sach-SW: Grain size
• Sach-SW: Integrating sphere
• Sach-SW: Snow density
• Sach-SW: Transmittance
• K10plus-PPN: 1837763496

Abstract

Snow density is one of the key properties to characterize a snow cover. We present diffuse near-infrared transmittance measurements with an integrating sphere setup in the laboratory. We analyze 8 snow samples taken from melt forms, decomposed, rounded, faceted and machine made snow. Reference measurements of specific surface area (optically equivalent grain size) and density are done by micro-computed tomography and used as input for transmittance calculations. A diffuse flux extinction model cannot be applied to simulate transmittance as our setup cannot be approximated by an infinite snow block thickness. Calculations with a more intricate radiative transfer model (DISORT) agree with our measurements within the estimated grain size and density variability for all probed natural snow types. Only our machine made snow shows a morphology which cannot be modeled by DISORT. Thus, our results show for the first time a direct experimental correlation between transmittance and snow specific surface area and density without the need for an empirical fitting parameter. We feel this to be an important step towards a possible high-resolution, quantitative optical measurement method to determine snow density in combination with an independent specific surface area measurement.