TY - JOUR

T1 - Attenuation of solar radiation in Arctic snow

T2 - Field observations and modelling

AU - Gerland, S.

AU - Liston, G. E.

AU - Winther, J. G.

AU - OrbÆk, J. B.

AU - Ivanov, B. V.

N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2000

Y1 - 2000

N2 - Solar radiation was measured above and in the snowpack on Svalbard using a spectroradiometer and a quantum meter measuring average photosynthetically active radiation (PAR). In order to specify the effect of melting on the snow's radiation properties, all measurements were performed before and during the melt season in May and June 1997 and 1998. Along with the radiation measurements, physical and structural snow properties were logged in snow pits. A physically based model was used to simulate the penetration of radiation into the snow. The model formulation accounts for the spectrally dependent interactions between the radiation and snow grains, and requires inputs of the incoming solar radiation spectrum and the vertical snow density and grain-size. The vertical radiation-flux profile was computed using a two-stream radiation approximation where the absorption and reflection coefficients are related to the surface albedo, solar spectrum, grain-size and number of grains per unit volume. In general, snow before the onset of melt attenuates solar radiation more than coarser-grained snow that has been exposed to melting conditions. Quantum-meter measurements of PAR before and during melt can be explained by model outputs using both constant and variable extinction coefficients. Spectroradiometer measurements at fixed depth levels showed, in addition, that impurities in the snow reduce its transparency and therefore have the opposite effect to aging.

AB - Solar radiation was measured above and in the snowpack on Svalbard using a spectroradiometer and a quantum meter measuring average photosynthetically active radiation (PAR). In order to specify the effect of melting on the snow's radiation properties, all measurements were performed before and during the melt season in May and June 1997 and 1998. Along with the radiation measurements, physical and structural snow properties were logged in snow pits. A physically based model was used to simulate the penetration of radiation into the snow. The model formulation accounts for the spectrally dependent interactions between the radiation and snow grains, and requires inputs of the incoming solar radiation spectrum and the vertical snow density and grain-size. The vertical radiation-flux profile was computed using a two-stream radiation approximation where the absorption and reflection coefficients are related to the surface albedo, solar spectrum, grain-size and number of grains per unit volume. In general, snow before the onset of melt attenuates solar radiation more than coarser-grained snow that has been exposed to melting conditions. Quantum-meter measurements of PAR before and during melt can be explained by model outputs using both constant and variable extinction coefficients. Spectroradiometer measurements at fixed depth levels showed, in addition, that impurities in the snow reduce its transparency and therefore have the opposite effect to aging.

UR - http://www.scopus.com/inward/record.url?scp=0034515983&partnerID=8YFLogxK

U2 - 10.3189/172756400781820444

DO - 10.3189/172756400781820444

M3 - Article

AN - SCOPUS:0034515983

VL - 31

SP - 364

EP - 368

JO - Annals of Glaciology

JF - Annals of Glaciology

SN - 0260-3055

ER -