Relationship between the Concentration of Impurity and Albedo in Snow Surface

Abstract

Recent decline of cryosphere typified by retreat of glaciers is often explained by temperature rise due to global warming. However, the existence of glaciers shrinking since before 1950s warming accelerated suggested that decline of cryosphere may be due to not only temperature rise, but also another possibility. As a possible cause of snow and ice melting, it has been pointed out that the surface albedo reduction due to increase of snow impurity, aeolian dust and anthropogenic pollutant, for example. To clarify the quantitative relationship between albedo and impurity in snow surface, we investigated the correlativity of turbidity and metal concentration in snow to the snow surface albedo from the simultaneous observations on the snow-covered area in Yamagata, Japan. The observed albedo shows a tendency of decrease with the turbidity increase in snow surface, we could find strong correlation between the albedo and the turbidity in 76% of contribution factor using logarithmic regression analysis. The relationship of albedo to total concentration of Fe and Al in snow surface shows the similar tendency to turbidity, we could model the relationship using logarithmic equation with high value of contribution ratio, 74% and 66%, respectively. The concentration ratio of Fe/Al is nearly constant with about 0.75, which is close to mean crustal ratio of both elements, therefore, it can be said there is a strong correlation between the albedo and the concentration of mineral particle in snow surface. We cannot find a significant correlation between the albedo and total concentration of Na in snow surface. It can be considered that Na existed as dissolved ion has not significant effect to the albedo in snow surface. These results indicate that the snow albedo correlates strongly with the particulate matter in snow surface, which is typified by mineral particle.

Effect of small-scale snow surface roughness on snow albedo and reflectance

“…So far, the scanners with the highest point density, accuracy and smallest spot size are meant for indoor use, but as the technology improves, smaller and smaller features become measurable also outdoors. In addition, the fractal nature of snow surfaces enables extrapolation of surface roughness from the centimetre scale to the millimetre scale (Kukko et al, 2013). Another benefit of using laser scanning for surface roughness measurements is that it leaves the surface intact.…”

“…In addition to the plate measurements, laser scanning data for snow roughness were utilized. The laser scanning data used in this study have been acquired using the FGI ROAMER system (Kukko et al, 2007). The system, including a FARO Photon 120 laser scanner, a NovAtel SPAN GPS-IMU system, and data synchronizing and recording devices, was mounted on a sledge, which was towed by a snowmobile.…”

“…The system, including a FARO Photon 120 laser scanner, a NovAtel SPAN GPS-IMU system, and data synchronizing and recording devices, was mounted on a sledge, which was towed by a snowmobile. The data acquisition covers a 2.5 km zone at each side of an official snowmobile track (see Kukko et al, 2013, for examples of profiles, the snowmobile track and other details). The landscape covered sparse pine forests and open bogs.…”

“…The laser scanning data covered a 2.4 km long and about 3.2 m wide area on each side of the snowmobile route. Altogether 10 plate profile measurements were taken directly after the scanning, at about 100-200 m intervals starting from the western edge of the scan route (Kukko et al, 2013). The average rms slope angle of the 10 plate profiles was Figure 7.…”

Effect of small-scale snow surface roughness on snow albedo and reflectance

“…Light attenuation within the snowpack is related to the density of the scattering elements per unit volume. In addition, layer structure, grain shape, anthropogenic and natural impurities (such as black carbon, dust and algae) and close-packing effects of snow grains affect scattering properties and thus, the albedo of a snowpack (Warren and Wiscombe, 1980;Kokhanovsky and Zege, 2004;Aoki et al, 2011;Kokhanovsky, 2013;Libois et al, 2013;Libois et al, 2014;Komuro and Suzuki, 2015;Peltoniemi et al, 2015;Pirazzini et al, 2015;Räisänen et al, 2015;Cook et al, 2017;He et al, 2017, Kokhanovsky et al, 2018. Several models for the coupled mass and energy balances of snow on the ground have also been developed (Flanner and Zender, 2006;Essery, 2015).…”