Mineral dust layers in snow at Mount Tateyama, Central Japan: formation processes and characteristics

Abstract

Deposition of water‐insoluble dust was measured in winter snow deposited at Murododaira (2450 m) on the western flank of Mount Tateyama in central Japan. An analysis of temporal variation in atmospheric aerosol concentration, incremental snow height and concentration of dust in the snow cover suggests that wet deposition is the major process in forming thicker dust layers in the snow cover at Mount Tateyama. Dust layers in the snow cover contain Ca‐rich materials typically found in Asian dust (Kosa) particles. Volume size distributions of dust particles in the snow showed single and bi‐modal structures having volume median diameters from 6–21 μm. Dust profiles in snow cover over the last 6 yr reveal frequent sporadic high dust concentrations in spring and large year‐to‐year variations in the amount deposited. The average amount of dust deposition (7.7 g m−2) from winter to spring at the site was close to the long‐term averages of annual flux obtained from sea sediment near Japan, implying that dusty precipitation in spring contributes to annual deposition of aeolian mineral dust.

The impact of atmospheric mineral aerosol deposition on the albedo of snow & sea ice: are snow and sea ice optical properties more important than mineral aerosol optical properties?

“…Dust layers within snowpacks are typically greater than 8 cm (e.g. Zdanowicz et al, 1998;Osada et al, 2004;Dong et al, 2013) and inspection of Fig. 10 shows that as the distance between the layers increases, the difference between the albedo of the layered snowpack and the snowpack containing a single surface layer becomes small.…”

Water-Insoluble Particles in Spring Snow at Mt. Tateyama, Japan: Characteristics of the Shape Factors and Size Distribution in Relation with Their Origin and Transportation

“…Tateyama in spring is about 6-10 m. Snow cover around the mountain area prevents wind-blown redistribution of local soil materials. As described in Osada et al (2004), snow pits at three sites were dug for snow sampling: Midagahara According to the vertical profiles of the WIP at the three sites and local dirty snow observation near the mountain, the WIP in layer 4 (MR-4, MD-4, and KR-4) were considered to be deposited at the same event on 3 January 2001. These samples of layer 4 (MR-4, MD-4, and KR-4) were analyzed to confirm the horizontal variability of dust deposition, and veracity of this image analytical method.…”

“…As described in Osada et al (2004), these layers were considered to be formed by wet deposition. In contrast, the thickness of MR-3 was very thin (2 mm) with a sharp edge of the dirty layer, suggesting that the dust particles were deposited by a dry process on the snow surface, instead of wet deposition with snowfall.…”

“…The dates of these dust events were inferred as 11 February for layer 2, 3 February for layer 3, and 3 January 2001 for layer 4, based on local dirty snow observation near Mt. Tateyama, weather conditions, and the time variation of aerosol concentrations at Murododaira (Osada et al 2004). The date of deposition for layer 1 was not specified using the matching method mentioned above.…”

“…The snow samples in this study were analyzed originally by Osada et al (2004) for dust deposition processes and weight variation of water-insoluble particles (WIP). They preliminarily reported mono-modal and bi-modal volume-size distribution of water-insoluble particles, using a laser diffraction/scattering particle size distribution analyzer.…”