Quantifying Relative Contributions of Light‐Absorbing Particles From Domestic and Foreign Sources on Snow Melt at Sapporo, Japan During the 2011–2012 Winter

Abstract

Light-absorbing particles (LAPs), such as black carbon (BC) and mineral dust (hereafter referred to as dust), within the snow cover modulate the snow-atmosphere energy exchanges by reducing the snow albedo. This modulation is particularly important at visible wavelengths . When the absorption of shortwave radiant flux at the snow surface is enhanced by the reduction in the visible snow albedo and surface air temperature is sufficiently high, surface snow melting can be induced. The presence of meltwater accelerates snow grain growth via wet snow metamorphism (Brun, 1989), resulting in the reduction of the near-infrared snow albedo . This implies that the presence of LAPs in snow cover plays a unique role in positive feedback that induces snow ablation and increase in surface air temperature, that is, the snow-albedo feedback (e.g., Budyko, 1969;Qu & Hall, 2007). The first detailed quantification of the impacts of LAPs within snow and ice on the terrestrial climate system was carried out by Hansen and Nazarenko (2004).During the past two decades, efforts to consider the effects of LAPs on snow albedo explicitly in snow models have been made to provide more reliable quantitative estimates. Flanner and Zender (2005) developed the snow, ice, and aerosol radiative (SNICAR) model, which calculates radiative transfer in the

Spatiotemporal Variations in Summertime Arctic Aerosol Optical Depth Caused by Synoptic‐Scale Atmospheric Circulation in Three Reanalyses

“…That is consistent with the composited fields reported by Gray et al (2021) and Vessey et al (2022). These results indicate the relatively large influence of aerosol variability associated with PC-2 on Arctic climate systems, including sea ice and snow (Niwano et al, 2021).…”

Black carbon dominated dust in recent radiative forcing on Rocky Mountain snowpacks

“…Pristine seasonal snow is highly reflective [4][5][6] but even small amounts of light absorbing particles (LAP) deposited on snow darken the surface, thereby lowering albedo and increasing absorbed solar energy [7][8][9][10]. This positive radiative forcing at the snow surface drives earlier and faster snowmelt [9,[11][12][13] particularly as LAP concentrate on the snowpack surface in spring [14], thereby reducing water storage and advancing the timing of streamflow [15]. Enhanced snowmelt results in earlier snow disappearance, contributing to atmospheric warming because of the 'snow albedo feedback' [6,7,10,16,17] while extending periods of summer forest growth and late-summer drought.…”

Snow albedo and its sensitivity to changes in deposited light-absorbing particles estimated from ambient temperature and snow depth observations at a high-altitude site in the Himalaya

“…This dependence is included to some extent in Equation 9, where it is shown that the absorption efficiency by LAP is scaled with the grain size. In a more detailed model framework (e.g., Niwano et al, 2021), where the LAP has a more realistic vertical distribution in the snowpack, the estimated top layer and its LAP concentration will be less than what is assumed here. Likewise, such a framework would also have a different d, and is likely to be greater than 4 mm to fully encompass the optically active surface snow layers.…”

“…In recent years, different sophisticated modeling tools have been developed in order to account for many of the complex interactions between LAPs and snow (e.g., Jacobi et al, 2015;Tuzet et al, 2017;Skiles and Painter, 2019;Tuzet et al, 2020;Niwano et al, 2021). These models are very complex and commonly require extensive data sets to force the models (including detailed meteorological data) and to validate the results (including frequent temporal snow pit observations).…”