Reflection of Solar Light from Surface Snow Loaded with Light-Absorbing Impurities: A Case Study of Black Carbon, Mineral Dust, and Ash

Abstract

Using a hemispherical directional reflectance factor instrument, spectral data of dirty snow containing black carbon (BC), mineral dust (MD), and ash was collected from multiple locations to investigate the impact of these lightabsorbing impurities (LAIs) on snow reflectance characteristics. The findings revealed that the perturbation of snow reflectance caused by LAIs is characterized by nonlinear deceleration, indicating that the reduction in snow reflectance per unit ppm of LAIs declines as snow contamination increases. The reduction in snow reflectance caused by BC may reach saturation at elevated particle concentrations (thousands of ppm) on snow. Snowpacks loaded with MD or ash initially exhibit a significant reduction in spectral slope around 600 and 700 nm. The deposition of numerous MD or ash particles can increase snow reflectance beyond the wavelength of 1400 nm, with an increase of 0.1 for MD and 0.2 for ash. BC can darken the entire measurement range (350−2500 nm), while MD and ash can only affect up to 1200 nm (350−1200 nm). This study enhances our understanding of the multi-angle reflection characteristics of various dirty snow, which can guide future snow albedo simulations and improve the accuracy of LAIs' remote sensing retrieval algorithms.

Winter Dust Storms Impact the Physical and Biogeochemical Functioning of a Large High Arctic Lake

“…8−10 However, dust can also contain contaminants and act as a light-absorbing impurity (LAI) when deposited on high albedo surfaces such as snowpacks, glaciers, and ice. 11,12 As eolian processes increase in frequency due to human-induced climate and land use changes, 2 these LAI properties have become a concern in cryospheric regions of the world due to their radiative forcing impact. 13 High Arctic regions are subjected to the deposition of aerosols originating from distant locales, with up to 50% of the aerosols, including biogenic organic ones, coming from Eurasian countries.…”

“…The composition of atmospheric dust depends primarily upon the surface sediments/crusts and geological substrates from which it is eroded and sourced. , These erosional processes produce mineral dust aerosols ranging in size from a few nanometers to hundreds of micrometers, with an inverse relationship between particle size and atmospheric residence time. ,, During transport through the atmosphere, these dust aerosols can, for example, scatter and absorb short- and long-wave radiation, act as cloud condensation nuclei and ice nucleating particles, and react with other atmospheric aerosols. 2 Upon deposition, mineral dust can enhance productivity through fertilization within distant receiving ecosystems. − However, dust can also contain contaminants and act as a light-absorbing impurity (LAI) when deposited on high albedo surfaces such as snowpacks, glaciers, and ice. , As eolian processes increase in frequency due to human-induced climate and land use changes, these LAI properties have become a concern in cryospheric regions of the world due to their radiative forcing impact …”