Enhancement of snow albedo reduction and radiative forcing due to coated black carbon in snow

Abstract

Abstract. When black carbon (BC) is mixed internally with other atmospheric particles, the BC light absorption effect is enhanced. This study explicitly resolved the optical properties of coated BC in snow based on the core / shell Mie theory and the Snow, Ice, and Aerosol Radiative (SNICAR) model. Our results indicated that the BC coating effect enhances the reduction in snow albedo by a factor ranging from 1.1–1.8 for a nonabsorbing shell and 1.1–1.3 for an absorbing shell, depending on the BC concentration, snow grain radius, and core / shell ratio. We developed parameterizations of the BC coating effect for application to climate models, which provides a convenient way to accurately estimate the climate impact of BC in snow. Finally, based on a comprehensive set of in situ measurements across the Northern Hemisphere, we determined that the contribution of the BC coating effect to snow light absorption exceeds that of dust over northern China. Notably, high enhancements of snow albedo reduction due to the BC coating effect were found in the Arctic and Tibetan Plateau, suggesting a greater contribution of BC to the retreat of Arctic sea ice and Tibetan glaciers.

Fluorescence characteristics, absorption properties, and radiative effects of water-soluble organic carbon in seasonal snow across northeastern China

“…To establish the radiative effect impact of snowpack WSOC in northeastern China, we used SAMDS to simulate spectral snow albedo. This model is based on asymptotic radiative transfer theory, which has been verified by previous studies (Li et al, 2021b;Wang et al, 2017) consistent with previous studies (Pu et al, 2021). With the solar zenith angle fixed at 60°, in line with our sampling dates and locations, we calculated the reduction in spectral snow albedo for the UV-vis (280-400 nm) and ultraviolet-near infrared (UV-NIR; 280-1500 nm) bands.…”

The sensitivity and evolutionary trajectory of the mountain cryosphere: Implications for mountain geomorphic systems and hazards

“…Changes in glacier or snowpack albedo can also take place as a result of the presence of black carbon on the surface, which refers to atmospheric carbonaceous particles formed by biomass burning. Black carbon and other light‐absorbing impurities on snow or ice can decrease albedo and increase shortwave radiation absorption (Bertoncini et al, 2022; Pu et al, 2021). A radiative forcing model suggests that black carbon can decrease albedo by 12.8% in fresh snow and 23.3% on old snow (Zhang et al, 2021).…”

Modelling light-absorbing particle–snow–radiation interactions and impacts on snow albedo: fundamentals, recent advances and future directions

“…To facilitate model improvements, a number of BC-snow albedo parameterisations that account for different aspects of the aforementioned key factors have been recently developed (e.g. Dang et al 2015Dang et al , 2016He et al 2017aHe et al , 2018aSaito et al 2019;Pu et al 2021;Shi et al 2022a), to which we refer readers who are interested.…”

“…LAP-snow mixing state, LAP coating and particle structure and snow microstructure) in altering snow albedo and radiative effects (e.g. Picard et al 2009;Flanner et al 2012;Liou et al 2014;Dang et al 2016;He et al 2017aHe et al , 2019Dumont et al 2021;Pu et al 2021;Shi et al 2022a), which have not been systematically summarised. Therefore, this study seeks to synthesise recent advances, challenges and future directions in modelling LAP-snow-radiation interactions from microscopic (particle level) to macroscopic (bulk snow optical properties and albedo) perspectives, which makes it a unique review.…”