Radiative forcing by dust and black carbon on the Juneau Icefield, Alaska

In May and July 2016, we collected snow samples from the Juneau Icefield, where glacier melt rates are among the highest on Earth. Analyses of black carbon, a by‐product of biomass and fossil fuel burning, and dust, small mineral particles that are deposited on the ice field, indicate that these particles darken the surface enough to be a significant factor in the ice field’s melt. Because white snow reflects solar radiation whereas dark particles absorb it, these particles enhance melting of the snow beyond that which is caused simply by warming temperatures. As the length of time between spring and autumn snowfalls expands and light‐absorbing particles accumulate at the surface throughout the summer months, the particles are likely to become increasingly important players in the ice field’s energy balance. The role of these and other light‐absorbing particles should be further investigated and incorporated into melt models.


Nagorski, S., Kaspari, S., Hood, E., Fellman, J. and McKenzie Skiles, S.. 2019. Radiative forcing by dust and black carbon on the Juneau Icefield, Alaska. Journal of Geophysical Research: Atmospheres. 1247: 3943-3959. https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JD029411. DOI: https://doi.org/10.1029/2018JD029411.