Status: this preprint was under review for the journal TC but the revision was not accepted.
The measurement and impact of light absorbing particles on snow surfaces
Carl G. Schmitt,Bria L. Riggs,Ulyana N. Horodyskyj,Alia L. Khan,Holly A. Ewing,John D. All,and Wilmer Sanchez Rodriguez
Abstract. Light absorbing particles (LAPs) can have a significant impact on the albedo of snow. LAPs absorb solar radiation which warms surrounding snow thereby increasing melt or sublimation rates. Historically, LAP concentrations have been reported in terms of a mass mixing ratio, typically in nanograms of black carbon per gram of snow. While this representation is convenient for sampling, it can lead to deceptive results if there is significant surface accumulation of LAPs due to snow loss or dry deposition. Here we demonstrate that LAPs concentrated on the snow surface can substantially affect the albedo and typical sampling strategies and reporting protocols can lead to highly erroneous estimates of albedo.
Theoretical calculations and measurements both show that the reduction in albedo by LAPs can be twice as strong when particles are concentrated on the surface as opposed to being mixed within the top thin layer of snow. Current commonly used sampling strategies are not sufficient to determine the necessary information to assess the impact of surface LAPs on snowpack albedo.
To facilitate more accurate albedo estimates, we propose a new sampling strategy to better characterize LAP distribution in and on snowpacks. Theoretical calculations and experimental measurements show that snowpack albedo can be much better characterized when using the suggested sampling strategy to determine the distribution of LAPs present.
How to cite. Schmitt, C. G., Riggs, B. L., Horodyskyj, U. N., Khan, A. L., Ewing, H. A., All, J. D., and Sanchez Rodriguez, W.: The measurement and impact of light absorbing particles on snow surfaces, The Cryosphere Discuss. [preprint], https://doi.org/10.5194/tc-2019-162, 2019.
Received: 05 Jul 2019 – Discussion started: 15 Aug 2019
Dirty snow melts faster than clean snow because the dark particles absorb light from the sun. Common techniques for measurements and analysis assume that the dirt particles are mixed in with the snow. Many processes lead to the dirt particles forming a layer on the surface of the snow rather than being mixed in. This publication demonstrates the importance of considering a surface layer and provides a new sampling protocol to enable the measurement of the surface layer.
Dirty snow melts faster than clean snow because the dark particles absorb light from the sun. ...