THE EFFECT OF ALBEDO-REDUCING MATERIALS ON NET RADIATION AT A SNOW SURFACE

Abstract

Various albedo-reducing materials were used to increase net radiation at the surface of ripe snow. Increases were evaluated by measuring net radiation on small plots of treated and untreated snow for the period of 1 day. Nine different materials were applied at different weights per unit area for a total of 47 treatments. During short periods of variable incoming radiation, the relation between net radiation on treated and untreated snow was linear, with a positive Y intercept. Treatment effects decreased with time for carbon black materials applied at low weights. Net radiation increases averaged for the day were statistically significant in all cases and ranged from 37 to 122 percent for the various treatments. There was a tendency for the amount of treatment effect to be directly proportional to the weight per unit area of darkening material applied up to a point, above which treatment effects did not increase. Carbon black treatments were more effective than fluid coke and small particles of fluid coke were more effective than large particles. New snow tended to decrease treatment effects, but net radiation was still significantly greater on treated snow as compared to untreated snow, even with up to 4.1 cm of new snow on treated surfaces.