Ventilation and Radon Dynamics in Maine Seasonal Snowcover

Radon concentrations and fluxes were measured for seasonal snowpack on Baldpate Mtn. in Newry, Maine during the winter of 2004. A solar radiation and temperature logging system was developed to monitor the snowpack during the radon measurements. Radon ground flux measurements were performed using a RAD-7 alpha spectrometer and ranged from 0.49 to 0.64 pCi m s for two different locations. Radon concentration as a function of time was measured inside the snowpack using a Honeywell A9000 radon monitor and showed average radon concentrations ranging from 1 to 12 pCi L, though maximum concentrations of over 80 pCi L were observed. Wind-driven and natural circulation airflows within the snowpack were shown to be the major factors controlling radon dynamics. Dilution rates of 1.25 pCi L h were correlated with windspeeds of 9 m s, while radon concentration rates of 0.8 pCi L h were observed during periods of calm. Comparison of long term track-etch cup measurements with radon diffusion theory showed that radon within the snowpack rarely exists in steady state distribution due to the ventilation effects of wind and natural circulation air flows. This study shows that radon dynamics can be used to measure air flows inside the snowpack.