Measurements of snow mass flux and transport rate at different particle diameters in drifting snow

Abstract

Wind tunnel experiments were carried out to investigate the snow mass flux and the snow transport rate as functions of friction velocity and particle diameter. Friction velocities obtained with an ultra sonic anemometer was from u *=0.15 to 0.39 m/s. The number flux and the particle size of drifting snow were measured with a new snow particle counter at heights of 16 to 61 mm above the snow surface. The horizontal snow mass flux at each particle diameter d, q d, decreased exponentially with height q d∝exp(− λ d z/( u * 2/ g)), where z is the height, g is the acceleration due to gravity and λ d is a dimensionless parameter. The constant λ d was independent of friction velocity, and at larger particle diameters, approached to 0.3. The total snow transport rate increased with the power (3.96) of friction velocity, but the total snow transport rate at each particle diameter showed that the power decreased with increasing particle diameter, and approached to 3.