Water Resources Research Act Program

Details for Project ID 2019CO036B

The Dynamic Nature of Snow Surface Roughness

Institute: Colorado
Year Established: 2019 Start Date: 2019-03-01 End Date: 2020-02-29
Total Federal Funds: $5,000 Total Non-Federal Funds: $2,600

Principal Investigators: Steven Fassnacht

Abstract: Aerodynamic roughness length, z0, when applied to a snow-covered surface, is typically considered as a static parameter within energy equations, which are then incorporated in hydrological and atmospheric models. However, observations of z0 have shown that it should be dynamic and need to be modeled as such. The snow surface has been found to change spatially and temporally based on the underlying topography, vegetation, and meteorological factors. Three study areas have been chosen to monitor the variations of z0. Each site includes anemometers and easy accessibility to measure using LIDAR during periods of snow accumulation and melt. The objectives of this work are to i) calculate z0 based on anemometric data and surface geometry measured with LIDAR; ii) calculate z0 based on variations with scale and resolution; iii) determine the relation between z0, snow depth, and snow-covered area; and iv) apply these dynamic z0 values to hydrologic models. The findings of this research will assist in creating a more accurate insight to predicting snowpack water yield, land surface and atmospheric energy models, and the application of incorporating a dynamic z0 roughness at a variety of scales.