A Multi-Scale Intercepted Snow Sublimation Model
Date
2000-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Degree Level
Masters
Abstract
Physically-based equations describing snow sublimation were used to provide a snow-covered forest boundary condition for a one-dimensional land surface scheme. The mass and energy balance equations were up-scaled from the snow grain scale to that of a canopy control volume using a fractal scaling technique. Modification of the land surface scheme's calculation of turbulent transfer and within-canopy ambient humidity were required to accommodate this nested control volume approach.
Tests in late winter in a southern boreal forest mature jack pine stand against measured sublimation showed that the multi-scale model provides good approximations of sublimation losses during half-hourly periods and periods of 3 to 4 days. Sublimation averaged 0.5 kg m-2 daily, with minimum and maximum daily losses of 0.16 and 0.72 kg m-2 . Cumulative differences between estimates and measurements of canopy temperature, humidity, and intercepted snow load over 7 days of simulation were 0.7 K, 7.5 Pa, and 0.103 kg m-2, respectively.
At a nearby regenerating jack pine site, measured peak latent heat flux density ranged from -14.6 W m-2 to -40.9 W m-2. Testing of the model at this site yielded reasonable estimates of latent and sensible heat fluxes during an overnight period, but did not estimate latent heat flux as well during periods involving larger snow loads and incoming solar radiation, possibly due to errors introduced by neglect of sub-canopy snow energetics. Further work to improve heat storage terms, and the inclusion of subcanopy snow energetics would improve the multi-scale model performance.
Description
Keywords
Citation
Degree
Master of Science (M.Sc.)
Department
Agricultural and Bioresource Engineering
Program
Hydrology