HR: 0830h
AN: C41B-0953    [PDF]
TI: Evaluation of snow process over short vegetation in land surface modeling
AU: * Lee, Y L
EM: ylee@coas.oregonstate.edu
AF: College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Admin Building, Corvallis, OR 97331-5503 United States
AU: Mahrt, L
EM: mahrt@coas.oregonstate.edu
AF: College of Oceanic and Atmospheric Sciences, Oregon State University, 104 Ocean Admin Building, Corvallis, OR 97331-5503 United States
AB: Sublimation and snow melt process over short canopies are examined with a two- layer canopy model. The model's performance is evaluated with observation from the North Park Basin, Colorado, taken during the Cold Land Surface Processe s Experiment. The site is covered with a sage community with an average height of 30cm. Two cases with weak winds are selected for further examination. In the first case, the snow covers the ground surface but there is no intercepte d snow in the canopy. In the second case, the canopy is partially covered with intercepted snow. Improved representation of snow interception, subcanopy parameterization and the change of relative canopy height due to changing snow depth are implemented in the land surface model. The modified model better simulates both sublimation and sensible heat flux from the canopy and ground surface by giving more realistic energy partition between the ground and the canopy. It is shown that the modelled latent heat flux is sensitive to the intercepted snow amount because less intercepted snow leads to greater absorption of solar energy by the canopy, more buoyancy generation of turbulence above the canopy and possible stratification of the subcanopy. Hence, it is necessary to establish an appropriate treatment for intercepted snow amount in the model. {\bf Key words}: sublimation, short canopy, subcanopy snow
DE: 1863 Snow and ice (1827)
DE: 1878 Water/energy interactions
DE: 3307 Boundary layer processes
DE: 3322 Land/atmosphere interactions
DE: 3379 Turbulence
SC: Cryosphere [C]
MN: 2003 Fall Meeting