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United States Department of Agriculture

Agricultural Research Service

Title: Distributed Simulation of Snowcover Mass-and Energy-Balance in the Boreal Forest

Authors
item Marks, Daniel
item Link, Timothy - OREGON STATE UNIVERSITY

Submitted to: Hydrological Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 1999
Publication Date: N/A

Interpretive Summary: The accurate distributed simulation of snowpack deposition and ablation beneath forest canopies is complicated by the fact that vegetation canopies strongly affect the snow surface energy balance. The canopy alters the radiation balance of the snowcover and reduces the wind speed at the snow surface. Simple canopy adjustment algorithms for solar and thermal radiation, and wind speed are used in conjunction with commonly available land cover classifications to spatially distribute sub-canopy solar and thermal radiation, air and soil temperature, humidity, wind speed, and precipitation. The distributed climate surfaces are used to drive a 2-layer coupled energy-and mass-balance snowmelt model over 2 areas within the BOREAS study region for the 1994-1995 snow season. Model results are validated using both automatic and manually collected snow depth data. The simulated timing and rate of snowpack development and ablation at both study areas is well represented beneath the canopy types where validation data is present. Rigorous evaluation of model performance beneath the full range of canopy types requires information regarding the spatial distribution of snow covered area during the ablation period. This study demonstrates that given basic landcover parameters, relatively simple canopy adjustments coupled with an energy balance model can be used to estimate climate conditions and snowcover processes within a range of boreal forest covers.

Technical Abstract: The accurate distributed simulation of snowpack deposition and ablation beneath forest canopies is complicated by the fact that vegetation canopies strongly affect the snow surface energy balance. The canopy alters the radiation balance of the snowcover and reduces the wind speed at the snow surface. Simple canopy adjustment algorithms for solar and thermal radiation, and wind speed are used in conjunction with commonly available land cover classifications to spatially distribute sub-canopy solar and thermal radiation, air and soil temperature, humidity, wind speed, and precipitation. The distributed climate surfaces are used to drive a 2-layer coupled energy-and mass-balance snowmelt model over 2 areas within the BOREAS study region for the 1994-1995 snow season. Model results are validated using both automatic and manually collected snow depth data. The simulated timing and rate of snowpack development and ablation at both study areas is well represented beneath the canopy types where validation data is present. Rigorous evaluation of model performance beneath the full range of canopy types requires information regarding the spatial distribution of snow covered area during the ablation period. This study demonstrates that given basic landcover parameters, relatively simple canopy adjustments coupled with an energy balance model can be used to estimate climate conditions and snowcover processes within a range of boreal forest covers.

Last Modified: 10/19/2014
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