ACASA - Confex...By 26% Shorter snow season for top heavy biomass structure ACASA Introduction...
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ACASA Simulation of Surface Energy Fluxes & Snow Interception Using a Higher Order Closure Multi-Layer Soil-Vegetation-Atmospheric Model
Transcript of ACASA - Confex...By 26% Shorter snow season for top heavy biomass structure ACASA Introduction...
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ACASA
Simulation of Surface Energy Fluxes & Snow Interception Using a Higher Order Closure Multi-Layer
Soil-Vegetation-Atmospheric Model
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Snow cover is a critical driver of energy and water budget yet lack accurate modeling
1. State Of Sierra Forests Report Web
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Laura [email protected]
ACASA Introduction Methods Results Conclusion
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Vertical structure & its variation complicate snow processes and modeling
• However few studies explicitly model complex processes in multiple vertical layers!
ACASA Introduction Methods Results Conclusion
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Laura [email protected]
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Most studies of forest structure impact on snow processes only look at planar variables
ACASA Introduction Methods Results Conclusion
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Objective:Simulate differing forest canopy structures’
impact on energy & snow budgets
in Sierra Nevada, CAusing a multilayer soil-canopy-atmosphere model
ACASA Introduction Methods Results Conclusion
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Laura [email protected]
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Temperature, humidity, shortwave radiation, CO2, wind speed, pressure
10 layerswithin-canopy
4 soil layers
10 layersabove-canopy
Image modified from Eric Kent © 2015
9 sunlit leaf angles1 shaded leaf angle
Energy budget, temperature, physiology, radiative transfer
equations and water budget
Snow
ACASA Introduction Methods Results Conclusion
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Below canopy snowpack
Snow processes in ACASA Precipitation
ThroughfallInterception
Melt
Drip
Evaporation/sublimation
Evaporation/sublimation
ACASA Introduction Methods Results Conclusion
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Soil
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Simulated grassland & 3 tree canopy types
Canopy parametersGrassland Cedar
Umbrellapine
Fir
• 1-sided total plant area indices
• Canopy architecture
• Leaf/canopy drag coefficient
• Canopy height
• Near infrared reflectivity
• Visible leaf reflectivity
ACASA Introduction Methods Results Conclusion
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ACASA Introduction Methods Results Conclusion
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Laura [email protected]
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Average late winter below canopy snowpack depth
(m)
Grass 1.84
Fir 0.53
Larch 0.42
Umbrella Pine 0.37
Evaporation <By 26%
Shorter snow season for top heavy biomass structure
ACASA Introduction Methods Results Conclusion
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Fir Larch Umbrella Pine
Difference in onset of beneath canopy snowpack melt from grassland control (days)
Evaporation <By 31%
12 16 18
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0.02.04.06.08.0
10.012.014.016.018.020.0
-25.00 -20.00 -15.00 -10.00 -5.00 0.00 5.00 10.00
Height above ground (m)
Latent heat flux (W m-2)
EvaporationCondensation
Counter-gradient fluxes occur frequently
ACASA Introduction Methods Results Conclusion
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Laura [email protected]
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Conclusion
ACASA Introduction Methods Results Conclusion
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Acknowledgements
ACASA
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References
ACASA
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