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o Land Surface Scheme in CRCM5
o Advanced modules
o Summary
Outline
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Overview: Land surface scheme in CRCM
• Thermally separate vegetation canopy, snow cover and three soil layers (0.1, 0.25, 3.75m).
• Four main vegetation structural types identified (needleleaf trees, broadleaf trees, crops and grass)
• Up to four subareas allowed for land surface type: vegetation covered, bare soil, snow with vegetation and snow over bare soil
• One soil type for each grid cell
Canadian LAnd Surface Scheme; Verseghy, 1991; Verseghy et al., 1993
Verseghy, 2000
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Enhanced features
Option for deeper soil configuration
Ability to model organic soils
Optional mosaic formulation
Ability to model lateral movement of soil water
Enhanced snow density and snow interception
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Recent interest in permafrost Permafrost degradation can have adverse impacts
on socio-economic and eco-environmental systems
Climate model projections indicate a rise in the global average temperatures over the next century (IPCC, 2007)
http://www.amap.no/acia/Highlights.pdf
Drunken forest in Siberia
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Permafrost (offline) Modelling
Drawback:Cannot capture the land/atmosphere feedbacks
Can a climate model with a shallow LSS be used to model ALT and near surface permafrost?
0 – 6 m
1961-1990
Simulated average ALT for current and future climates
0 – 9 m
2041-2070
Sushama et al. (2006)
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Can a climate model with a shallow LSS be used to model ALT and near surface permafrost?
Infinite half space 3m thick slab with zero flux boundary condition
Smerdon and Stieglitz (2006; GRL)
Lawrence et al. (2008)
Nicolsky et al. (2007)
Alexeev et al. (2007)
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CRCM experiment with shallow and deep Soil Layers3 layers
0.10 m0.35 m
4.10 m
0.10 m0.25 m
3.75 m
10.0 m
16.0 m
24.0 m
37.0 m
59.0 m
95.0 m
6.0 m 4.0 m 6.0 m
8.0 m
13.0 m
22.0 m
36.0 m
2.5 m
13 layers(all 13 layers)
Bedrock: 0.10 m – 3.60 m
Max. depth to bedrock
4.10 m
95.0 m
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Soil Initial conditions
• Stevens et al. (2008)forward modelled the ECHO-g simulated, millenial, paleoclimatic histories to obtain the sub-surface thermal profiles, which were validated over North-America, against available borehole measurements
• The above forward modelling was done for the period 1000-1990 and the profiles from 1961 were used as initial conditions for the experiments with the deeper version of CLASS3.4
CRCM experiment with shallow and deep Soil Layers
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JJA
197
9-20
02D
JF 1
978-
2001
°C
Seasonal means, 3 layer run – 13 layer run
°C
°C
°C
W/m²
W/m²
1st layer soil temperature Sensible Heat Flux 2 meter temperature
different scales!
Source: Katja Winger
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Organic soil
Distribution of organic soil
Organic soil has higher porosity and hydraulic conductivity compared to mineral soils
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3-layer: No organic soil
3-layer: with organic soil
Simulated annual-mean temperature for the top soil layer
Source: Yanjun Jiao
Region with organic soilInclusion of the organic soil parameterization leads to much cooler temperatures
Organic soil
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Other Modules in CRCM5(multitude of surface types)
• Lakes- Hostetler and Flake models being implemented
The Lake Model Intercomparison Project (LakeMIP): http://www.unige.ch/climate/lakemip/index.html
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Dynamic vegetation
Canadian Terrestrial Ecosystem Model (Arora,
2003)
• Photosynthesis• Autotrophic respiration• Heterotrophic respiration• Phenology• Turn over of live veg, • Mortality• Allocation • Disturbance due to fire,• Land use related carbon emissions
Other Modules in CRCM5
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River-Lake system model
Routing models:WATRouteVariable velocity (Arora and Boer, 1999; Lucas-Picher, 2003)Variable lag (Sushama et al., 2004)
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Summary
• CLASS: LSS in the Canadian RCM• Features required for high-latitude regions• Upcoming modules• Opportunities to test/share/use modules
• Yet to come …. Thermokarst, glaciers, icesheets, ……