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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, ……