1. CABLE: the Australian community land surface model
Bernard Pak, Yingping Wang, Eva Kowalczyk
CSIRO Marine and Atmospheric Research
OzFlux08, Adelaide, 4-6 Feb 2008
CABLE = Community Atmosphere Biosphere Land Exchange model

2. Australian Community Climate Earth System Simulator (ACCESS) modelling program
Diagram to right shows ‘scope’
Fundamentally conceived as a modelling ‘system’ that meets a variety of needs.
Priority needs are:
Numerical weather prediction
Climate change simulation capability
Collaboration between key institutions (Bureau, CSIRO, Australian Universities,….)
CABLE will be the land-surface module of the global model ACCESS.
Who is developing Earth Systems Modelling now?
Hadley Centre (UK)
IPSL (France)
MPI (Germany)
FRCGC (Japan)
NCAR (USA)
GFDL (USA)

3. Kowalczyk et al., CMAR Research Paper 013, 2006
The general structure of CABLE
Interface to the GCM
Canopy
radiation;
sunlit & shaded
visible &
near infra-red,
albedo
SEB & fluxes;
for soil-vegetation
system:
Ef , Hf , Eg , Hg;
evapotranspiration
Carbon
fluxes;
GPP, NPP,NEP
stomata transp.
& photosynthesis
soil temp.
soil moisture
soil respiration
snow
Meteorological forcing provided by GCM are passed through the interface to CABLE (radiation, wind, pressure, CO2 concentration, air and soil temperature, precipitation, soil moisture). SEB = surface energy balance
CABLE modifies the soil temperature and moisture, calculates the carbon fluxes and passes back through interface to the GCM.
In offline mode, CABLE can work on single point or multiple points so long as the met forcing at those points are provided.
carbon pools; allocation & flow
CASA-CNP
vegetation dynamics/disturbance
Kowalczyk et al., CMAR Research Paper 013, 2006

4. Vegetation parameters required for CABLE
VEGETATION TYPE
1 broad-leaf evergreeen trees
2 broad-leaf deciduous trees
3 broad-leaf and needle-leaf trees
4 needle-leaf evergreen trees
5 needle-leaf deciduous trees
6 broad-leaf trees with ground cover /short-vegetation/C4 grass (savanna)
7 perennial grasslands
8 broad-leaf shrubs with grassland
9 broad-leaf shrubs with bare soil
10 tundra
11 bare soil and desert
agricultural/c3 grassland
13 ice
Geographically explicit data
LAI – leaf area index
fractional cover
C3/C4 - fraction
the model calculates:
z0 – roughness length
α – canopy albedo
A grouping of species that show close
similarities in their response to environmental
control have common properties such as:
- vegetation height
- root distribution
- max carboxylation rate
- leaf dimension and angle, sheltering factor,
- leaf interception capacity

5. Soil parameters required for CABLE
Soil types:
Coarse sand/Loamy sand
Medium clay loam/silty clay loam/silt loam
Fine clay
Coarse-medium sandy loam/loam
Coarse-fine sandy clay
Medium-fine silty clay
Coarse-medium-fine sandy clay loam
Organic peat
Permanent ice
Soil Properties:
- water balance:
wilting point
field capacity
saturation point
hydraulic conductivity at saturation
matric potential at saturation
- heat storage:
albedo,
specific heat, thermal conductivity
density
- soil depth
Post, W., and L. Zobler, 2000
Global Soil Types

6. Nonlinear parameter estimation
19 FLUXNET sites, including all major veg types in the temperate and subtropical climate;
Uniform parameter range ;
Optimisation was applied to each year’s measurements separately;
Each type of obs was weighted by the SD of measurements over a year.
Published in Wang et al. (Global Change Biology, 2001 and 2007)

7. A temperate evergreen forest, Tumbarumbra, Australia

8. Black line – predictions with constant Vcmax (used in most LSM): Red line – predictions with seasonal varying Vcmax as function of soil temperature at 20 cm depth. So, this is adopted as the standard calculations within CABLE for deciduous forests.

9. Relative Vcmax: deciduous forests
Leaf growth
Leaf fall
Similar trends for various deciduous forests. The relative vcmax increases during the beginning of growth season due to increase in enzymes; and then during senescence, it decreases due to degradation and translocation of leaf enzymes.
HE = Hesse, HV = Harvard Forest, VI = Vielsalm, WB = Walker Branch, WL = Park Falls/WLEF

10. Changes to-date
Major clean-up and rewriting of codes in FORTRAN90 standard, making it more modular and more flexible.
A secured website has been set up for code distribution, installation help and exchange of ideas.
Standard scripts introduced to help analyzing results.
Monthly meeting

11. Future changes
CASA-CNP: Nitrogen and phosphorus have been found to impact strongly on climate predictions. Such nutrient cycles will be implemented within the current year. It also necessitates a better phenology module.
Dynamic vegetation: a UNSW post-doc (Dr. Jiafu Mao) have just started in January. He will implement LPJ into CABLE.
Hydrology: MU and BoM have done some work, we will have at least one post-doc later this year.
Switching to IGBP vegetation types as our research show better correlation with phenological dates from satellite data.
Robert Pipunic (MU) and Adam Smith (BMRC) have applied CABLE on Kyeamba Creek and Murray Darling Basin respectively.

12. CABLE as the Australian community land surface model
Source codes and documentation are available to all registered users online at ( to register)
We are looking for collaboration to validate/improve CABLE

13. The End

14. Modelling Vcmax and Jmax

15. Parameter ranges

16. Observed and estimated vcmax per unit leaf area during growing season (mmol m-2 s-1)
Site
Estimated
observed
Harvard forest 61 56
Tumbarumbra 64 71
Hyytiala 74
Hesse 65 70