CABLE: the Australian community land surface model

Bernard Pak, Yingping Wang, Eva Kowalczyk

CSIRO Marine and Atmospheric Research

OzFlux08, Adelaide, 4-6 Feb 2008

Australian Community Climate Earth System

Simulator (ACCESS) modelling program

ACCESS

ESM

GraphicsVisualisation

Super-computing

DataAssimilation

ModelEvaluation

SoftwareEngineering

Down-scaling

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,….)

Interface to the GCM

Canopy radiation;sunlit & shaded visible &near infra-red,albedo stomata transp.

& photosynthesis

Carbon fluxes;GPP, NPP,NEP

SEB & fluxes;for soil-vegetationsystem:Ef , Hf , Eg , Hg;

evapotranspiration

soil moisture snow

carbon pools; allocation & flow

The general structure of CABLE

CASA-CNP

vegetation dynamics/disturbance

soil temp. soil respiration

Kowalczyk et al., CMAR Research Paper 013, 2006

Vegetation parameters required for CABLE

Geographically explicit data

LAI – leaf area index

fractional cover C3/C4 - fraction the model calculates: z0 – roughness length

α – canopy albedo

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 soil10 tundra11 bare soil and desert12 agricultural/c3 grassland13 ice

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

Soil parameters required for CABLESoil 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, 2000Global Soil Types

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)

A temperate evergreen forest, Tumbarumbra, Australia

0 5 10 15 20 25La

tent

hea

t (F

e)

-40

0

40

80

120

0 5 10 15 20 25

Sen

sibl

e he

at (F

h)

-100

0

100

200

Month

0 5 10 15 20 25

NE

E (F

c)

-5

-4

-3

-2

-1

0

Observed Fe (W m-2)-20 0 20 40 60 80 100120140

Mod

elle

d F

e (

W m

-2)

-200

20406080

100120140

Observed Fh (W m-2)

-40 -20 0 20 40 60 80 100120

Mod

elle

d F

h (

W m

-2)

-40-20

020406080

100120

Observed NEE (mol m-2 s-1)-5 -4 -3 -2 -1 0

Mod

elle

d N

EE

-5

-4

-3

-2

-1

0

Deciduous forest, Walker Branch

0 10 20 30 40

Late

nt h

eat

(W

/m2 )

-40

0

40

80

120

Fh

0 10 20 30 40

Sen

sibl

e he

at

(

W/m

2 )

-100

0

100

200

Fnee

Month0 10 20 30 40

N

EE

(

mol

m-2

s-1

)

-8

-4

0

4

Relative Vcmax: deciduous forests

Deciduous forests

Month0 2 4 6 8 10 12

0.00.20.40.60.81.01.2

HE (48N)HV(42N)VI (50N)WB(36N)WL (46N)Leaf

growth Leaf fall

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

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.

CABLE as the Australian community land surface model

• Source codes and documentation are available to all registered users online at https://teams.csiro.au/sites/cable/default.aspx (email bernard.pak@csiro.au to register)

• We are looking for collaboration to validate/improve CABLE

The End

Modelling Vcmax and Jmax

wpfc

wps

c

leafT

osd

nn

ss

nsTdcc

f

v

j

Tff

T

TTf

kLk

DDC

AafGGffvV

1997) Leuning C, 25(at

species) C3for 1997 (Leuning

effects) age (leaf

canopy) of leaf from up (scaling

;

o2

)(

1

/))exp(1(

)/1)((

max

max

2

5.0,

00maxmax

Parameter ranges

Table 2. Initial values and ranges of optimized model parameters

Parameter Unit Initial value Range

xL _____ 1.0 0.8 – 1.0

xjmax _____ 1.0 0.1-5.0

jmax/vcmax _____ 2.0 Weight=100

xrs _____ 1.0 0.01-50

Topt oC 20 0-50

T oC 20 0-100

Observed and estimated vcmax per unit leaf area during growing

season (mol m-2 s-1)

Site Estimated observed

Harvard forest 61 56

Tumbarumbra 64 71

Hyytiala 74 64

Hesse 65 70