ACCESS: The Australian Coupled Climate
Model for IPCC AR5 and CMIP5
www.cawcr.gov.au
Daohua Bi
On behalf of the ACCESS Coupled Modelling Team
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
Outline
1. Introduction to the ACCESS coupled model
• Framework: sub-models and coupling approach
• Versions: core configurations
2. Results from the ACCESS AR5/CMIP5 experiments:
•
•
•
•
Pre-industrial control (PI)
Historical forcing
(hPI)
1% CO2 increase
(1p)
Abrupt 4xCO2
(4C)
Model results: “Traditional validation”:
Global average SAT/SST
ENSO behavior
Ocean circulation
Sea ice performance
3. Summary and ongoing work
Introduction to the
ACCESS Coupled Model
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
ACCESS:
The Australian Community Climate and Earth System Simulator
• ACCESS has been developed by the Centre for Australian Weather
and Climate Research (CAWCR), a partnership between CSIRO and
the Bureau of Meteorology, with Australian universities, under the
Australian Climate Change Science Program (ASSCP, funded and
administered by the Department of Climate Change and Energy
Efficiency) . It will deliver new generation national capability in
numerical weather prediction, seasonal forecasting, ocean climate
modelling, coupled earth system climate and climate change
simulations.
• ACCESS coupled model is built by coupling the UK Met Office
atmospheric model UM (Unified Model), and other sub-models as
required, to the Australian Climate Ocean Model (AusCOM), an IPCC
class coupled ocean-sea ice model consisting of the GFDL MOM4p1
ocean model and the LANL CICE4.1 sea ice model, under the PRISM
OASIS3.2-5 coupling framework. Primary goal of this model is to run
the IPCC AR5 and CMIP5 experiments.
ACCESS Coupled Model Framework
ACCESS = AusCOM + UM (hg2/3) + MOSES/CABLE
Atmospheric model UM
Atmosphere
UM 7.3
(HadGEM2/3 configuration)
Resolution: 192 x 145
1.875 lon x 1.25 lat
38 levels in the vertical
Land Surface
MOSES/CABLE
Coupler
OASIS 3.2.5
Ocean
Biogeochemistry
(to be implemented)
Ocean
MOM4p1
Sea Ice
CICE 4.1
AusCOM1.0 release Users Guide (Bi, D. and S. Marsland, 2010):
http://www.cawcr.gov.au/publications/technicalreports/CTR_027.pdf
ACCESS/AusCOM Ocean-Sea Ice Tri-polar Grid
Horizontal:
•Global tripolar with resolution of
360 x 300;
Longitudinal: uniform 1°;
Latitudinal: equatorial meridional
refinement: 1/3° for10°S-10°N;
Mercator grid in Southern Ocean:
1° at 30°S to 1/4° at 78°S.
The ocean and sea ice components
share this horizontal grid.
Vertical:
•50-level ocean covering 0~6000m with
a resolution ranging from 10m for
0~200m column to 250m for the
abyssal ocean.
ACCESS Coupling Strategy
cpl
a2i
i2a
UM
cpl
i2o
cpl cpl
cpl
o2i
CICE
MOM
• Different coupling frequencies for
atm  ice (3 hours), and
ice  ocean (every time step, e.g., 1 hr)
• CICE functions as a ‘coupling media’ between UM and MOM
• 62 coupling fields (2D): a2i 24, i2o 13, o2i 7, i2a 18
ACCESS CM: short history and multiple versions
Assembled successfully in mid 2009, fully functioning since early 2010, and has
since then been going through extensive debugging, tuning and re-configuring
processes, eventually “evolved” into 4 versions:
Version
Components
Notes
ACCESS1.0
AusCOM + hg2 + MOSES
Working version for AR5
(experiments done!)
(AusCOM = MOM4p1 + CICE4.1)
ACCESS1.1
AusCOM + hg2 + CABLE
Work needed
ACCESS1.2
AusCOM + hg3 + MOSES
Abandoned
ACCESS1.3
AusCOM + hg3 + CABLE
Working version for AR5
(most wanted)
Candidates for AR5/CMIP5: ACCESS1.0 and ACCESS1.3.
This talk presents partial results of AR5 experiments (outlined above) by both
ACCESS1.0 and ACCESS1.3, comparing ACCESS with observation and other
models when appropriate/applicable.
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
ACCESS Coupled Model PD/PI Simulations:
Assessment  everlasting debugging/tuning/reconfiguring…
Tens of century scale PD climate simulations (control experiments) have been
performed in the past two years, mainly with hg3-M (v1.2) and hg3-C (v1.3),
and recently with hg2-M (v1.0).
Assessments have been continuously conducted to validate the model,
generally focusing on the following criteria:
• Size of global average SAT or SST regional bias and global drift.
• Overall skill in simulating a set of key climatic fields, globally and over
Australia.
• Realism of simulation of the mean state in the tropical Indo/Pacific Ocean
region.
• Realism of simulation of ENSO and influence on Australian rainfall.
• Realism of polar region sea ice extent.
• Realism of world ocean circulations, especially SO, including strength of the
Antarctic Circumpolar Current and extent of late winter deep convection.
• Extent of any other substantial biases evident.
• ……
Q: Is ACCESS (and which version) suitable for AR5/CMIP5?
ACCESS CM Development Progress: ‘Warming up’
~20 mths ago
T.P.Cooling
> 3 °C
Now
T.P. Cooling
< 1 °C
ACCESS CM
AR5/CMIP Experiments
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
Status of ACCESS AR5/CMIP5 Simulations
ACCESS AR5/CMIP5 experiments with the frozen versions 1.0 (hg2-M) & 1.3 (hg3-C):
Exp.
Length (yrs)
V1.0
V1.3
Note
PI Control (PI)
500
ongoing
ongoing
Historical (hPI)
156 (1850~2005) done
done
data
RCP8.5
95 (2006~2100)
done
nearly done
to be
RCP4.5
95 (2006~2100)
done
nearly done
published
1%p.a4xCO2
140
done
nearly done
officially
Abrupt 4xCO2
150
done
nearly done
soon!
AMIP Runs
30(1979~2008)
done
done
……
Other prescribed
SST forcing (x 2)
30
to be
started
to be
started
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
Global Average SAT in the Historical Runs
against observation and other models
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
Global SAT: ACCESS1.0 vs ACCESS1.3
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
Global SST/T_gbl_ocn: ACCESS 1.0 vs 1.3
T_gbl_ocn (‘normalised’)
SST
PI
hPI
1p
4C
PI
hPI
1p
4C
Thick 1.3
Thin 1.0
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
SST change in the hPI runs and obs
1.0
1.3
Obs
1976~2005 – 1870~1899
Temperature change in the ocean interior
ACCESS1.0
ACCESS1.3
Meridional Overturning Circulation (MOC) &
NADWF (Max AMOC)
Sv (106m3s-1)
GMOC
AMOC
PI
hPI
1p
4C
1.0 NADWF
1.3 NADWF
Barotropic Streamfunction /ACC Transport
PI
hPI
1p
4C
Sv (106m3s-1)
ACC Transport
CSIRO. A. Sullivan et. al. Climate Change Beijing 2011
ENSO Power Spectra (ACCESS and Mk3.6)
ACCESS1.0 hPI σ=0.69
ACCESS1.0 PI σ=0.72
ACCESS1.3 hPI σ=0.66
ACCESS1.3 PI σ=0.69
CSIRO Mk3.6 hPI σ=0.79
CSIRO Mk3.6 PI σ=0.72
HadISST
ACCESS1.0
UKHG2
UKHG3
ENSO Seasonality:
hPI (1950~2005)
ACCESS1.0
ACCESS1.3
Mk3.6
PI (0301-0400)
Sea Ice Distribution/Seasonal Variance
CSIRO. IUGG 2011, Melbourne
Time series of annual mean sea ice area in
the PI and hPI runs (units: 10^6 km^2)
ACCESS 1.0
ACCESS 1.3
PI NH
hPI NH
PI SH
hPI SH
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
Summary and Ongoing Work
• ACCESS coupled model has 4 functional versions differing from one another only in the
atmosphere-land component configuration.
• Each of the versions has their own advantages and disadvantages, with the hg2-M version
(V1.0) being the overall, arguably, “best” (in terms of the general performance in simulating
the world climate, especially the PI-PD contrast of the surface thermal states), but hg3-C
(V1.3) the “favourite” because of its new and special features in configuration.
• Two working versions of ACCESS CM (1.0 and 1.3) have been used to perform the IPCC
AR5/CMIP5 experiments, with most of the simulations already completed and the results are
comparable to the other models. Data of the ACCESS experiments are to be available soon
to “public”.
• Further tuning and reconfiguring work has been underway to improve ACCESS1.3 for
possible “additional”/new simulations to be delivered to CMIP5 after AR5 phase.
• Continue development based on ACCESS1.3 towards the next generation of ACCESS CM
(v?.?) for AR6/CMIP6 (if any).
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology
Dr Daohua (Dave) Bi
Senior Research Scientist
Phone: (+61-3-) 92394507
Email: Dave.Bi@csiro.au
Web: www.cawcr.gov.au
Thank you
www.cawcr.gov.au
IPCC AR5 Timelines
Analysis papers
for IPCC must be
submitted by
31 July 2012
2010
Model output
starts becoming
available to users
via the ESG
2011
2012
Data after this point
will probably not be
included in AR5-cited
publications
IPCC WG1
final plenary
2013
2014
CMIP5 continues to
accept model results
well after IPCC AR5, at
least through 2013
HadGEM2-AO:
• HadGEM2-AO (N96, L38, O(1))
• Physics changes relative to HadGEM1:
• Convection – inclusion of adaptive detrainment parameterization,
depth criteria for shallow convection removed
• Boundary Layer – non gradient stress parameterization
• Land Surface – snowmelt over frozen ground runs off rather than
infiltrates
• Ocean – viscosity reduced, diffusion lowered in upper layers
• River runoff – enhanced ocean diffusion where river outflow
• Aerosols – improved representation of sulphate and biomass
aerosols. Inclusion of mineral dust and secondary organic aerosols
CSIRO. Sullivan et. al. Climate Change Beijing 2011
HadGEM3-AO:
• HadGEM3-AO (major changes from HadGEM2-AO)
• N96, L38
• PC2 cloud scheme
• Convection scheme developments including removal of level sensitivities,
corrections to convective cloud calculations, reduced CMT
• BL scheme developments (8C BL, more BL levels, new solver)
• Improved soil treatment
• Better treatment of coastal regions
• NEMO Orca(1), L42
• CICE
• OASIS coupling
• Also exploring other resolutions
• Horizontal : Atmosphere N216; Ocean 0.25
• Vertical: Atmosphere L63, L85; Ocean L50, L90
CSIRO. Sullivan et. al. Climate Change Beijing 2011
Monsoon Analysis: Monsoon Working Group
• Basic error
• can be seen at a range of time and spatial resolutions.
• It is established very quickly, within the first ~10 days of run.
• Many characteristics of monsoon have been studied
•
•
•
•
•
•
•
•
Onset
Vertical structure
Source of air
Inter-annual variability and teleconnections with SST
Intra-seasonal variations
Modification of PV in cross-equatorial flow
Diurnal cycle
Strong v weak monsoon years
• Many sensitivity studies carried out
• Many things have a small influence (vertical resolution, PC2, maritime
continent,…)
• Strongest impact from changes to convective closure
CSIRO. Sullivan et. al. Climate Change Beijing 2011
Convective closure
• Two possible convective closures in UM
• Buoyancy based or CAPE based (decrease CAPE over given timescale)
• For RH-based CAPE stability issues mean;
• Reduced CAPE timescale when column RH exceeds a threshold
• Increased updraft mass flux to stabilise convection
• Effective timescale is much lower than ‘physical’ timescale
• Replace RH-based CAPE with W-based CAPE
• Threshold now based on vertical velocity instead of RH
• Increased physical and effective CAPE timescale (1hour -> 2 Hours)
• Results in
• Reduced convective intensity across whole ITCZ and small but widespread
increases in tropical specific humidity
• Suppression of Indian Ocean convection linked to reduced anomalous
descent over India and local RH increase
• Positive feedback on convection over India
CSIRO. Sullivan et. al. Climate Change Beijing 2011
The Centre for Australian Weather and Climate Research
A partnership between CSIRO and the Bureau of Meteorology