the centre for australian weather and climate research a partnership between csiro and the bureau of...
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The Centre for Australian Weather and Climate ResearchA partnership between CSIRO and the Bureau of Meteorology
ACCESS: The Australian Coupled Climate Model for IPCC AR5 and CMIP5
Daohua Bi
On behalf of the ACCESS Coupled Modelling Team
www.cawcr.gov.au
Outline1. 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 FrameworkACCESS = AusCOM + UM (hg2/3) + MOSES/CABLE
CouplerOASIS 3.2.5
AtmosphereUM 7.3
Sea IceCICE 4.1
Land SurfaceMOSES/CABLE
OceanMOM4p1
Atmospheric model UM
(HadGEM2/3 configuration)
Resolution: 192 x 145 1.875 lon x 1.25 lat 38 levels in the vertical
Ocean Biogeochemistry(to be implemented) AusCOM
‘core’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
UM
CICE
MOM
a2i
i2a
i2o
o2i
cpl cpl
cpl cpl cpl
• 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
The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology
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 (AusCOM = MOM4p1 + CICE4.1)
Working version for AR5(experiments done!)
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.
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 Coupled Model PD/PI Simulations: Assessment everlasting debugging/tuning/reconfiguring…
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):
The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology
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.a4xCO2 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 bestarted
Global Average SAT in the Historical Runsagainst 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
The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology
SST
Thick 1.3Thin 1.0
PIhPI1p4C
T_gbl_ocn (‘normalised’)
PIhPI1p4C
SST change in the hPI runs and obs
1976~2005 – 1870~1899
1.0 1.3
Obs
Temperature change in the ocean interior
ACCESS1.3 ACCESS1.0
Meridional Overturning Circulation (MOC) & NADWF (Max AMOC)
Sv
(106 m
3 s-1)
AMOCGMOC
1.3 NADWF1.0 NADWF
PIhPI1p4C
CSIRO. A. Sullivan et. al. Climate Change Beijing 2011
Barotropic Streamfunction /ACC Transport
Sv
(106 m
3 s-1)
PIhPI1p4C
ACC Transport
ENSO Power Spectra (ACCESS and Mk3.6)
ACCESS1.0 hPI σ=0.69
HadISSTACCESS1.0
UKHG2UKHG3
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
ENSO Seasonality: hPI (1950~2005) PI (0301-0400)
ACCESS1.0
ACCESS1.3
Mk3.6
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)
The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology
PI NHhPI NH
PI SHhPI SH
ACCESS 1.0 ACCESS 1.3
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 ResearchA partnership between CSIRO and the Bureau of Meteorology
Dr Daohua (Dave) BiSenior Research Scientist
Phone: (+61-3-) 92394507Email: [email protected]: www.cawcr.gov.au
Thank youwww.cawcr.gov.au
IPCC AR5 Timelines
2010 2011 20132012
Data after this point will probably not be included in AR5-cited publications
CMIP5 continues to accept model results well after IPCC AR5, at least through 2013
Analysis papers for IPCC must be submitted by 31 July 2012
IPCC WG1 final plenary
2014
Model output starts becoming available to users via the ESG
CSIRO. Sullivan et. al. Climate Change Beijing 2011
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
The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology