the centre for australian weather and climate research a partnership between csiro and the bureau of...

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


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


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.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


Global SAT: ACCESS1.0 vs ACCESS1.3


Global SST/T_gbl_ocn: ACCESS 1.0 vs 1.3


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)


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 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


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


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


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

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