1. The Centre for Australian Weather and Climate Research A 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

2. 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

3. Introduction to the ACCESS Coupled Model The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

4. 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.

5. ACCESS Coupled Model Framework ACCESS = AusCOM + UM (hg2/3) + MOSES/CABLE Coupler OASIS 3.2.5 Atmosphere UM 7.3 Sea Ice CICE 4.1 Land Surface MOSES/ CABLE Ocean MOM4p1  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

6. 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.

7. ACCESS Coupling Strategy UM CICE MOM a2i i2a i2o o2i 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

8. 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: VersionComponentsNotes ACCESS1.0AusCOM + hg2 + MOSES (AusCOM = MOM4p1 + CICE4.1) Working version for AR5 (experiments done!) ACCESS1.1AusCOM + hg2 + CABLEWork needed ACCESS1.2AusCOM + hg3 + MOSESAbandoned ACCESS1.3AusCOM + hg3 + CABLEWorking 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.

9. 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…

10. ACCESS CM Development Progress: ‘Warming up’ ~20 mths ago T.P.Cooling > 3 °C Now T.P. Cooling < 1 °C

11. ACCESS CM AR5/CMIP Experiments The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

12. 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)V1.0V1.3Note PI Control (PI)500ongoing Historical (hPI)156 (1850~2005)done data RCP8.595 (2006~2100)donenearly doneto be RCP4.595 (2006~2100)donenearly donepublished 1%p.a  4xCO2140donenearly doneofficially Abrupt 4xCO2150donenearly donesoon! AMIP Runs30(1979~2008)done …… Other prescribed SST forcing (x 2) 30to be started to be started

13. 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

14. Global SAT: ACCESS1.0 vs ACCESS1.3 The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

15. 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 1.3 Thin 1.0 PI hPI 1p 4C T_gbl_ocn (‘normalised’) PI hPI 1p 4C

16. SST change in the hPI runs and obs 1976~2005 – 1870~1899 1.0 1.3 Obs

17. Temperature change in the ocean interior ACCESS1.3 ACCESS1.0

18. Meridional Overturning Circulation (MOC) & NADWF (Max AMOC) Sv (10 6 m 3 s -1 ) AMOC GMOC 1.3 NADWF1.0 NADWF PI hPI 1p 4C

19. CSIRO. A. Sullivan et. al. Climate Change Beijing 2011 Barotropic Streamfunction /ACC Transport Sv (10 6 m 3 s -1 ) PI hPI 1p 4C ACC Transport

20. ENSO Power Spectra (ACCESS and Mk3.6) ACCESS1.0 hPI σ=0.69 HadISST ACCESS1.0 UKHG2 UKHG3 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

21. ENSO Seasonality: hPI (1950~2005) PI (0301-0400) ACCESS1.0 ACCESS1.3 Mk3.6

22. Sea Ice Distribution/Seasonal Variance CSIRO. IUGG 2011, Melbourne

23. 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 NH hPI NH PI SH hPI SH ACCESS 1.0 ACCESS 1.3

24. 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

25. 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

26. IPCC AR5 Timelines 20102011 2013 2012 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

27. 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

28. 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

29. 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

30. 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

31. The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology