• Coupled earth system models
• The powers of ACCESS
• Research links
• Infrastructure
• Expertise

Scientists at The Centre for Australian Weather and Climate Research, a partnership between CSIRO and the Bureau of Meteorology, are developing Australia’s next generation climate model: the Australian Community Climate and Earth System Simulator (ACCESS).

ACCESS is a fully coupled earth system model being developed with several Australian universities on the nation’s most powerful supercomputers operated by the National Computational Infrastructure and the Bureau of Meteorology.

It embodies a national approach to climate and weather prediction modelling that will give CSIRO and the Bureau of Meteorology the best possible scientific tools for climate impact and adaptation analysis, and weather forecasting.

ACCESS will also help Australian scientists contribute to major international climate modelling and prediction projects, and will provide Australia’s major input to the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC) on the world’s climate future.

Coupled earth system models

Coupled earth system models seamlessly link together models of the oceans, atmosphere, sea-ice, land surface, global carbon cycle and chemistry, and aerosols, to simulate changes in the Earth’s climate systems with ever-increasing precision.

These models enable scientists not only to project major changes in the Earth’s climate in the longer term, but to make short and medium-range weather forecasts and seasonal predictions for particular regions.

Skill and reliability on one time scale engenders confidence for other time scales (such as climate change), and vice versa.

ACCESS represents a huge advance over earlier, simpler climate models, and is tested and fed by data from earth-observing satellites and other climate sensors.

The powers of ACCESS

Australians increasingly want to know what climate change will mean for them locally and expect continued improvements in predictive capabilities. This includes:

• storm surge frequencies for coastal communities, insurance companies and emergency services
• effective cropping and livestock regime planning for primary producers
• health concerns such as the southern migration of mosquito-borne diseases
• the frequency of intense heat periods, such as those in early 2009.

On completion, ACCESS will also provide improved forecasts of air quality, and of severe weather features such as tropical cyclones. It will provide improved forecasts in areas of increasing community and industry interest such as renewable energy, and assist in diagnosing, analysing and forecasting climate-sensitive natural resource systems.

An important milestone in the ACCESS development was reached in September 2009 when the numerical weather prediction component was implemented operationally by the Bureau. ACCESS will begin producing detailed climate projections for the globe and Australian region by 2011–12.

Research links

The development of ACCESS involves significant involvement from Australian universities and international agencies.

Strong links are maintained with agencies in:

• the United Kingdom (UK MetOffice)
• the United States (National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory, Los Alamos National Laboratory)
• France
• Korea
• New Zealand
• South Africa
• Norway
• China.

Australian universities assist with development and testing of CSIRO’s Atmosphere – Biosphere Land Exchange Model (CABLE) to ensure Australian vegetation is well represented in ACCESS, as well as the Australian Community Ocean Model (AusCOM) to capture major features of Southern Hemisphere ocean circulation.

Earth system modelling expertise is provided to the CSIRO themes of Climate and Atmosphere and National Security and to the Wealth from Oceans Flagship.

Infrastructure

Climate and Earth system models such as ACCESS require not just computational power, but significant computing and IT infrastructure and software engineering skills.

The development, maintenance and effective use of such models therefore critically depends on advanced IT infrastructure, especially:

• high performance supercomputing
• large volume data storage and high speed connectivity
• source code and visualisation infrastructure.

Expertise

Atmospheric modelling: development of the central atmospheric model, including the dynamical-core, physical parameterisations, and model numerics in general. Development of ensemble systems.

Ocean and coupled modelling: large-scale ocean and sea ice modelling, methodology for coupling to the atmosphere, ocean-atmosphere exchange processes.

Land surface and carbon cycle modelling: terrestrial and ocean biogeochemical cycles, land use and land cover change, global change biology, land-atmospheric exchange, atmospheric inversion and model-data fusion.

Data assimilation: objective analysis (variational and ensemble) of randomly distributed data, quality control, and inversion of remotely sensed data, all based on Bayesian techniques.

Chemistry and aerosols: atmospheric modelling at all scales, including atmospheric chemistry and aerosols, surface and boundary-layer processes, atmospheric emissions, dispersion and deposition, and environmental and air pollution modelling.

Model evaluation: model evaluation, especially in numerical weather prediction, features such as ENSO, IOD, SAM, MJO that influence Australian climate, radiation and cloud parameterisations, and the use of satellite data to evaluate model performance.

Model systems: climate modelling, including code optimisation, parameterisation development, and model analysis.

Complex systems science: development of integrated assessment models, coupling economic, social and earth system models for evaluation of global and national development. Boundary layer turbulence: flow and transport in complex terrain with application to measurement and modelling of land-atmosphere exchange.

Read more about CSIRO Marine and Atmospheric Research.