NCI's partnership with the Bureau of Meteorology continues to lead to improvements to Australia's national weather prediction models. Visualisations of the data output from the recently enhanced development version of the capital city forecast model make it easy for collaborating scientists to understand and share the improvements made in this latest version.

The Bureau's Dr Charmaine Franklin has been working with NCI's VizLab team to produce these high-resolution visualisations. The visual representation of the model's outputs shows all of the details present in the model in an easy-to-understand way. The carefully crafted visual imagery highlights the increases in accuracy of the improved model over Darwin and the Top End and helps to identify areas for future model development efforts.

Dr Franklin says, "We use NCI for all of the Bureau's numerical model development work. It's absolutely crucial to our ability to keep improving our models over time.

The visualisations that NCI has produced based on this modelling have been invaluable in showcasing the new developments to our collaborators around the world."

Improved guidance from the Bureau's Numerical Weather Prediction (NWP) systems feeds directly into the Bureau forecast process, and is thus a key element in delivering improved forecasts to the public. In the next 12 months significant upgrades are scheduled for the capital city forecast models, including the introduction of sophisticated "Data Assimilation" methods to define the state of the atmosphere at the start of the forecast. For the atmospheric model itself, there are both improvements generally, and an increased emphasis on the fidelity of the simulation of tropical weather, which will lead to significant improvement in NWP guidance, especially for the Darwin and Brisbane NWP systems.

Dr Franklin is helping to improve the representation of clouds and thunderstorms in the upgraded 1.5 km model by using model outputs from sub-km resolution simulations. While the 1.5 km simulations are able to accurately model many aspects of cloud formation, some atmospheric processes benefit from even finer resolutions to be modelled appropriately. Analysing the sub-km model output produces a greater understanding of the initiation and development of thunderstorms, knowledge that feeds into improvements in the 1.5km model. This helps to make the modelling of rapidly changing weather and small-scale cloud formations much more accurate than in the past.

Getting the model to represent the impacts of fine-scale processes is an important part of these improvements, because small variations in weather patterns can lead to major impacts on a large-scale. Accurately modelling those small differences improves the quality of weather forecasts, especially when it involves rapidly changing weather like squalls and sudden rainfall in the tropics.

In addition to the immediate and direct impact on Bureau NWP systems, Dr Franklin's work also contributes to the advancement of high-resolution atmospheric modelling more broadly, through its contribution to the international partnership that coordinates development of the "Unified Model" across Australia, the United Kingdom, India, New Zealand, Korea and South Africa.

NCI and the Bureau of Meteorology have been working together on weather model development for around 10 years. As one of the original members of the NCI Collaboration, the Bureau has a long history of scientific work on NCI's Raijin supercomputer, with a particular shared interest in the optimisation of model codes for massively parallel systems. In 2016, development work between BoM and NCI led to a 40% increase in the ACCESS model's performance on thousands of computer processors at once.