The modelling program has now settled in with weekly MOM/COSIMA meetings while working with other research programs on projects that will continue to improve our models and the way we use them in our research. This work has extended to stakeholders with Christian Jakob co-authoring Next-generation climate models: a step change for net-zero and climate adaption(pdf) as part of a series in the Royal Society Brief series for policymakers, Climate change: science and solutions, aimed at the Glasgow COP meeting. Christian has also been appointed as a member of the Science Review Group for the Met Office Hadley Centre Climate Programme. You can find out more about the group here.
Meanwhile, Andy Hogg hosted ANU’s World Oceans Day event, which attracted 130 attendees and was broadcast live on YouTube.
At the same time, our work continues despite COVID, with researchers from the Modelling program were included as part of an international team that performed a systematic evaluation of global fire–vegetation model simulations across nine FireMIP models in order to quantify their ability to reproduce a range of fire and vegetation benchmarks. While some FireMIP models were better at representing certain aspects of the fire regime, no model clearly outperformed all other models across the full range of variables assessed. Benchmarking scores indicated that seven out of nine FireMIP models were able to represent the spatial pattern in burnt area. The models also reproduced the seasonality in burnt area reasonably well but struggled to simulate fire season length and were largely unable to represent interannual variations in burnt area. The results will allow researchers to weigh the different models based on the score for the variable of interest, giving more weight to models which perform better for these variables.
We also worked with three other CLEX research programs to use Sydney, Australia’s largest city, as a test case for our new configuration of the Weather and Research Forecasting model run at a very high resolution of 800m with a new urban classification scheme that describes the complexity of Sydney’s built environment. The level of detail we saw from these high-resolution simulations allowed the researchers to interrogate the role of local breezes to either enhance or dissipate heat. This capability is the first step towards building an understanding of how our cities will need to adapt to climate change. You can see the full video and transcript of the animation resulting from this research, here.
Often, we use real-world observations to confirm how well our models reproduce weather and climate phenomena. A remarkable experiment of this type was the Colorado State University Convective CLoud Outflows and UpDrafts Experiment (C3LOUD-Ex). Its aim was to enhance our understanding of deep convective storm processes and how they are represented in numerical models. To achieve this end they flew drones and radiosondes into storms while also making ground observations. This allowed the researchers to obtain detailed measurements of the area of cold pools, how long they lasted, and updraft velocities. The processes responsible for the cold pool observations were then explored by the researchers and were found to support recent results from high-resolution numerical models.
As well as the land and atmosphere, we have also completed some impressive work on ocean models. Navid Constantinou and Andy Hogg have brought into question a long-standing paradigm, which holds that the ocean-atmospheric interactions drive long-term variability in the oceans. These include the highly influential climate modes of the El Nino Southern Oscillation and the Pacific Decadal Oscillation. Their work, which used eddy-resolving models, found that even without atmospheric interaction, the ocean by itself produced long-term variability that echoed these modes. The implication of this work is that ocean eddies alone, which are often not resolved in many models, have the potential to trigger long-term modes of variability that have a powerful impact on the climate of Australia and the rest of the world.
Our researchers also work on codes and packages that can help visualise the outputs of models, opening the way to come up with new solutions and areas of research. Navid Constantinou and collaborators recently developed GeophysicalFlows.jl, a Julia package that provides solvers for geophysical fluid dynamics problems in periodic domains. Currently, the package includes solvers for two-dimensional turbulence, barotropic or equivalent barotropic quasi-geostrophic flows, surface quasi-geostrophic flows, and multi-layer quasi-geostrophic flows. All modules are well documented and include continuous integration of both simple unit tests and physics-specific tests for each module. The examples in the package’s documentation demonstrate how one can easily set up, customise, solve, and produce animations for the model of their choice. Some tutorials even demonstrate how one can code up a solver for a partial differential equation of their liking. This package gives scientists, the ability to visualise solutions of particular models with ease while, at the same time, also being able to change parameter values and rerun the simulation.
As well as examining next-generation models, we are also bringing through the next generation of climate scientists. Zebedee Nicholls recently submitted his PhD, On the state of reduced complexity climate modelling, while we also got to welcome new PhD Student Ashley Barnes who will work with Andy Hogg on developing and applying the latest generation of Australian coupled Ocean-Atmosphere models to processes in the Southern Ocean and/or Antarctica.