Hurricanes are just one of the many complex components of our planet's climate.Partnering with the Met Office
Modelling the physics of our climate
At the heart of every weather forecasting system is a dynamical core which solves the equations describing the fluid dynamics and thermodynamics that lead to our weather. The solutions are extremely complex and their accuracy governs the quality of the forecast they produce – so it’s vital they’re as good as they can be.
It takes about 10 years to develop a new dynamical core; the Met Office has been working on its latest incarnation under the project title ENDGAME (Even Newer Dynamics for General Atmospheric Modelling of the Environment). It’s moving towards the final stages now and during that formative process, experts at the University of Exeter have contributed their specialist expertise across some key areas.
Prof John Thuburn, from the University’s College of Engineering, Mathematics and Physical Sciences, said: “The dynamical core is the computer code that solves the equations needed to make a forecast. Even with computers as big and fast as we have today, there is still a limit to how much detail we can resolve in a model – otherwise the calculations would take too long. The dynamical core must represent those resolved scales accurately and efficiently.”
Forecasts start with current observations of the atmosphere. Then the model – using the equations from the dynamical core, coupled with models of unresolved processes – will predict what will happen in 15 minutes time, then step forward another 15 minutes, and so on until you have a 5 or 10 day forecast. If the dynamical core isn’t right, then at every step the forecast will get less and less accurate.
My work on this project included reviewing all the details of the formulation for the core – which is basically 200 pages of mathematical equations, and giving feedback to the Met Office team. I also looked at wave propagation, one of my areas of expertise. This means making sure the core accurately captures the propagation of different kinds of atmospheric waves. I also looked at the question of conservation properties of dynamical cores, looking at mass, momentum, energy and other factors, and which ones are most important to the accuracy of the solution.
It’s great that we are able to offer our expertise here to contribute to the creation of what will be a state of the art dynamical model. It’s enormously satisfying to think that future weather forecasts will be based in part on our work.
Professor John Thuburn
