Structure of the project
The A2C2 project is divided into three workpackages (WPs).
WP1 Mathematical and Statistical Issues
The notion of attractor (or strange attractor) is generally easy to picture for autonomous dynamical systems, i.e. without time-varying forcings. The properties of the strange attractor provide information on conditions of predictability and the general shape of the system trajectories. This autonomous property is obviously not met for the real climate system, due to time varying forcings from solar variations, volcanic eruptions and man made changes in atmospheric composition. A rudimentary way of reconciling this conundrum is to consider that the climate system is “locally” in equilibrium (e.g., for 30 years) with the slowly varying forcings, and assuming that intervals of 30 years are close to “infinity” in order to trajectories to sample the whole attractor. One can then describe the evolution of the climate attractor over sliding intervals of 30 years.
WP 2 Toolkit development
We envisage the development of a computer platform to compute flow analogues from various databases and allowing for parameter testing. The idea is to create a generic tool that will be used for the specific climate-related questions we want to explore. This toolkit will be disseminated to the scientific community with an open source license. The goal is to facilitate the use of flow analogue methods in climate research. Hence it will allow the re-definition of geographical regions so that users can apply it in their own research.
WP 3 Applications
The applications of the flow analogue method are numerous. We will focus on two scientific challenges, for which such methodology provides innovative information. The two applications make an intensive use of the flow analogue methodology in order to infer probability distributions of atmospheric patterns, and assess the statistical significance of changes in distributions.