Date: 2024-03-15 16:00-17:30 zoom link

Speaker: Alef Sterk（Rijksuniversiteit Groningen）

Title: Bifurcations in the Lorenz-96 model

Abstract: The Lorenz-96 model is widely used as a test model for various geophysical applications, such as data assimilation methods and predictability studies. The model consists of a system of $n$ differential equations which satisfy a circulant symmetry condition. In addition, the model depends on a scalar forcing parameter $F$ which can act as a bifurcation parameter. A question of mathematical interest is to what extent the bifurcation scenarios depend on the dimension $n$ of the model. The aim of this talk is to discuss the circulant symmetry of the model and its effect on the possible bifurcation scenarios. The primary focus will be on the occurrence of finite cascades of pitchfork bifurcations, where the length of such a cascade depends on the divisibility properties of the dimension $n$. A particularly intriguing aspect of this phenomenon is that the parameter values $F$ of the pitchfork bifurcations seem to satisfy the Feigenbaum scaling law.