Predator-prey models and jet stream variability with applications to climate modeling
The dynamics of the large scale atmosphere is characterised by highly organised, quasi-2D turbulence. The jet stream is an emerging phenomenon which is the key determinant of the large scale flow away from the tropics. Since the mid 20th century we have attempted to understand the interactions between this jet stream and the rest of the atmospheric turbulence.
In this presentation I will introduce a heuristic low order description of this interaction, which turns out to have the structure of a predator-prey model. A key property is that, contrary to previous descriptions, the model's basic state is characterised by finite amplitude turbulence. The model shows some counterintuitive responses to external forcing. In the presentation I will show how the model, and its responses are verified in real world data and GCMs. Some speculative outcomes for the response of the climate to increased GHGs are discussed.