A Dynamical Systems Characterisation of Atmospheric Jet Regimes

Abstract

Abstract. Atmospheric jet streams are typically separated into primarily eddy-driven, or polar-front jets and primarily thermally-driven, or "subtropical" jets. Some regions also display merged jets, resulting from the (quasi) co-location of the regions of eddy generation with the subtropical jet. The different locations and driving mechanisms of these jets issue from very different underlying mechanisms, and result in very different jet characteristics. Here, we link our understanding of the dynamical jet maintenance mechanisms, mostly issuing from conceptual or idealised models, to the phenomena observed in reanalysis data. We specifically focus on developing a unitary analysis framework, grounded in dynamical systems theory, which may be applied to both idealised model and reanalysis data, and allow for direct intercomparison. Our results provide a proof-of-concept for using dynamical systems indicators to diagnose jet regimes in a versatile, conceptually intuitive and computationally efficient fashion.

Do Atlantic‐European Weather Regimes Physically Exist?

“…These metrics are related to the intrinsic predictability of the atmosphere and therefore to the stability (here in the context of atmospheric variability) of the flow: a highly persistent (low θ), low-dimensional (low d) state will be more stable than a low-persistence (high θ), high-dimensional (high d) one (Messori et al, 2017). This approach has been applied to various atmospheric fields (e.g., Faranda et al, 2019a;Messori et al, 2021). Indeed, it has been shown that d and θ can offer a dynamical characterization of synoptic systems over several geographical regions (Faranda, Alvarez-Castro, et al, 2017;Hochman et al, 2019;Hochman, Alpert, et al, 2020).…”