Statistical state dynamics of jet/wave coexistence in barotropic beta-plane turbulence

Abstract

Jets coexist with planetary scale waves in the turbulence of planetary atmospheres. The coherent component of these structures arises from cooperative interaction between the coherent structures and the incoherent small-scale turbulence in which they are embedded. It follows that theoretical understanding of the dynamics of jets and planetary scale waves requires adopting the perspective of statistical state dynamics (SSD) which comprises the dynamics of the interaction between coherent and incoherent components in the turbulent state. In this work the S3T implementation of SSD for barotropic beta-plane turbulence is used to develop a theory for the jet/wave coexistence regime by separating the coherent motions consisting of the zonal jets together with a selection of large-scale waves from the smaller scale motions which constitute the incoherent component. It is found that mean flow/turbulence interaction gives rise to jets that coexist with large-scale coherent waves in a synergistic manner. Large-scale waves that would only exist as damped modes in the laminar jet are found to be transformed into exponentially growing waves by interaction with the incoherent small scale turbulence which results in a change in the mode structure allowing the mode to tap the energy of the mean jet. This mechanism of destabilization differs fundamentally and serves to augment the more familiar S3T instabilities in which jets and waves arise from homogeneous turbulence with energy source exclusively from the incoherent eddy field and provides further insight into the cooperative dynamics of the jet/waves coexistence regime in planetary turbulence.

22 pages, 15 figures

References in corpus (6)

• Direct Statistical Simulation of Out-of-Equilibrium Jets
• The Generalized Quasilinear Approximation: Application to Zonal Jets
• The long-term steady motion of Saturn's Hexagon and the stability of its enclosed jet-stream under seasonal changes
• A minimal model of self-sustaining turbulence
• Cumulant expansions for atmospheric flows
• S3T stability of the homogeneous state of barotropic beta-plane turbulence

Cited by in corpus (20)

• The Generalized Quasilinear Approximation: Application to Zonal Jets
• A statistical state dynamics-based study of the structure and mechanism of large-scale motions in plane Poiseuille flow
• Turbulence statistics in a 2D vortex condensate
• Recent Developments in Theories of Inhomogeneous and Anisotropic Turbulence
• Three-Dimensional Rotating Couette Flow Via The Generalised Quasilinear Approximation
• Dynamics of Zonal Flows: Failure of Wave-Kinetic Theory, and New Geometrical Optics Approximations
• On the Rayleigh--Kuo criterion for the tertiary instability of zonal flows
• Instability of the roll/streak structure induced by free-stream turbulence in pre-transitional Couette flow
• Magnetic suppression of zonal flows on a beta plane
• Large-scale-vortex dynamos in planar rotating convection
• Wave kinetics of drift-wave turbulence and zonal flows beyond the ray approximation
• Exploiting self-organized criticality in strongly stratified turbulence
• Synchronization of Low Reynolds Number Plane Couette Turbulence
• Structure formation in turbulence as instability of effective quantum plasma
• Vertically Sheared Horizontal Flow-Forming Instability in Stratified Turbulence: Analytical Linear Stability Analysis of Statistical State Dynamics Equilibria
• Statistical state dynamics of weak jets in barotropic beta-plane turbulence
• Coarse-graining two-dimensional turbulence via dynamical optimization
• Numerical simulation of the geometrical-optics reduction of CE2 and comparisons to quasilinear dynamics
• Non-equivalence of quasilinear dynamical systems and their statistical closures
• Direct Statistical Simulation Using Generalised Cumulant Expansions