Hierarchical Tree Model for Barotropic Turbulence Interaction with Zonal Jets

Abstract:

Large coherent structures arising from self organization of turbulence are observed in many geophysical settings such as zonal jets in the Earth's oceans and atmosphere. It is critical to account for inhomogeneities and anisotropy in order to study such phenomena. The hierarchical tree model (Aurell 1994) is a class of dynamical systems that describe inhomogeneous turbulence as locally interacting elements in both wave number and real space using a discrete set of shell variables. The model efficiently calculates the evolution of disparate scales in the system ranging from mesoscale turbulence to large scale coherent structures. We extend the model to incorporate anisotropy and account for the interaction of turbulence with the emergent coherent structures that evolve self-consistently. We then apply the tree model to study the cascade of barotropic turbulence interacting with zonal jets on the beta plane.