Avalanches, Breathers and Flow Reversal in a Continuous Lorenz-96 Model

TL;DR

This paper derives a continuous Lorenz-96 model that conserves energy but is non-Hamiltonian, revealing avalanche-like breather solutions that cause flow reversals through wave-mean flow interactions, akin to sand pile avalanches.

Contribution

It introduces a continuous, energy-conserving Lorenz-96 model with a novel avalanche mechanism causing flow reversal, expanding understanding of wave-mean flow interactions.

Findings

Avalanche-like breather solutions induce flow reversals.

External forcing triggers outburst-recharge dynamics.

Model captures wave-mean flow interaction phenomena.

Abstract

For the discrete model suggested by Lorenz in 1996 a one-dimensional long wave approximation with nonlinear excitation and diffusion is derived. The model is energy conserving but non-Hamiltonian. In a low order truncation weak external forcing of the zonal mean flow induces avalanche-like breather solutions which cause reversal of the mean flow by a wave-mean flow interaction. The mechanism is an outburst-recharge process similar to avalanches in a sand pile model.