Statistics of the General Circulation from Cumulant Expansions

TL;DR

This paper extends cumulant expansion methods to a two-layer atmospheric model, showing that the statistically steady state predicted aligns well with direct numerical simulations, thus validating the approach for large-scale atmospheric flow analysis.

Contribution

It introduces an extended cumulant expansion framework for a two-layer baroclinic model, demonstrating its effectiveness in capturing steady-state statistics.

Findings

Cumulant expansion accurately predicts steady-state statistics.

Good agreement between cumulant expansion results and numerical simulations.

Supports the use of cumulant methods for large-scale atmospheric flow analysis.

Abstract

Large-scale atmospheric flows may not be so nonlinear as to preclude their statistical description by systematic expansions in cumulants. I extend previous work by examining a two-layer baroclinic model of the general circulation. The fixed point of the cumulant expansion describes the statistically steady state of the out-of-equilibrium model. Equal-time statistics so obtained agree well with those accumulated by direct numerical simulation.