The Modular Arbitrary-Order Ocean-Atmosphere Model: MAOOAM v1.0

TL;DR

This paper introduces MAOOAM v1.0, a flexible reduced-order ocean-atmosphere model that enables analysis of spectral truncation effects on climate variability, balancing resolution and computational tractability.

Contribution

The paper presents a modular, arbitrary-order coupled ocean-atmosphere model allowing easy physics modifications and spectral resolution analysis.

Findings

Identification of spurious behaviors at low resolution

Assessment of low-frequency variability robustness

Proposal of an optimal configuration balancing resolution and complexity

Abstract

This paper describes a reduced-order quasi-geostrophic coupled ocean-atmosphere model that allows for an arbitrary number of atmospheric and oceanic modes to be retained in the spectral decomposition. The modularity of this new model allows one to easily modify the model physics. Using this new model, coined the "Modular Arbitrary-Order Ocean-Atmosphere Model" (MAOOAM), we analyse the dependence of the model dynamics on the truncation level of the spectral expansion, and unveil spurious behaviour that may exist at low resolution by a comparison with the higher-resolution configurations. In particular, we assess the robustness of the coupled low-frequency variability when the number of modes is increased. An "optimal" configuration is proposed for which the ocean resolution is sufficiently high, while the total number of modes is small enough to allow for a tractable and extensive analysis of the dynamics.