Submitted as: model description paper
29 Mar 2022
Submitted as: model description paper | 29 Mar 2022
Status: this preprint is currently under review for the journal GMD.

CANOPS-GRB v1.0: a new Earth system model for simulating the evolution of ocean-atmosphere chemistry over geologic timescales

Kazumi Ozaki1,2, Devon B. Cole3, Christopher T. Reinhard2,3,4, and Eiichi Tajika5 Kazumi Ozaki et al.
  • 1Department of Environmental Science, Toho University, Funabashi, Chiba 274-8510, Japan
  • 2NASA Nexus for Exoplanet System Science (NExSS)
  • 3School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
  • 4NASA Interdisciplinary Consortia for Astrobiology Research (ICAR), Alternative Earths Team, Riverside, CA, USA
  • 5Department of Earth and Planetary Science, The University of Tokyo, Bunkyo-ku Tokyo 113-0033, Japan

Abstract. A new version of the Earth system model of intermediate complexity (CANOPS-GRB) was developed for use in quantitatively assessing the dynamics and stability of atmospheric and oceanic chemistry over geologic timescales. The new release is designed to represent the coupled major element cycles of C, N, P, O, and S, as well as the global redox budget (GRB) in Earth’s exogenic (ocean-atmosphere-crust) system, using a process-based approach. This framework provides a mechanistic model of the evolution of atmospheric and oceanic O2 levels on geologic timescales and enables comparison with a wide variety of geological records to further constrain the processes driving Earth’s oxygenation. A complete detailed description of the resulting Earth system model and its new features are provided. The performance of CANOPS-GRB is then evaluated by comparing a steady-state simulation under present-day conditions with a comprehensive set of oceanic data and existing global estimates of bio-element cycling. The dynamic response of the model is also examined by varying phosphorus availability in the exogenic system. CANOPS-GRB reliably simulates the short- and long-term evolution of the coupled C-N-P-O2-S biogeochemical cycles and is generally applicable across any period of Earth’s history given suitable modifications to boundary conditions and forcing regime. The simple and adaptable design of the model also makes it useful to interrogate a wide range of problems related to Earth’s oxygenation history and Earth-like exoplanets more broadly. The model source code is available on GitHub, and represents a unique community tool for investigating the dynamics and stability of atmospheric and oceanic chemistry on long timescales.

Kazumi Ozaki et al.

Status: open (until 16 Jun 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on gmd-2022-12', Anonymous Referee #1, 25 Apr 2022 reply

Kazumi Ozaki et al.

Model code and software

CANOPS-GRBv1 Kazumi Ozaki

Kazumi Ozaki et al.


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Short summary
A new biogeochemical model (CANOPS-GRB v1.0) for assessing the redox stability and dynamics of the ocean-atmosphere system on geologic timescales has been developed. In this paper, we present a full description of the model and its performance. CANOPS-GRB is a useful tool for understanding the factors regulating atmospheric O2 levels and has the potential to greatly refine our current understanding of Earth’s oxygenation history.