SURFER v2.9 with AMOC Tipping Calibration Module (ATCM)

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This readme file was generated on [2025-01-10] by Amaury Laridon

Last updated: [2025-01-10].

DOI : insert

This repository contains the SURFER v2.9 models that integrates the AMOC Tipping Calibration Module (ATCM) used and described in Laridon et al.[1] "Connecting Complex and Simplified Models of Tipping Elements: A Nonlinear Two-Forcing Emulator for the Atlantic Meridional Overturning Circulation"

The ATCM is a tipping element emulator of the AMOC based on the normal form of a double-fold bifurcation. It is a two forcing variables system that allows to simulate the evolution of the AMOC under the temperature anomaly forcing and the freshwater flux forcing coming from the melting of the Greenland Ice Sheet. The ATCM can be calibrate based on two calibration experiments coming from a complex model. The calibration module is a generalization of the one present in Martinez Monteiro et al.[1,4].

SURFER is a reduced complexity climate model with a process-based carbon cycle [1,2]. We integrate the ATCM into SURFER v2.9 to obtain a tipping element emulator of the AMOC integrate into a reduced complexity climate model.

ATCM

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ATCM.ipynb is the Jupyter Notebook that contains the Python script of the AMOC Tipping Calibration Module. This notebook contains :

• Mathematical framework behind the AMOC Tipping Calibration Module (ATCM)
• The ATCM
• The ATCM Calibration Validation test
• cGENIE Emulation
  • Calibration of the internal dynamics parameters
  • Calibration of the characteristic time scale parameter
• ATCM validation on an other cGENIE experiment

How to run

1. Change the base_path variable to the main directory in which you saved this repository.
2. Download the cGENIE simulations Zenodo
3. Upload the cGENIE simulations in the base_path/data/cGENIE simulations/Paper simulations/ directory
4. Run the Notebook.

SURFER v2.9 with ATCM

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SURFER_v2.9_ATCM.ipynb is the Jupyter Notebook that contains the Python script of v2.9 of SURFER climate model with the ATCM.

How to run

1. Change the base_path variable to the main directory in which you saved this repository.
2. Run the Notebook.

Version

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Version January 2025

Authors

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Amaury Laridon(1), Victor Couplet(2), Justin Gérard(2), Wim Thiery (1), Michel Crucifix(2)

(1) Vrije Universiteit Brussel, Department of Water and Climate, bclimate Research Group, Brussels, Belgium.

(2) UCLouvain, Earth and Life Institute, Louvain-La-Neuve, Belgium.

Contact author : [email protected]

References

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• [1] A. Laridon, V. Couplet, J. Gérard, W. Thiery, M. Crucifix, "Connecting Complex and Simplified Models of Tipping Elements: A Nonlinear Two-Forcing Emulator for the Atlantic Meridional Overturning Circulation", Open Research Europe, Jan. 2025, doi : ?

• [2] M. Martínez Montero, M. Crucifix, V. Couplet, N. Brede, and N. Botta, ‘SURFER v2.0: a flexible and simple model linking anthropogenic CO2 emissions and solar radiation modification to ocean acidification and sea level rise’, Geoscientific Model Development, vol. 15, no. 21, pp. 8059–8084, Nov. 2022, doi: 10.5194/gmd-15-8059-2022.

• [3] V. Couplet, M. Montero, and M. Crucifix, SURFER v3.0: a fast model with ice sheet tipping points and carbon cycle feedbacks for short and long-term climate scenarios. 2024. doi: 10.5194/egusphere-2024-2279.

• [4] V. Couplet, N. Wunderling, and M. Crucifix, ‘Tipping interactions and cascades on multimillennial time scales in a model of reduced complexity’, 2024.