General Circulation Model Errors Are Variable across Exoclimate Parameter Spaces

Kopparla, Pushkar; Deitrick, Russell; Heng, Kevin; Mendonça, João M.; Hammond, Mark (2021). General Circulation Model Errors Are Variable across Exoclimate Parameter Spaces. Astrophysical journal, 923(1), p. 39. Institute of Physics Publishing IOP 10.3847/1538-4357/ac2d27

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General circulation models (GCMs) are often used to explore exoclimate parameter spaces and classify atmospheric circulation regimes. Models are tuned to give reasonable climate states for standard test cases, such as the Held–Suarez test, and then used to simulate diverse exoclimates by varying input parameters such as rotation rates, instellation, atmospheric optical properties, frictional timescales, and so on. In such studies, there is an implicit assumption that the model works reasonably well for the standard test case will be credible at all points in an arbitrarily wide parameter space. Here, we test this assumption using the open-source GCM THOR to simulate atmospheric circulation on tidally locked Earth-like planets with rotation periods of 0.1–100 days. We find that the model error, as quantified by the ratio between physical and spurious numerical contributions to the angular momentum balance, is extremely variable across this range of rotation periods with some cases where numerical errors are the dominant component. Increasing model grid resolution does improve errors, but using a higher-order numerical diffusion scheme can sometimes magnify errors for finite-volume dynamical solvers. We further show that to minimize error and make the angular momentum balance more physical within our model, the surface friction timescale must be smaller than the rotational timescale.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Kopparla, Pushkar, Deitrick, Russell John, Heng, Kevin

Subjects:

500 Science > 520 Astronomy
500 Science > 530 Physics

ISSN:

0004-637X

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

05 May 2022 11:36

Last Modified:

05 Dec 2022 16:19

Publisher DOI:

10.3847/1538-4357/ac2d27

BORIS DOI:

10.48350/169733

URI:

https://boris.unibe.ch/id/eprint/169733

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