Atmospheres & Climate

Climate Of High Obliquity Exo-terrestrial Planets With A Three-dimensional Cloud System Resolving Climate Model

By Keith Cowing
Press Release
October 12, 2022
Filed under , , , , ,
Climate Of High Obliquity Exo-terrestrial Planets With A Three-dimensional Cloud System Resolving Climate Model
Annual mean zonally averaged insolation distribution and surface temperature are shown in (a) and (b). Climatological seasonal march of zonal mean surface temperature in color (K) and the insolation in contours (W/m2 ) for (c) φ = 0◦ , (d) φ = 23.5 ◦ , (e) φ = 45◦ , and (f) φ = 60◦ . The global mean surface temperatures are shown in the upper right on each panel. All cases were run with a low resolution and parameterization for clouds.

Planetary climates are strongly affected by planetary orbital parameters such as obliquity, eccentricity, and precession.

In exoplanetary systems, exo-terrestrial planets should have various obliquities. High-obliquity planets would have extreme seasonal cycles due to the seasonal change of the distribution of the insolation. Here, we introduce the Non-hydrostatic ICosahedral Atmospheric Model(NICAM), a global cloud-resolving model, to investigate the climate of high-obliquity planets. This model can explicitly simulate a three-dimensional cloud distribution and vertical transports of water vapor. We simulated exo-terrestrial climates with high resolution using the supercomputer FUGAKU.

We assumed aqua-planet configurations with 1 bar of air as a background atmosphere, with four different obliquities (0∘, 23.5∘, 45∘, and 60∘). We ran two sets of simulations:

1) low-resolution (~ 220 km-mesh as the standard resolution of a general circulation model for exoplanetary science) with parametrization for cloud formation, and

2) high-resolution (~ 14 km-mesh) with an explicit cloud microphysics scheme.

Results suggest that high-resolution simulations with an explicit treatment of cloud microphysics reveal warmer climates due to less low cloud fraction and a large amount of water vapor in the atmosphere. It implies that treatments of cloud-related processes lead to a difference between different resolutions in climatic regimes in cases with high obliquities.

Takanori Kodama, Daisuke Takasuka, Sam Sherriff-Tadano, Takeshi Kuroda, Tomoki Miyakawa, Ayako Abe-Ouchi, Masaki Satoh

Comments: 18 pages, 9 figure, 2 tables. Accepted for publication in The Astrophysical Journal
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2210.05094 [astro-ph.EP] (or arXiv:2210.05094v1 [astro-ph.EP] for this version)
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Submission history
From: Takanori Kodama
[v1] Tue, 11 Oct 2022 02:13:02 UTC (9,068 KB)

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