Equatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation Model
We investigate the characteristics of equatorial waves associated with the maintenance of superrotation in the stratosphere of a Titan general circulation model. A variety of equatorial waves are present in the model atmosphere, including equatorial Kelvin waves, equatorial Rossby waves, and mixed R...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Planetary Science Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/PSJ/ace76f |
| _version_ | 1797328381144989696 |
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| author | Neil T. Lewis Nicholas A. Lombardo Peter L. Read Juan M. Lora |
| author_facet | Neil T. Lewis Nicholas A. Lombardo Peter L. Read Juan M. Lora |
| author_sort | Neil T. Lewis |
| collection | DOAJ |
| description | We investigate the characteristics of equatorial waves associated with the maintenance of superrotation in the stratosphere of a Titan general circulation model. A variety of equatorial waves are present in the model atmosphere, including equatorial Kelvin waves, equatorial Rossby waves, and mixed Rossby–gravity waves. In the upper stratosphere, acceleration of superrotation is strongest around solstice and is due to interaction between equatorial Kelvin waves and Rossby-type waves in winter hemisphere midlatitudes. The existence of this “Rossby–Kelvin”-type wave appears to depend on strong meridional shear of the background zonal wind that occurs in the upper stratosphere at times away from the equinoxes. In the lower stratosphere, acceleration of superrotation occurs throughout the year and is partially induced by equatorial Rossby waves, which we speculate are generated by quasigeostrophic barotropic instability. Acceleration of superrotation is generally due to waves with phase speeds close to the zonal velocity of the mean flow. Consequently, they have short vertical wavelengths that are close to the model’s vertical grid scale and therefore likely to be not properly represented. We suggest that this may be a common issue among Titan general circulation models that should be addressed by future model development. |
| first_indexed | 2024-03-08T06:51:02Z |
| format | Article |
| id | doaj.art-60554e14bf0146b7828d771728fcdd7a |
| institution | Directory Open Access Journal |
| issn | 2632-3338 |
| language | English |
| last_indexed | 2024-03-08T06:51:02Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Planetary Science Journal |
| spelling | doaj.art-60554e14bf0146b7828d771728fcdd7a2024-02-03T06:58:29ZengIOP PublishingThe Planetary Science Journal2632-33382023-01-014814910.3847/PSJ/ace76fEquatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation ModelNeil T. Lewis0https://orcid.org/0000-0002-3724-5728Nicholas A. Lombardo1https://orcid.org/0000-0001-8621-6520Peter L. Read2Juan M. Lora3https://orcid.org/0000-0001-9925-1050Atmospheric, Oceanic and Planetary Physics, University of Oxford , Oxford, UK; Department of Mathematics and Statistics, University of Exeter , Exeter, UKDepartment of Earth and Planetary Sciences, Yale University , New Haven, CT, USAAtmospheric, Oceanic and Planetary Physics, University of Oxford , Oxford, UKDepartment of Earth and Planetary Sciences, Yale University , New Haven, CT, USAWe investigate the characteristics of equatorial waves associated with the maintenance of superrotation in the stratosphere of a Titan general circulation model. A variety of equatorial waves are present in the model atmosphere, including equatorial Kelvin waves, equatorial Rossby waves, and mixed Rossby–gravity waves. In the upper stratosphere, acceleration of superrotation is strongest around solstice and is due to interaction between equatorial Kelvin waves and Rossby-type waves in winter hemisphere midlatitudes. The existence of this “Rossby–Kelvin”-type wave appears to depend on strong meridional shear of the background zonal wind that occurs in the upper stratosphere at times away from the equinoxes. In the lower stratosphere, acceleration of superrotation occurs throughout the year and is partially induced by equatorial Rossby waves, which we speculate are generated by quasigeostrophic barotropic instability. Acceleration of superrotation is generally due to waves with phase speeds close to the zonal velocity of the mean flow. Consequently, they have short vertical wavelengths that are close to the model’s vertical grid scale and therefore likely to be not properly represented. We suggest that this may be a common issue among Titan general circulation models that should be addressed by future model development.https://doi.org/10.3847/PSJ/ace76fTitanPlanetary atmospheresPlanetary science |
| spellingShingle | Neil T. Lewis Nicholas A. Lombardo Peter L. Read Juan M. Lora Equatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation Model The Planetary Science Journal Titan Planetary atmospheres Planetary science |
| title | Equatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation Model |
| title_full | Equatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation Model |
| title_fullStr | Equatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation Model |
| title_full_unstemmed | Equatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation Model |
| title_short | Equatorial Waves and Superrotation in the Stratosphere of a Titan General Circulation Model |
| title_sort | equatorial waves and superrotation in the stratosphere of a titan general circulation model |
| topic | Titan Planetary atmospheres Planetary science |
| url | https://doi.org/10.3847/PSJ/ace76f |
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