An unstable mode of the stratified atmosphere under the non-traditional Coriolis acceleration.
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| Title: | An unstable mode of the stratified atmosphere under the non-traditional Coriolis acceleration. |
|---|---|
| Authors: | Chew, Ray1 (AUTHOR), Schlutow, Mark2 (AUTHOR) mark.schlutow@bgc-jena.mpg.de, Klein, Rupert3 (AUTHOR) |
| Source: | Journal of Fluid Mechanics. 7/25/2023, Vol. 967, p1-32. 32p. |
| Subjects: | Atmosphere, Rotating fluid, Linear statistical models, Open-ended questions, Waves (Fluid mechanics) |
| Abstract: | The traditional approximation neglects the cosine components of the Coriolis acceleration, and this approximation has been widely used in the study of geophysical phenomena. However, the justification of the traditional approximation is questionable under a few circumstances. In particular, dynamics with substantial vertical velocities or geophysical phenomena in the tropics have non-negligible cosine Coriolis terms. Such cases warrant investigations with the non-traditional setting, i.e. the full Coriolis acceleration. In this manuscript, we study the effect of the non-traditional setting on an isothermal, hydrostatic and compressible atmosphere assuming a meridionally homogeneous flow. Employing linear stability analysis, we show that, given appropriate boundary conditions, i.e. a bottom boundary condition that allows for a vertical energy flux and non-reflecting boundary at the top, the atmosphere at rest becomes prone to a novel unstable mode. The validity of assuming a meridionally homogeneous flow is investigated via scale analysis. Numerical experiments were conducted, and Rayleigh damping was used as a numerical approximation for the non-reflecting top boundary. Our three main results are as follows: (i) experiments involving the full Coriolis terms exhibit an exponentially growing instability, yet experiments subjected to the traditional approximation remain stable; (ii) the experimental instability growth rate is close to the theoretical value; (iii) a perturbed version of the unstable mode arises even under sub-optimal bottom boundary conditions. Finally, we conclude our study by discussing the limitations, implications and remaining open questions. Specifically, the influence on numerical deep-atmosphere models and possible physical interpretations of the unstable mode are discussed. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Fluid Mechanics is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 166742949 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: An unstable mode of the stratified atmosphere under the non-traditional Coriolis acceleration. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Chew%2C+Ray%22">Chew, Ray</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Schlutow%2C+Mark%22">Schlutow, Mark</searchLink><relatesTo>2</relatesTo> (AUTHOR)<i> mark.schlutow@bgc-jena.mpg.de</i><br /><searchLink fieldCode="AR" term="%22Klein%2C+Rupert%22">Klein, Rupert</searchLink><relatesTo>3</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Fluid+Mechanics%22">Journal of Fluid Mechanics</searchLink>. 7/25/2023, Vol. 967, p1-32. 32p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Atmosphere%22">Atmosphere</searchLink><br /><searchLink fieldCode="DE" term="%22Rotating+fluid%22">Rotating fluid</searchLink><br /><searchLink fieldCode="DE" term="%22Linear+statistical+models%22">Linear statistical models</searchLink><br /><searchLink fieldCode="DE" term="%22Open-ended+questions%22">Open-ended questions</searchLink><br /><searchLink fieldCode="DE" term="%22Waves+%28Fluid+mechanics%29%22">Waves (Fluid mechanics)</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The traditional approximation neglects the cosine components of the Coriolis acceleration, and this approximation has been widely used in the study of geophysical phenomena. However, the justification of the traditional approximation is questionable under a few circumstances. In particular, dynamics with substantial vertical velocities or geophysical phenomena in the tropics have non-negligible cosine Coriolis terms. Such cases warrant investigations with the non-traditional setting, i.e. the full Coriolis acceleration. In this manuscript, we study the effect of the non-traditional setting on an isothermal, hydrostatic and compressible atmosphere assuming a meridionally homogeneous flow. Employing linear stability analysis, we show that, given appropriate boundary conditions, i.e. a bottom boundary condition that allows for a vertical energy flux and non-reflecting boundary at the top, the atmosphere at rest becomes prone to a novel unstable mode. The validity of assuming a meridionally homogeneous flow is investigated via scale analysis. Numerical experiments were conducted, and Rayleigh damping was used as a numerical approximation for the non-reflecting top boundary. Our three main results are as follows: (i) experiments involving the full Coriolis terms exhibit an exponentially growing instability, yet experiments subjected to the traditional approximation remain stable; (ii) the experimental instability growth rate is close to the theoretical value; (iii) a perturbed version of the unstable mode arises even under sub-optimal bottom boundary conditions. Finally, we conclude our study by discussing the limitations, implications and remaining open questions. Specifically, the influence on numerical deep-atmosphere models and possible physical interpretations of the unstable mode are discussed. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Fluid Mechanics is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1017/jfm.2023.474 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 32 StartPage: 1 Subjects: – SubjectFull: Atmosphere Type: general – SubjectFull: Rotating fluid Type: general – SubjectFull: Linear statistical models Type: general – SubjectFull: Open-ended questions Type: general – SubjectFull: Waves (Fluid mechanics) Type: general Titles: – TitleFull: An unstable mode of the stratified atmosphere under the non-traditional Coriolis acceleration. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Chew, Ray – PersonEntity: Name: NameFull: Schlutow, Mark – PersonEntity: Name: NameFull: Klein, Rupert IsPartOfRelationships: – BibEntity: Dates: – D: 25 M: 07 Text: 7/25/2023 Type: published Y: 2023 Identifiers: – Type: issn-print Value: 00221120 Numbering: – Type: volume Value: 967 Titles: – TitleFull: Journal of Fluid Mechanics Type: main |
| ResultId | 1 |
