An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic Atmosphere
Turbulence is a dominant feature of atmospheric motions. Despite its chaotic nature, it is observed to create and maintain coherent structures such as zonal jets and large-scale waves in the atmosphere. Previous studies on the self-organization of turbulence in a baroclinic two-layered fluid have sh...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-08-01
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| Series: | Environmental Sciences Proceedings |
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| Online Access: | https://www.mdpi.com/2673-4931/26/1/102 |
| _version_ | 1797241096953135104 |
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| author | Evangelos I. Stasinos Nikolaos A. Bakas |
| author_facet | Evangelos I. Stasinos Nikolaos A. Bakas |
| author_sort | Evangelos I. Stasinos |
| collection | DOAJ |
| description | Turbulence is a dominant feature of atmospheric motions. Despite its chaotic nature, it is observed to create and maintain coherent structures such as zonal jets and large-scale waves in the atmosphere. Previous studies on the self-organization of turbulence in a baroclinic two-layered fluid have shown that large-scale coherent structures emerge out of a homogeneous turbulent field through a collective type of instability with a preference for barotropic flows. That is, the barotropic coherent structures reorganize the turbulence in such a way as to reinforce themselves through a positive feedback and emerge in the flow. In this work, a statistical framework (S3T) is utilized in order to study the vorticity and thermal flux feedbacks underlying this instability. It is found that the feedbacks produced by the organization of incoherent barotropic and baroclinic eddies by the coherent emergent structures differ. For large stratification, the feedback that results from the organization of barotropic eddies by baroclinic coherent structures is negative and completely cancels out the positive feedback produced by the organization of the baroclinic eddies. On the contrary, the feedback resulting from the organization of the barotropic and the baroclinic turbulent eddies by the barotropic coherent structures do not cancel each other for most scales and lead to the emergence of these structures in the flow. The spatial features of the emerging coherent structures depend on the value of the non-dimensional planetary vorticity gradient. For small values of the gradient, the maximum value of the feedback is found for zonal jets, while for large values of the gradient, the maximum value of the feedback is found for Rossby waves. |
| first_indexed | 2024-04-24T18:17:54Z |
| format | Article |
| id | doaj.art-44618ab5082d47f18bc17e3e9f6ad36c |
| institution | Directory Open Access Journal |
| issn | 2673-4931 |
| language | English |
| last_indexed | 2024-04-24T18:17:54Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Environmental Sciences Proceedings |
| spelling | doaj.art-44618ab5082d47f18bc17e3e9f6ad36c2024-03-27T13:37:25ZengMDPI AGEnvironmental Sciences Proceedings2673-49312023-08-0126110210.3390/environsciproc2023026102An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic AtmosphereEvangelos I. Stasinos0Nikolaos A. Bakas1Laboratory of Meteorology and Climatology, Department of Physics, University of Ioannina, 45110 Ioannina, GreeceLaboratory of Meteorology and Climatology, Department of Physics, University of Ioannina, 45110 Ioannina, GreeceTurbulence is a dominant feature of atmospheric motions. Despite its chaotic nature, it is observed to create and maintain coherent structures such as zonal jets and large-scale waves in the atmosphere. Previous studies on the self-organization of turbulence in a baroclinic two-layered fluid have shown that large-scale coherent structures emerge out of a homogeneous turbulent field through a collective type of instability with a preference for barotropic flows. That is, the barotropic coherent structures reorganize the turbulence in such a way as to reinforce themselves through a positive feedback and emerge in the flow. In this work, a statistical framework (S3T) is utilized in order to study the vorticity and thermal flux feedbacks underlying this instability. It is found that the feedbacks produced by the organization of incoherent barotropic and baroclinic eddies by the coherent emergent structures differ. For large stratification, the feedback that results from the organization of barotropic eddies by baroclinic coherent structures is negative and completely cancels out the positive feedback produced by the organization of the baroclinic eddies. On the contrary, the feedback resulting from the organization of the barotropic and the baroclinic turbulent eddies by the barotropic coherent structures do not cancel each other for most scales and lead to the emergence of these structures in the flow. The spatial features of the emerging coherent structures depend on the value of the non-dimensional planetary vorticity gradient. For small values of the gradient, the maximum value of the feedback is found for zonal jets, while for large values of the gradient, the maximum value of the feedback is found for Rossby waves.https://www.mdpi.com/2673-4931/26/1/102Rossby wavesjetsbaroclinic turbulencebarotropic and baroclinic modescollective instabilityeddy–mean flow feedback |
| spellingShingle | Evangelos I. Stasinos Nikolaos A. Bakas An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic Atmosphere Environmental Sciences Proceedings Rossby waves jets baroclinic turbulence barotropic and baroclinic modes collective instability eddy–mean flow feedback |
| title | An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic Atmosphere |
| title_full | An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic Atmosphere |
| title_fullStr | An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic Atmosphere |
| title_full_unstemmed | An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic Atmosphere |
| title_short | An Investigation of the Dynamics Leading to the Emergence of Jets and Rossby Waves from a Background of Homogeneous Turbulence in a Baroclinic Atmosphere |
| title_sort | investigation of the dynamics leading to the emergence of jets and rossby waves from a background of homogeneous turbulence in a baroclinic atmosphere |
| topic | Rossby waves jets baroclinic turbulence barotropic and baroclinic modes collective instability eddy–mean flow feedback |
| url | https://www.mdpi.com/2673-4931/26/1/102 |
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