Investigations on Concentric Gravity Wave Sources Over the Brazilian Equatorial Region.
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| Title: | Investigations on Concentric Gravity Wave Sources Over the Brazilian Equatorial Region. |
|---|---|
| Authors: | Nyassor, P. K.1 (AUTHOR) prosper.nyassor@inpe.br, Wrasse, C. M.1 (AUTHOR), Paulino, I.2 (AUTHOR), Gobbi, D.1 (AUTHOR), Yiğit, E.3 (AUTHOR), Takahashi, H.1 (AUTHOR), Batista, P. P.4 (AUTHOR), Naccarato, K. P.5 (AUTHOR), Buriti, R. A.2 (AUTHOR), Paulino, A. R.6 (AUTHOR), Barros, D.1 (AUTHOR), Figueiredo, C. A. O. B.1 (AUTHOR) |
| Source: | Journal of Geophysical Research. Atmospheres. 9/16/2022, Vol. 127 Issue 17, p1-20. 20p. |
| Subject Terms: | *Middle atmosphere, *Upper atmosphere, Gravity waves, Atmospheric boundary layer, Ray tracing, Thermosphere, Atmospheric acoustics |
| Abstract: | Observations of concentric gravity waves (CGWs) in the OH airglow emission over the Brazilian equatorial region are presented. An all‐sky imager installed at São João do Cariri [7.4°S, 36.5°W] was used to acquire near‐infrared OH images. Using over 19 years of observational data from 2000 to 2019, more than 1,052 clear sky nights of airglow data were acquired with a total of 25 observed CGW cases. Three CGW events were selected for this study. These waves had small‐scale characteristics and well‐defined concentric structures. The selected CGW events showed horizontal wavelengths λH ∼ 31.9, 42.5, and 30.9 km, horizontal phase speeds cH ∼ 49.2, 57.6, and 74.1 m/s, and periods τ ∼ 10.8, 12.3, and 7.0 min, respectively. The CGW structures were well defined, with coherent wave patterns expanding concentrically from the source point, with the observed events having semi‐circle or arc‐like and semi‐elliptical shapes. We found the occurrence of the CGWs to coincide with the seasons of intense tropospheric convective activity and low background winds. This suggests little or no wave breaking, critical level absorption, and filtering or reflection, thereby allowing the CGWs to propagate up to the mesosphere and lower thermosphere region. Using backward ray tracing, we also found the positions and times where and when the ray paths reached the tropopause. The tropopause positions and times of two of the CGW events coincide with active convective systems with cold cloud top temperatures. However, the tropopause position of one of the 3 CGW events did not coincide with any active convective system, suggesting that this CGW was most likely generated in‐situ. Plain Language Summary: Point‐like convective overshooting of the tropopause by 1–3 km into the stratosphere can excite GWs with concentric shapes. These waves can propagate to the middle and upper atmosphere where they are observed using imaging techniques. Also, some GWs with concentric shapes are excited when GWs primarily generated in the lower atmosphere dissipate or break. To study the propagation of these concentric gravity waves (CGWs) in the atmosphere from the observation altitudes to their possible source locations in the troposphere, the ray tracing model was used. The ray tracing results revealed that the state and impact of the background winds on the propagation of the CGWs differ for each of the three cases presented. Among the three CGWs, it was evident that the event with relatively strong and variable wind, the vertical, horizontal, and temporal propagations were significantly affected. The stopping points of the ray paths of the waves used to locate the possible source positions of the CGWs showed that the ray paths of two out of the three CGW cases stopped near deep convective systems in the troposphere, indicating these systems are their possible source. The ray path of the remaining CGW case stopped in the troposphere but no deep convective system was found close to the stopping point, thus suggesting this wave was not convectively generated. Key Points: Concentric gravity waves over the Brazilian equatorial region are presentedThe concentric wavefront configurations were examined relative to their propagation from the observation to the source positionsThe unknown source of one of the concentric GWs without a nearby deep convective system is investigated [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Geophysical Research. Atmospheres is the property of Wiley-Blackwell 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.) | |
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| Items | – Name: Title Label: Title Group: Ti Data: Investigations on Concentric Gravity Wave Sources Over the Brazilian Equatorial Region. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Nyassor%2C+P%2E+K%2E%22">Nyassor, P. K.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> prosper.nyassor@inpe.br</i><br /><searchLink fieldCode="AR" term="%22Wrasse%2C+C%2E+M%2E%22">Wrasse, C. M.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Paulino%2C+I%2E%22">Paulino, I.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Gobbi%2C+D%2E%22">Gobbi, D.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Yiğit%2C+E%2E%22">Yiğit, E.</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Takahashi%2C+H%2E%22">Takahashi, H.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Batista%2C+P%2E+P%2E%22">Batista, P. P.</searchLink><relatesTo>4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Naccarato%2C+K%2E+P%2E%22">Naccarato, K. P.</searchLink><relatesTo>5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Buriti%2C+R%2E+A%2E%22">Buriti, R. A.</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Paulino%2C+A%2E+R%2E%22">Paulino, A. R.</searchLink><relatesTo>6</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Barros%2C+D%2E%22">Barros, D.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Figueiredo%2C+C%2E+A%2E+O%2E+B%2E%22">Figueiredo, C. A. O. B.</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Geophysical+Research%2E+Atmospheres%22">Journal of Geophysical Research. Atmospheres</searchLink>. 9/16/2022, Vol. 127 Issue 17, p1-20. 20p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Middle+atmosphere%22">Middle atmosphere</searchLink><br />*<searchLink fieldCode="DE" term="%22Upper+atmosphere%22">Upper atmosphere</searchLink><br /><searchLink fieldCode="DE" term="%22Gravity+waves%22">Gravity waves</searchLink><br /><searchLink fieldCode="DE" term="%22Atmospheric+boundary+layer%22">Atmospheric boundary layer</searchLink><br /><searchLink fieldCode="DE" term="%22Ray+tracing%22">Ray tracing</searchLink><br /><searchLink fieldCode="DE" term="%22Thermosphere%22">Thermosphere</searchLink><br /><searchLink fieldCode="DE" term="%22Atmospheric+acoustics%22">Atmospheric acoustics</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Observations of concentric gravity waves (CGWs) in the OH airglow emission over the Brazilian equatorial region are presented. An all‐sky imager installed at São João do Cariri [7.4°S, 36.5°W] was used to acquire near‐infrared OH images. Using over 19 years of observational data from 2000 to 2019, more than 1,052 clear sky nights of airglow data were acquired with a total of 25 observed CGW cases. Three CGW events were selected for this study. These waves had small‐scale characteristics and well‐defined concentric structures. The selected CGW events showed horizontal wavelengths λH ∼ 31.9, 42.5, and 30.9 km, horizontal phase speeds cH ∼ 49.2, 57.6, and 74.1 m/s, and periods τ ∼ 10.8, 12.3, and 7.0 min, respectively. The CGW structures were well defined, with coherent wave patterns expanding concentrically from the source point, with the observed events having semi‐circle or arc‐like and semi‐elliptical shapes. We found the occurrence of the CGWs to coincide with the seasons of intense tropospheric convective activity and low background winds. This suggests little or no wave breaking, critical level absorption, and filtering or reflection, thereby allowing the CGWs to propagate up to the mesosphere and lower thermosphere region. Using backward ray tracing, we also found the positions and times where and when the ray paths reached the tropopause. The tropopause positions and times of two of the CGW events coincide with active convective systems with cold cloud top temperatures. However, the tropopause position of one of the 3 CGW events did not coincide with any active convective system, suggesting that this CGW was most likely generated in‐situ. Plain Language Summary: Point‐like convective overshooting of the tropopause by 1–3 km into the stratosphere can excite GWs with concentric shapes. These waves can propagate to the middle and upper atmosphere where they are observed using imaging techniques. Also, some GWs with concentric shapes are excited when GWs primarily generated in the lower atmosphere dissipate or break. To study the propagation of these concentric gravity waves (CGWs) in the atmosphere from the observation altitudes to their possible source locations in the troposphere, the ray tracing model was used. The ray tracing results revealed that the state and impact of the background winds on the propagation of the CGWs differ for each of the three cases presented. Among the three CGWs, it was evident that the event with relatively strong and variable wind, the vertical, horizontal, and temporal propagations were significantly affected. The stopping points of the ray paths of the waves used to locate the possible source positions of the CGWs showed that the ray paths of two out of the three CGW cases stopped near deep convective systems in the troposphere, indicating these systems are their possible source. The ray path of the remaining CGW case stopped in the troposphere but no deep convective system was found close to the stopping point, thus suggesting this wave was not convectively generated. Key Points: Concentric gravity waves over the Brazilian equatorial region are presentedThe concentric wavefront configurations were examined relative to their propagation from the observation to the source positionsThe unknown source of one of the concentric GWs without a nearby deep convective system is investigated [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Geophysical Research. Atmospheres is the property of Wiley-Blackwell 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: 10.1029/2021JD035149 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 20 StartPage: 1 Subjects: – SubjectFull: Middle atmosphere Type: general – SubjectFull: Upper atmosphere Type: general – SubjectFull: Gravity waves Type: general – SubjectFull: Atmospheric boundary layer Type: general – SubjectFull: Ray tracing Type: general – SubjectFull: Thermosphere Type: general – SubjectFull: Atmospheric acoustics Type: general Titles: – TitleFull: Investigations on Concentric Gravity Wave Sources Over the Brazilian Equatorial Region. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Nyassor, P. K. – PersonEntity: Name: NameFull: Wrasse, C. M. – PersonEntity: Name: NameFull: Paulino, I. – PersonEntity: Name: NameFull: Gobbi, D. – PersonEntity: Name: NameFull: Yiğit, E. – PersonEntity: Name: NameFull: Takahashi, H. – PersonEntity: Name: NameFull: Batista, P. P. – PersonEntity: Name: NameFull: Naccarato, K. P. – PersonEntity: Name: NameFull: Buriti, R. A. – PersonEntity: Name: NameFull: Paulino, A. R. – PersonEntity: Name: NameFull: Barros, D. – PersonEntity: Name: NameFull: Figueiredo, C. A. O. B. IsPartOfRelationships: – BibEntity: Dates: – D: 16 M: 09 Text: 9/16/2022 Type: published Y: 2022 Identifiers: – Type: issn-print Value: 2169897X Numbering: – Type: volume Value: 127 – Type: issue Value: 17 Titles: – TitleFull: Journal of Geophysical Research. Atmospheres Type: main |
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