Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below?
Abstract An unseasonal development of Equatorial Plasma Bubble (EPB)/Equatorial Spread-F (ESF) activity in a wide longitudinal sector over India and Southeast Asia during the post-sunset hours of 28 July 2014 has been investigated in detail using the multiple independent observations in this paper a...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2018-10-01
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| Series: | Progress in Earth and Planetary Science |
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| Online Access: | http://link.springer.com/article/10.1186/s40645-018-0218-1 |
| _version_ | 1818142806279979008 |
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| author | K. K. Ajith S. Tulasi Ram B. A. Carter S. Sathish Kumar M. Yamamoto T. Yokoyama S. Gurubaran S. Sripathi K. Hozumi K. Groves R. G. Caton |
| author_facet | K. K. Ajith S. Tulasi Ram B. A. Carter S. Sathish Kumar M. Yamamoto T. Yokoyama S. Gurubaran S. Sripathi K. Hozumi K. Groves R. G. Caton |
| author_sort | K. K. Ajith |
| collection | DOAJ |
| description | Abstract An unseasonal development of Equatorial Plasma Bubble (EPB)/Equatorial Spread-F (ESF) activity in a wide longitudinal sector over India and Southeast Asia during the post-sunset hours of 28 July 2014 has been investigated in detail using the multiple independent observations in this paper and a companion paper by (Prog Earth Planet Sci 5:10, 2018). This post-sunset ESF/EPB event was preceded by a substantial elevation of the equatorial F-layer due to strong pre-reversal enhancement (PRE) during the season which is climatologically unfavorable for strong PRE and post-sunset EPBs. In this paper, it is found that a strong equatorward meridional neutral wind at off-equatorial E-region and enhanced longitudinal gradient of equatorial electrojet appear to be the responsible candidates for the enhanced PRE and EPB development on 28 July 2014. These changes in the local wind system and PRE are found to have an apparent connection with the planetary wave forces of lower atmospheric origin. Both the post-sunset height rise (PSSR) and lower thermospheric meridional neutral wind consistently exhibit quasi-2-day planetary wave-like oscillations during 20–31 July 2014 with maximum amplitudes on 28 July 2014. This study emphasizes the role of planetary wave forces from the lower atmosphere that can alter the local neutral wind system and E-region conductivities that may lead to the development of strong PRE and EPB activity which were otherwise climatologically unfavorable for post-sunset EPB/ESF development. |
| first_indexed | 2024-12-11T11:21:37Z |
| format | Article |
| id | doaj.art-cf7ace494ce24250850c4a77904e0001 |
| institution | Directory Open Access Journal |
| issn | 2197-4284 |
| language | English |
| last_indexed | 2024-12-11T11:21:37Z |
| publishDate | 2018-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Progress in Earth and Planetary Science |
| spelling | doaj.art-cf7ace494ce24250850c4a77904e00012022-12-22T01:09:09ZengSpringerOpenProgress in Earth and Planetary Science2197-42842018-10-015111510.1186/s40645-018-0218-1Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below?K. K. Ajith0S. Tulasi Ram1B. A. Carter2S. Sathish Kumar3M. Yamamoto4T. Yokoyama5S. Gurubaran6S. Sripathi7K. Hozumi8K. Groves9R. G. Caton10Indian Institute of GeomagnetismIndian Institute of GeomagnetismRMIT UniversityEquatorial Geophysical Research Laboratory, Indian Institute of GeomagnetismResearch Institute for Sustainable Humanosphere (RISH), Kyoto UniversityNational institute of Information and Communications TechnologyIndian Institute of GeomagnetismIndian Institute of GeomagnetismNational institute of Information and Communications TechnologyBoston CollegeSpace Vehicles Directorate, Air Force Research Laboratory, Kirtland AFBAbstract An unseasonal development of Equatorial Plasma Bubble (EPB)/Equatorial Spread-F (ESF) activity in a wide longitudinal sector over India and Southeast Asia during the post-sunset hours of 28 July 2014 has been investigated in detail using the multiple independent observations in this paper and a companion paper by (Prog Earth Planet Sci 5:10, 2018). This post-sunset ESF/EPB event was preceded by a substantial elevation of the equatorial F-layer due to strong pre-reversal enhancement (PRE) during the season which is climatologically unfavorable for strong PRE and post-sunset EPBs. In this paper, it is found that a strong equatorward meridional neutral wind at off-equatorial E-region and enhanced longitudinal gradient of equatorial electrojet appear to be the responsible candidates for the enhanced PRE and EPB development on 28 July 2014. These changes in the local wind system and PRE are found to have an apparent connection with the planetary wave forces of lower atmospheric origin. Both the post-sunset height rise (PSSR) and lower thermospheric meridional neutral wind consistently exhibit quasi-2-day planetary wave-like oscillations during 20–31 July 2014 with maximum amplitudes on 28 July 2014. This study emphasizes the role of planetary wave forces from the lower atmosphere that can alter the local neutral wind system and E-region conductivities that may lead to the development of strong PRE and EPB activity which were otherwise climatologically unfavorable for post-sunset EPB/ESF development.http://link.springer.com/article/10.1186/s40645-018-0218-1Equatorial plasma bubblesPre-reversal enhancementNeutral winds |
| spellingShingle | K. K. Ajith S. Tulasi Ram B. A. Carter S. Sathish Kumar M. Yamamoto T. Yokoyama S. Gurubaran S. Sripathi K. Hozumi K. Groves R. G. Caton Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below? Progress in Earth and Planetary Science Equatorial plasma bubbles Pre-reversal enhancement Neutral winds |
| title | Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below? |
| title_full | Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below? |
| title_fullStr | Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below? |
| title_full_unstemmed | Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below? |
| title_short | Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 2. Forcing from below? |
| title_sort | unseasonal development of post sunset f region irregularities over southeast asia on 28 july 2014 2 forcing from below |
| topic | Equatorial plasma bubbles Pre-reversal enhancement Neutral winds |
| url | http://link.springer.com/article/10.1186/s40645-018-0218-1 |
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