The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region
This investigation presents an initial attempt to analyze a full year of daily ionosonde observations relevant to the determination of plasma densities, tidal structures, and ion transports in the equatorial anomaly region of the lower ionosphere. Particular focus is on the intermediate laye...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2003-04-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/21/1039/2003/angeo-21-1039-2003.pdf |
| _version_ | 1818855626430742528 |
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| author | C.-C. Lee J.-Y. Liu J.-Y. Liu C.-J. Pan H.-H. Hsu |
| author_facet | C.-C. Lee J.-Y. Liu J.-Y. Liu C.-J. Pan H.-H. Hsu |
| author_sort | C.-C. Lee |
| collection | DOAJ |
| description | This investigation
presents an initial attempt to analyze a full year of daily ionosonde
observations relevant to the determination of plasma densities, tidal
structures, and ion transports in the equatorial anomaly region of the lower
ionosphere. Particular focus is on the intermediate layers, their seasonal and
diurnal variations, and cause-effect relationships. The ionogram database was
recorded using a digisonde portable sounder (DPS) at National Central
University (NCU, 24 °58' N, 121°11' E) during 1996. Statistical results
indicate that the intermediate layers appear primarily during the daytime of
the spring/winter months. The monthly median height characteristics reveal that
the layers descend from high to low altitudes and different tidal motions
control the layers in different months. Generally, the semi-diurnal and
quarter-diurnal tides, which cause ionization convergence, are mainly in the
spring/winter and summer/autumn months, respectively. Variations in the
electron densities of the layers also indicate that the density increases could
result from a great number of molecular and metallic ions. Furthermore, a novel
approach to ionogram presentation is introduced to investigate the intermediate
layers. This approach allows the DPS to characterize the detailed daily
information of the intermediate layers.<br><br><b>Key words. </b>Ionosphere (equatorial
ionosphere; ionosphere-atmosphere interactions; ionospheric irregularities) |
| first_indexed | 2024-12-19T08:11:36Z |
| format | Article |
| id | doaj.art-103fbf98b2b940d99825126a8a6ee01e |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-19T08:11:36Z |
| publishDate | 2003-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-103fbf98b2b940d99825126a8a6ee01e2022-12-21T20:29:36ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762003-04-01211039104510.5194/angeo-21-1039-2003The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly regionC.-C. Lee0J.-Y. Liu1J.-Y. Liu2C.-J. Pan3H.-H. Hsu4Institute of Space Science, National Central University, NO. 300, Jung-da Rd., Chung-Li 320, TaiwanCenter for Space and Remote Sensing Research, National Central University, NO. 300, Jung-da Rd. Chung-Li 320, TaiwanInstitute of Space Science, National Central University, NO. 300, Jung-da Rd., Chung-Li 320, TaiwanInstitute of Space Science, National Central University, NO. 300, Jung-da Rd., Chung-Li 320, TaiwanInstitute of Space Science, National Central University, NO. 300, Jung-da Rd., Chung-Li 320, TaiwanThis investigation presents an initial attempt to analyze a full year of daily ionosonde observations relevant to the determination of plasma densities, tidal structures, and ion transports in the equatorial anomaly region of the lower ionosphere. Particular focus is on the intermediate layers, their seasonal and diurnal variations, and cause-effect relationships. The ionogram database was recorded using a digisonde portable sounder (DPS) at National Central University (NCU, 24 °58' N, 121°11' E) during 1996. Statistical results indicate that the intermediate layers appear primarily during the daytime of the spring/winter months. The monthly median height characteristics reveal that the layers descend from high to low altitudes and different tidal motions control the layers in different months. Generally, the semi-diurnal and quarter-diurnal tides, which cause ionization convergence, are mainly in the spring/winter and summer/autumn months, respectively. Variations in the electron densities of the layers also indicate that the density increases could result from a great number of molecular and metallic ions. Furthermore, a novel approach to ionogram presentation is introduced to investigate the intermediate layers. This approach allows the DPS to characterize the detailed daily information of the intermediate layers.<br><br><b>Key words. </b>Ionosphere (equatorial ionosphere; ionosphere-atmosphere interactions; ionospheric irregularities)https://www.ann-geophys.net/21/1039/2003/angeo-21-1039-2003.pdf |
| spellingShingle | C.-C. Lee J.-Y. Liu J.-Y. Liu C.-J. Pan H.-H. Hsu The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region Annales Geophysicae |
| title | The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region |
| title_full | The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region |
| title_fullStr | The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region |
| title_full_unstemmed | The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region |
| title_short | The intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region |
| title_sort | intermediate layers and associated tidal motions observed by a digisonde in the equatorial anomaly region |
| url | https://www.ann-geophys.net/21/1039/2003/angeo-21-1039-2003.pdf |
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