Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and Digisonde
Abstract Daytime equatorial spread F (ESF) is not as common as nighttime ESF due to the presence of a highly conducting E‐layer during the daytime which counteracts the development of F‐layer plasma irregularities. This study presents two rare daytime ESF‐like events which occurred over an interval...
Saved in:
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2021-04-01
|
| Series: | Space Weather |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2020SW002676 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1841536351722274816 |
|---|---|
| author | B. Olugbon E. O. Oyeyemi A. Kascheyev A. B. Rabiu A. A. Obafaye O. O. Odeyemi A. O. Adewale |
| author_facet | B. Olugbon E. O. Oyeyemi A. Kascheyev A. B. Rabiu A. A. Obafaye O. O. Odeyemi A. O. Adewale |
| author_sort | B. Olugbon |
| collection | DOAJ |
| description | Abstract Daytime equatorial spread F (ESF) is not as common as nighttime ESF due to the presence of a highly conducting E‐layer during the daytime which counteracts the development of F‐layer plasma irregularities. This study presents two rare daytime ESF‐like events which occurred over an interval ∼2 h and were detected by the HF Doppler receiver located in Lagos (LAG: geographic: 3.27°E, 6.48°N; dip latitude −1.72°) and the Lowell Digisonde at Ilorin (ILR; 4.68°E, 8.50°N; dip latitude −1.25°), managed by Lowell GIRO Data Center (LGDC). Analysis of the first event revealed ∼30 min periodic oscillations in iso‐heights of ionospheric electron density. Shorter period (∼15 min) oscillations appeared simultaneously in HF Doppler measurements and these oscillations lasted nearly 3 h. Close inspection of the ionograms from ILR during this interval (1500–1800 UT) showed the occurrence of small‐scale spreading in the F‐layer trace which varied in altitude as the disturbance progressed. Computation of the linear growth rate of the collisional Rayleigh‐Taylor instability showed that the plasma instability was seeded by a traveling ionospheric disturbance (TID). The characteristics of the second event suggest that horizontal stratifications in plasma density distribution at the reflecting ionospheric layer were responsible for the spread F traces in the ionograms. Analysis of GPS TEC data from Nigeria during these events revealed the presence of wave structures consistent with TIDs. |
| format | Article |
| id | doaj-art-add8df83be08438f8b1f40424b435e5c |
| institution | Kabale University |
| issn | 1542-7390 |
| language | English |
| publishDate | 2021-04-01 |
| publisher | Wiley |
| record_format | Article |
| series | Space Weather |
| spelling | doaj-art-add8df83be08438f8b1f40424b435e5c2025-01-14T16:31:28ZengWileySpace Weather1542-73902021-04-01194n/an/a10.1029/2020SW002676Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and DigisondeB. Olugbon0E. O. Oyeyemi1A. Kascheyev2A. B. Rabiu3A. A. Obafaye4O. O. Odeyemi5A. O. Adewale6Department of Physics University of Lagos Lagos NigeriaDepartment of Physics University of Lagos Lagos NigeriaPhysics Department University of New Brunswick Fredericton CanadaCenter for Atmospheric Research National Space Research and Development Agency Kogi State University Campus Anyigba NigeriaCenter for Atmospheric Research National Space Research and Development Agency Kogi State University Campus Anyigba NigeriaDepartment of Physics University of Lagos Lagos NigeriaDepartment of Physics University of Lagos Lagos NigeriaAbstract Daytime equatorial spread F (ESF) is not as common as nighttime ESF due to the presence of a highly conducting E‐layer during the daytime which counteracts the development of F‐layer plasma irregularities. This study presents two rare daytime ESF‐like events which occurred over an interval ∼2 h and were detected by the HF Doppler receiver located in Lagos (LAG: geographic: 3.27°E, 6.48°N; dip latitude −1.72°) and the Lowell Digisonde at Ilorin (ILR; 4.68°E, 8.50°N; dip latitude −1.25°), managed by Lowell GIRO Data Center (LGDC). Analysis of the first event revealed ∼30 min periodic oscillations in iso‐heights of ionospheric electron density. Shorter period (∼15 min) oscillations appeared simultaneously in HF Doppler measurements and these oscillations lasted nearly 3 h. Close inspection of the ionograms from ILR during this interval (1500–1800 UT) showed the occurrence of small‐scale spreading in the F‐layer trace which varied in altitude as the disturbance progressed. Computation of the linear growth rate of the collisional Rayleigh‐Taylor instability showed that the plasma instability was seeded by a traveling ionospheric disturbance (TID). The characteristics of the second event suggest that horizontal stratifications in plasma density distribution at the reflecting ionospheric layer were responsible for the spread F traces in the ionograms. Analysis of GPS TEC data from Nigeria during these events revealed the presence of wave structures consistent with TIDs.https://doi.org/10.1029/2020SW002676equatorialionosphereirregularitiesspread Ftraveling ionospheric disturbances |
| spellingShingle | B. Olugbon E. O. Oyeyemi A. Kascheyev A. B. Rabiu A. A. Obafaye O. O. Odeyemi A. O. Adewale Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and Digisonde Space Weather equatorial ionosphere irregularities spread F traveling ionospheric disturbances |
| title | Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and Digisonde |
| title_full | Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and Digisonde |
| title_fullStr | Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and Digisonde |
| title_full_unstemmed | Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and Digisonde |
| title_short | Daytime Equatorial Spread F‐Like Irregularities Detected by HF Doppler Receiver and Digisonde |
| title_sort | daytime equatorial spread f like irregularities detected by hf doppler receiver and digisonde |
| topic | equatorial ionosphere irregularities spread F traveling ionospheric disturbances |
| url | https://doi.org/10.1029/2020SW002676 |
| work_keys_str_mv | AT bolugbon daytimeequatorialspreadflikeirregularitiesdetectedbyhfdopplerreceiveranddigisonde AT eooyeyemi daytimeequatorialspreadflikeirregularitiesdetectedbyhfdopplerreceiveranddigisonde AT akascheyev daytimeequatorialspreadflikeirregularitiesdetectedbyhfdopplerreceiveranddigisonde AT abrabiu daytimeequatorialspreadflikeirregularitiesdetectedbyhfdopplerreceiveranddigisonde AT aaobafaye daytimeequatorialspreadflikeirregularitiesdetectedbyhfdopplerreceiveranddigisonde AT ooodeyemi daytimeequatorialspreadflikeirregularitiesdetectedbyhfdopplerreceiveranddigisonde AT aoadewale daytimeequatorialspreadflikeirregularitiesdetectedbyhfdopplerreceiveranddigisonde |