Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles
We conducted a statistical study of polar mesospheric summer echoes (PMSEs) in relation to magnetic local time (MLT), considering the geomagnetic conditions using the K-index (or K). Additionally, we performed a case study to examine the velocity profile, specifically for high velocities (≥ ~100 m...
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| Format: | Article |
| Language: | English |
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The Korean Space Science Society
2023-09-01
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| Series: | Journal of Astronomy and Space Sciences |
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| Online Access: | https://www.janss.kr/archive/view_article?pid=jass-40-3-101 |
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| author | Young-Sook Lee Ram Singh Geonhwa Jee Young-Sil Kwak Yong Ha Kim |
| author_facet | Young-Sook Lee Ram Singh Geonhwa Jee Young-Sil Kwak Yong Ha Kim |
| author_sort | Young-Sook Lee |
| collection | DOAJ |
| description | We conducted a statistical study of polar mesospheric summer echoes (PMSEs) in relation to magnetic local time (MLT),
considering the geomagnetic conditions using the K-index (or K). Additionally, we performed a case study to examine the
velocity profile, specifically for high velocities (≥ ~100 m/s) varying with high temporal resolution at high K-index values. This
study utilized the PMSE data obtained from the mesosphere–stratosphere–troposphere radar located in Esrange, Sweden
(63.7°N, 21°E). The change in K-index in terms of MLT was high (K ≥ 4) from 23 to 04 MLT, estimated for the time PMSE was
present. During the near-midnight period (0–4 MLT), both PMSE occurrence and signal-to-noise ratio (SNR) displayed an
asymmetric structure with upper curves for K ≥ 3 and lower curves for K < 3. Furthermore, the occurrence of high velocities
peaked at 3–4 MLT for K ≥ 3. From case studies focusing on the 0–3 MLT period, we observed persistent eastward-biased high
velocities (≥ 200 m/s) prevailing for ~18 min. These high velocities were accompanied with the systematic motion of profiles
at 85–88 km, including large shear formation. Importantly, the rapid variations observed in velocity could not be attributed to
neutral wind effects. The present findings suggest a strong substorm influence on PMSE, especially in the midnight and early
dawn sectors. The large zonal drift observed in PMSE were potentially energized by local electromagnetic fields or the global
convection field induced by the electron precipitation during substorms. |
| first_indexed | 2024-03-08T06:33:01Z |
| format | Article |
| id | doaj.art-15be50b3f35548bbbce7e4add1aeac50 |
| institution | Directory Open Access Journal |
| issn | 2093-5587 2093-1409 |
| language | English |
| last_indexed | 2024-03-08T06:33:01Z |
| publishDate | 2023-09-01 |
| publisher | The Korean Space Science Society |
| record_format | Article |
| series | Journal of Astronomy and Space Sciences |
| spelling | doaj.art-15be50b3f35548bbbce7e4add1aeac502024-02-03T11:07:58ZengThe Korean Space Science SocietyJournal of Astronomy and Space Sciences2093-55872093-14092023-09-0140310111110.5140/JASS.2023.40.3.101Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height ProfilesYoung-Sook Lee0https://orcid.org/0000-0002-7746-9718Ram Singh1https://orcid.org/0000-0002-8140-3500Geonhwa Jee2https://orcid.org/0000-0001-7996-0482Young-Sil Kwak3https://orcid.org/0000-0003-3375-8574Yong Ha Kim4https://orcid.org/0000-0003-0200-9423Department of Astronomy and Space Science, Chungnam National University, Daejeon 34134, KoreaDepartment of Astronomy and Space Science, Chungnam National University, Daejeon 34134, KoreaKorea Polar Research Institute, Incheon 21990, KoreaKorea Astronomy and Space Science Institute, Daejeon 34055, KoreaChungnam National University, Daejeon 34134, KoreaWe conducted a statistical study of polar mesospheric summer echoes (PMSEs) in relation to magnetic local time (MLT), considering the geomagnetic conditions using the K-index (or K). Additionally, we performed a case study to examine the velocity profile, specifically for high velocities (≥ ~100 m/s) varying with high temporal resolution at high K-index values. This study utilized the PMSE data obtained from the mesosphere–stratosphere–troposphere radar located in Esrange, Sweden (63.7°N, 21°E). The change in K-index in terms of MLT was high (K ≥ 4) from 23 to 04 MLT, estimated for the time PMSE was present. During the near-midnight period (0–4 MLT), both PMSE occurrence and signal-to-noise ratio (SNR) displayed an asymmetric structure with upper curves for K ≥ 3 and lower curves for K < 3. Furthermore, the occurrence of high velocities peaked at 3–4 MLT for K ≥ 3. From case studies focusing on the 0–3 MLT period, we observed persistent eastward-biased high velocities (≥ 200 m/s) prevailing for ~18 min. These high velocities were accompanied with the systematic motion of profiles at 85–88 km, including large shear formation. Importantly, the rapid variations observed in velocity could not be attributed to neutral wind effects. The present findings suggest a strong substorm influence on PMSE, especially in the midnight and early dawn sectors. The large zonal drift observed in PMSE were potentially energized by local electromagnetic fields or the global convection field induced by the electron precipitation during substorms.https://www.janss.kr/archive/view_article?pid=jass-40-3-101polar mesospheric summer echo (pmse)substormsmagnetic local timezonal drift of polar mesospheric summer echoe (pmse)k-index |
| spellingShingle | Young-Sook Lee Ram Singh Geonhwa Jee Young-Sil Kwak Yong Ha Kim Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles Journal of Astronomy and Space Sciences polar mesospheric summer echo (pmse) substorms magnetic local time zonal drift of polar mesospheric summer echoe (pmse) k-index |
| title | Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles |
| title_full | Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles |
| title_fullStr | Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles |
| title_full_unstemmed | Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles |
| title_short | Polar Mesospheric Summer Echo Characteristics in Magnetic Local Time and Height Profiles |
| title_sort | polar mesospheric summer echo characteristics in magnetic local time and height profiles |
| topic | polar mesospheric summer echo (pmse) substorms magnetic local time zonal drift of polar mesospheric summer echoe (pmse) k-index |
| url | https://www.janss.kr/archive/view_article?pid=jass-40-3-101 |
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