Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea
We present preliminary observations of the field-aligned-irregularities (FAIs) in the E and F regions during the solar minimum (2009 - 2010) using the 40.8 MHz coherent backscatter radar at Daejeon (36.18°N, 127.14°E, 26.7°N dip latitude) in South Korea. The radar, which consists of 24 Yagi antenn...
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| Format: | Article |
| Language: | English |
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The Korean Space Science Society
2014-03-01
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| Series: | Journal of Astronomy and Space Sciences |
| Subjects: | |
| Online Access: | http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2014/v31n1/OJOOBS_2014_v31n1_15.pdf |
| _version_ | 1827362882821554176 |
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| author | Young-Sil Kwak Tae-Yong Yang Hoysub Kil Devulapalli Venkata Phanikumar Bok-Haeng Heo Jae-Jin Lee Junga Hwang Seong-Hwan Choi Young-Deuk Park Ho-Seong Choi |
| author_facet | Young-Sil Kwak Tae-Yong Yang Hoysub Kil Devulapalli Venkata Phanikumar Bok-Haeng Heo Jae-Jin Lee Junga Hwang Seong-Hwan Choi Young-Deuk Park Ho-Seong Choi |
| author_sort | Young-Sil Kwak |
| collection | DOAJ |
| description | We present preliminary observations of the field-aligned-irregularities (FAIs) in the E and F regions during the solar
minimum (2009 - 2010) using the 40.8 MHz coherent backscatter radar at Daejeon (36.18°N, 127.14°E, 26.7°N dip latitude)
in South Korea. The radar, which consists of 24 Yagi antennas, observes the FAIs using a single beam with a peak power of
24 kW. The radar has been continuously operated since December 2009. Depending on the manner of occurrence of the
backscatter echoes, the E-region echoes are largely divided into two types: quasi-periodic (QP) and continuous echoes.
Our observations show that the QP echoes occur frequently above an altitude of 105 km in the post-sunset period and
continuous echoes occur preferentially around an altitude of 105 km in the post-sunrise period. QP echoes appear as
striated discrete echoes for a period of about 10 - 20 min. The QP-type echoes occur more frequently than the continuoustype
echoes do and the echo intensity of the QP type is stronger than that of the continuous type. In the F region, the FAIs
occur at night at an altitude interval of 250 - 450 km. As time proceeds, the occurrence height of the FAIs gradually increases
until early in the morning and then decreases. The duration of the F-region FAIs is typically a few hours at night, although,
in rare cases, FAIs persist throughout the night or appear even after sunrise. We discuss the similarities and differences of
the FAIs observed by the Daejeon radar in comparison with other radar observations. |
| first_indexed | 2024-03-08T07:36:54Z |
| format | Article |
| id | doaj.art-27c48540d9b4423ab79f5bee347f8cc8 |
| institution | Directory Open Access Journal |
| issn | 2093-5587 2093-1409 |
| language | English |
| last_indexed | 2024-03-08T07:36:54Z |
| publishDate | 2014-03-01 |
| publisher | The Korean Space Science Society |
| record_format | Article |
| series | Journal of Astronomy and Space Sciences |
| spelling | doaj.art-27c48540d9b4423ab79f5bee347f8cc82024-02-02T18:29:15ZengThe Korean Space Science SocietyJournal of Astronomy and Space Sciences2093-55872093-14092014-03-01311152310.5140/JASS.2014.31.1.15Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South KoreaYoung-Sil Kwak0Tae-Yong Yang1Hoysub Kil2Devulapalli Venkata Phanikumar3Bok-Haeng Heo4Jae-Jin Lee5Junga Hwang6Seong-Hwan Choi7Young-Deuk Park8Ho-Seong Choi9Division of Space Science, Korea Astronomy and Space Science Institute, Daejeon 305-348, KoreaDivision of Space Science, Korea Astronomy and Space Science Institute, Daejeon 305-348, KoreaSpace Department, The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USAAryabhatta Research Institute of Observational Sciences (ARIES), Nainital, IndiaKorea Meteorological Administration, Seoul 156-720, KoreaDivision of Space Science, Korea Astronomy and Space Science Institute, Daejeon 305-348, KoreaDivision of Space Science, Korea Astronomy and Space Science Institute, Daejeon 305-348, KoreaDivision of Space Science, Korea Astronomy and Space Science Institute, Daejeon 305-348, KoreaDivision of Space Science, Korea Astronomy and Space Science Institute, Daejeon 305-348, KoreaRepublic of Korea Air Force, Gyeryong-si, KoreaWe present preliminary observations of the field-aligned-irregularities (FAIs) in the E and F regions during the solar minimum (2009 - 2010) using the 40.8 MHz coherent backscatter radar at Daejeon (36.18°N, 127.14°E, 26.7°N dip latitude) in South Korea. The radar, which consists of 24 Yagi antennas, observes the FAIs using a single beam with a peak power of 24 kW. The radar has been continuously operated since December 2009. Depending on the manner of occurrence of the backscatter echoes, the E-region echoes are largely divided into two types: quasi-periodic (QP) and continuous echoes. Our observations show that the QP echoes occur frequently above an altitude of 105 km in the post-sunset period and continuous echoes occur preferentially around an altitude of 105 km in the post-sunrise period. QP echoes appear as striated discrete echoes for a period of about 10 - 20 min. The QP-type echoes occur more frequently than the continuoustype echoes do and the echo intensity of the QP type is stronger than that of the continuous type. In the F region, the FAIs occur at night at an altitude interval of 250 - 450 km. As time proceeds, the occurrence height of the FAIs gradually increases until early in the morning and then decreases. The duration of the F-region FAIs is typically a few hours at night, although, in rare cases, FAIs persist throughout the night or appear even after sunrise. We discuss the similarities and differences of the FAIs observed by the Daejeon radar in comparison with other radar observations.http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2014/v31n1/OJOOBS_2014_v31n1_15.pdfVHF coherent backscatter radarionospheric irregularitiesmid-latitude |
| spellingShingle | Young-Sil Kwak Tae-Yong Yang Hoysub Kil Devulapalli Venkata Phanikumar Bok-Haeng Heo Jae-Jin Lee Junga Hwang Seong-Hwan Choi Young-Deuk Park Ho-Seong Choi Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea Journal of Astronomy and Space Sciences VHF coherent backscatter radar ionospheric irregularities mid-latitude |
| title | Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea |
| title_full | Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea |
| title_fullStr | Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea |
| title_full_unstemmed | Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea |
| title_short | Characteristics of the E - and F -region field-aligned irregularities in middle latitudes: Initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea |
| title_sort | characteristics of the e and f region field aligned irregularities in middle latitudes initial results obtained from the daejeon 40 8 mhz vhf radar in south korea |
| topic | VHF coherent backscatter radar ionospheric irregularities mid-latitude |
| url | http://ocean.kisti.re.kr/downfile/volume/kosss/OJOOBS/2014/v31n1/OJOOBS_2014_v31n1_15.pdf |
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