Statistics of 150-km echoes over Jicamarca based on low-power VHF observations
In this work we summarize the statistics of the so-called 150-km echoes obtained with a low-power VHF radar operation at the Jicamarca Radio Observatory (11.97 S, 76.87 W, and 1.3 dip angle at 150-km altitude) in Peru. Our results are based on almost four years of observations between August 200...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2006-07-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/24/1305/2006/angeo-24-1305-2006.pdf |
| _version_ | 1818061285755977728 |
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| author | J. L. Chau E. Kudeki |
| author_facet | J. L. Chau E. Kudeki |
| author_sort | J. L. Chau |
| collection | DOAJ |
| description | In this work we summarize the statistics of the so-called 150-km
echoes obtained with a low-power VHF radar operation at the Jicamarca
Radio Observatory (11.97 S, 76.87 W, and 1.3
dip angle at 150-km altitude) in Peru. Our results are based on almost
four years of observations between August 2001 and July 2005
(approximately 150 days per year). The majority of the observations
have been conducted between 08:00 and 17:00 LT. We present
the statistics of occurrence of the echoes for each of the four seasons as a
function of time of day and altitude. The occurrence frequency of the
echoes is ~75% around noon and start decreasing
after 15:00 LT and disappear after 17:00 LT in all seasons. As
shown in previous campaign observations, the 150-echoes appear at a
higher altitude (>150 km) in narrow layers in the morning, reaching lower
altitudes (~135 km) around noon, and disappear at higher
altitudes (>150 km) after 17:00 LT. We show that although
150-km echoes are observed all year long, they exhibit a
clear seasonal variability on altitudinal coverage and the percentage of
occurrence around noon and early in the morning. We also show
that there is a strong day-to-day variability, and no correlation
with magnetic activity. Although our results do not solve the
150-km riddle, they should be taken into account when a reasonable
theory is proposed. |
| first_indexed | 2024-12-10T13:45:53Z |
| format | Article |
| id | doaj.art-133113ec27e04c71aa753b552d17affe |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-10T13:45:53Z |
| publishDate | 2006-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-133113ec27e04c71aa753b552d17affe2022-12-22T01:46:26ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762006-07-01241305131010.5194/angeo-24-1305-2006Statistics of 150-km echoes over Jicamarca based on low-power VHF observationsJ. L. Chau0E. Kudeki1Radio Observatorio de Jicamarca, Instituto Geofísico del Perú, Lima, PeruDepartment of Electrical and Computer Engineering, University of Illinois, Urbana-Champaign, Illinois, USAIn this work we summarize the statistics of the so-called 150-km echoes obtained with a low-power VHF radar operation at the Jicamarca Radio Observatory (11.97 S, 76.87 W, and 1.3 dip angle at 150-km altitude) in Peru. Our results are based on almost four years of observations between August 2001 and July 2005 (approximately 150 days per year). The majority of the observations have been conducted between 08:00 and 17:00 LT. We present the statistics of occurrence of the echoes for each of the four seasons as a function of time of day and altitude. The occurrence frequency of the echoes is ~75% around noon and start decreasing after 15:00 LT and disappear after 17:00 LT in all seasons. As shown in previous campaign observations, the 150-echoes appear at a higher altitude (>150 km) in narrow layers in the morning, reaching lower altitudes (~135 km) around noon, and disappear at higher altitudes (>150 km) after 17:00 LT. We show that although 150-km echoes are observed all year long, they exhibit a clear seasonal variability on altitudinal coverage and the percentage of occurrence around noon and early in the morning. We also show that there is a strong day-to-day variability, and no correlation with magnetic activity. Although our results do not solve the 150-km riddle, they should be taken into account when a reasonable theory is proposed.https://www.ann-geophys.net/24/1305/2006/angeo-24-1305-2006.pdf |
| spellingShingle | J. L. Chau E. Kudeki Statistics of 150-km echoes over Jicamarca based on low-power VHF observations Annales Geophysicae |
| title | Statistics of 150-km echoes over Jicamarca based on low-power VHF observations |
| title_full | Statistics of 150-km echoes over Jicamarca based on low-power VHF observations |
| title_fullStr | Statistics of 150-km echoes over Jicamarca based on low-power VHF observations |
| title_full_unstemmed | Statistics of 150-km echoes over Jicamarca based on low-power VHF observations |
| title_short | Statistics of 150-km echoes over Jicamarca based on low-power VHF observations |
| title_sort | statistics of 150 km echoes over jicamarca based on low power vhf observations |
| url | https://www.ann-geophys.net/24/1305/2006/angeo-24-1305-2006.pdf |
| work_keys_str_mv | AT jlchau statisticsof150kmechoesoverjicamarcabasedonlowpowervhfobservations AT ekudeki statisticsof150kmechoesoverjicamarcabasedonlowpowervhfobservations |