Journal ArticleDOI
Nighttime-like quasi periodic echoes induced by a partial solar eclipse
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TLDR
In this paper, the first observations of solar eclipse induced mid-latitude plasma irregularities using the middle and upper atmosphere radar (MU radar) at Shigaraki (34.85°N,136.1°E, 25.0°N geomagnetic) were presented.Abstract:
[1] The first observations of solar eclipse induced mid-latitude plasma irregularities using the middle and upper atmosphere radar (MU radar) at Shigaraki (34.85°N,136.1°E, 25.0°N geomagnetic) are presented. The observations were done during the partial solar eclipse on 22 July, 2009. The observations show that the sudden withdrawal of solar radiation could deplete the background E-region densities, thereby unmasking the long-lived metallic ions within the strong and patchy Sporadic E-layers. As a result of this, Quasi-Periodic (QP) echoes were generated, which were detected by the MU radar. These echoes resemble the normal post-sunset QP echoes observed over mid-latitudes as revealed by the multi-channel interfereometry imaging. This example shows that over mid-latitudes E-region plasma irregularities can be generated during a partial solar eclipse, revealing a hitherto unobserved aspect of mid-latitude ionospheric responses to eclipses.read more
Citations
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Journal ArticleDOI
Plasma flux and gravity waves in the midlatitude ionosphere during the solar eclipse of 20 May 2012
Gang Chen,Gang Chen,Chen Wu,Xueqin Huang,Zhengyu Zhao,Dingkun Zhong,Hao Qi,Liang Huang,Lei Qiao,Jin Wang +9 more
TL;DR: In this paper, five ionosondes in the Northeast Asia were used to record the midlatitude ionospheric responses to the solar eclipse of 20 May 2012, and the latitude dependence of the eclipse lag was studied first.
Journal ArticleDOI
Gravity waves and spread Es observed during the solar eclipse of 22 July 2009
Gang Chen,Zhengyu Zhao,Yuannong Zhang,Guobin Yang,Chen Zhou,Shuo Huang,Ting Li,Ning Li,Hengqing Sun +8 more
TL;DR: In this paper, two ground-based high-frequency radio systems were applied to observe the ionospheric variations over Wuhan, China during the total solar eclipse of 22 July 2009.
Journal ArticleDOI
Daytime E region field‐aligned irregularities observed during a solar eclipse
TL;DR: In this article, a high-frequency coherent scatter radar was used to detect the E region irregularities and the unique feature of the observations is the synchronized oscillations in the irregularities and in the Es layer, which will help address the outstanding question of the source of the midlatitude E region FAIs.
Journal ArticleDOI
Multilayered Sporadic E Response to the Annular Solar Eclipse on June 21, 2020
Jin Wang,Xiaomin Zuo,Yang-Yi Sun,Tao Yu,Yungang Wang,Lihui Qiu,Tian Mao,Xiangxiang Yan,Na Yang,Yifan Qi,Jiuhou Lei,Lingfeng Sun,Biqiang Zhao +12 more
Journal ArticleDOI
Response of the mid-latitude D-region ionosphere to the total solar eclipse of 22 July 2009 studied using VLF signals in South Korean peninsula
TL;DR: In this paper, the authors analyzed VLF signals received at Busan to study the D-region changes linked with the solar eclipse event of 22 July 2009 for very short (� 390 km) transmitter-receiver great circle path (TRGCP) during local noon time 00:36-03:13 UT (09:36 -12:13 KST).
References
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Journal ArticleDOI
International Reference Ionosphere 2007: Improvements and new parameters
TL;DR: The International Reference Ionosphere (IRI) is the de facto international standard for the climatological specification of ionospheric parameters and as such it is currently undergoing registration as Technical Specification (TS) of the International Standardization Organization (ISO) as discussed by the authors.
Journal ArticleDOI
Recent work on mid-latitude and equatorial sporadic-E
TL;DR: In this article, it was shown that sporadic-E is most likely due to a vertical shear in the horizontal east-west wind and this theory accounts for the detailed observations of the wind and electron density profiles.
Journal ArticleDOI
Mid-latitude E region field-aligned irregularities observed with the MU radar
Mamoru Yamamoto,Shoichiro Fukao,Ronald F. Woodman,Tadahiko Ogawa,Toshitaka Tsuda,Susumu Kato +5 more
Abstract: Fine structures E region field-aligned irregularities were observed on June 24–25, 1989, with the MU radar at Shigaraki, Japan (34.9°N, 136.1°E; geomagnetic latitude 25.0°N). The 3.2-m scale irregularities were observed with the MU radar in five main beam directions, each of which was nearly perpendicular to the geomagnetic field at 100 km altitude. Doppler spectra were obtained every 20 s with a range resolution of 600 m. Field-perpendicular echoes appeared from 2130 to 2330 LT and from 0400 to 1100 LT, times that correspond to postsunset and postsunrise period in the E region. A preliminary examination of the Doppler spectra indicates spectral widths of 50–120 m s−1 and the mean Doppler velocities are well below the ion acoustic speed. These spectral characteristics are consistent with those obtained in the equatorial and auroral electrojets, and have been attributed to the gradient drift instability. The echoes observed during the postsunset and postsunrise periods showed quite different morphologies in the time-height distribution. For this reason, they are classified into two types, ‘continuous’ and ‘quasi-periodic.’ The appearance of the ‘continuous’ echoes was mainly continuous in time and situated between 90 and 100 km altitude during the postsunrise period. The appearance of the ‘quasi-periodic’ echoes was intermittent with periods of 5–10 min and situated above 100 km altitude during the postsunset period. The quasi-periodic echoes showed phase propagation toward the radar, while the averaged mean Doppler velocity was away from the radar. By measuring the time delays in echo regions from five directions, an apparent westward motion (approximately 120 m s−1) of the irregularity regions was estimated.
Journal ArticleDOI
Atmospheric gravity waves induced by a solar eclipse, 2
G. Chimonas,Colin O. Hines +1 more
Journal ArticleDOI
Gravity wave modulation of gradient drift instabilities in mid-latitude sporadic E irregularities
TL;DR: In this article, the conditions of local gradient drift instability are not sufficient and one has to consider the integrated properties of each magnetic filed tube, which can be explained in terms of gravity waves with frequencies close to the Brunt-Vaisala frequency.