Effect of the annular solar eclipse of 15 January 2010 on the low latitude mesosphere

Ratnam, M. Venkat; Eswaraiah, S.; Leena, P.P.; Patra, Amit; Murthy, B. V. Krishna; Rao, S. Vijaya Bhaskara

doi:10.1016/j.jastp.2012.02.022

Cited by 10 publications

(16 citation statements)

References 21 publications

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“…Chernogor [2010] for 1 August 2008 SE reported time delay of~6 min at 70-80 km altitude using VLF measurements at Kharkov (50°N; 36.23°E). Moreover, Ratnam et al [2012], for annular SE of 15 January 2010 observed time delay of~68 min at the altitude range of 60-80 km at a low latitude station, in India. The longer delay times (~1-2 h) have also been reported by various workers at E to F region ionosphere heights [Zhang et al, 2010;Yadav et al, 2013].…”

Section: Eclipse Day Wave-like Signaturesmentioning

confidence: 93%

“…Singh et al [1989] with multi-station study of total SE of 16 February 1980 over Indian region suggested that the receiving station should be more than 500 km from the totality path in order to detect any GWs associated effect with SE. However, Ratnam et al [2012] for the annular SE of 15 January 2010 observed GW signatures with periods~30-60 min at the station located at a distance of~350 km from the totality path. Most of the previous studies [Chimonas and Hines, 1970 Kumar et al [2013] for 22 July 2009 total solar eclipse over Indian sector using the GPS TEC data has shown the presence of WLS at totality station Varanasi (100% totality) with period~20-60 min and at partially eclipsed stations: Kanpur (95% totality) with period 80-90 min, Hyderabad (82% totality) with period~70-100 min and Bangalore (65% totality) with period 100-120 min.…”

Section: Eclipse Day Wave-like Signaturesmentioning

confidence: 96%

“…The passage of solar terminator is another main in situ source of GWs. Several studies have shown wave-like signatures (WLS)/GWs in E and F regions of ionosphere during SEs using Ionosonde and GPS total electron content (TEC) measurements [Liu et al, 1998;Altadill et al, 2001;Zerefos et al, 2007;Kumar et al, 2013;Yadav et al, 2013], but very few studies have attempted WLS/GWs in the Mesosphere/D region ionosphere [Bošková and Laštovička, 2001;Chernogor, 2010;Ratnam et al, 2012]. The probing of D region ionosphere is difficult as its altitude is too low for satellites and too high for balloons and due to low electron MAURYA ET AL.…”

Section: Introductionmentioning

confidence: 99%

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Low‐mid latitude D region ionospheric perturbations associated with 22 July 2009 total solar eclipse: Wave‐like signatures inferred from VLF observations

Maurya¹,

Phanikumar

Singh³

et al. 2014

JGR Space Physics

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We present first report on the periodic wave-like signatures (WLS) in the D region ionosphere during 22 July 2009 total solar eclipse using JJI, Japan, very low frequency (VLF) navigational transmitter signal (22.2 kHz) observations at stations, Allahabad, Varanasi and Nainital in Indian Sector, Busan in Korea, and Suva in Fiji. The signal amplitude increased on 22 July by about 6 and 7 dB at Allahabad and Varanasi and decreased by about 2.7, 3.5, and 0.5 dB at Nainital, Busan, and Suva, respectively, as compared to 24 July 2009 (normal day). The increase/decrease in the amplitude can be understood in terms of modal interference at the sites of modes converted at the discontinuity created by the eclipse intercepting the different transmitter-receiver great circle paths. The wavelet analysis shows the presence of WLS of period~16-40 min at stations under total eclipse and of period~30-80 min at stations under partial eclipse (~85-54% totality) with delay times between~50 and 100 min at different stations. The intensity of WLS was maximum for paths in the partially eclipsed region and minimum in the fully eclipsed region. The features of WLS on eclipse day seem almost similar to WLS observed in the nighttime of normal days (e.g., 24 July 2009). The WLS could be generated by sudden cutoff of the photo-ionization creating nighttime like conditions in the D region ionosphere and solar eclipse induced gravity waves coming to ionosphere from below and above. The present observations shed additional light on the current understanding of gravity waves induced D region ionospheric perturbations.

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Section: Eclipse Day Wave-like Signaturesmentioning

confidence: 93%

Section: Eclipse Day Wave-like Signaturesmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Low‐mid latitude D region ionospheric perturbations associated with 22 July 2009 total solar eclipse: Wave‐like signatures inferred from VLF observations

Maurya¹,

Phanikumar

Singh³

et al. 2014

JGR Space Physics

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“…where F is solar flux and χ is solar zenith angle which during eclipse day decreases to where γ is obscuration rate of Sun during the eclipse event [Ratnam et al, 2012]. The average electron density decrease of 26, 33, and 17 percentages is estimated for July, November, and May SEs (Table 1) for which solar obscurations were 45, 55, and 31 percentages, respectively.…”

Section: Region Changes Associated With Sementioning

confidence: 99%

Changes in the D region associated with three recent solar eclipses in the South Pacific region

Kumar

Maurya

et al. 2016

JGR Space Physics

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We estimate D region changes due to 22 July 2009 total solar eclipse (SE), 13–14 November 2012 total SE, and 9–10 May 2013 annular SE, using VLF navigational transmitters signal observations at Suva, Fiji. The North West Cape (NWC) signal (19.8 kHz) showed an amplitude and phase decrease of 0.70 dB and 23° during November SE and 2.0 dB and 90° during May SE. The modeling using Long Wave Propagation Capability code for NWC‐Suva path during November and May SEs showed an increase in average D region reflection height (H′) and sharpness factor (β) by 0.6 and 0.5 km and 0.012 and 0.015 km−1, respectively. The July total SE for JJI‐Suva path showed an increase in H′ of 1.5 km and a decrease in β of 0.055 km−1. The decrease in the electron density calculated using SE time H′ and β is maximum for July total SE and minimum for May annular SE. The effective recombination coefficient estimated from the decay and recovery of signal phase associated with May annular SE was higher (27%) than normal daytime value 5.0 × 10−7 cm−3 s−1 and varied between 1.47 × 10−6 and 1.15 × 10−7 cm−3 s−1 in the altitude 70 to 80 km. Morlet wavelet analysis of signals amplitude shows strong wave‐like signatures (WLS) associated with three SEs with period ranging 24–66 min, but the intensity and duration of WLS show no clear dependence on SE magnitude and type. Apart from the cooling spot, the eclipse shadow can also generate WLS associated with atmospheric gravity waves.

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“…Due to their complex influence on the Earth's ionosphere and atmosphere, solar eclipses are of interest to geophysicists, radio scientists, etc. Eclipse effects arising in the ionosphere have been studied for more than 60 years, with a great deal of the research devoted to various radio propagation aspects of this phenomenon and extensively published in the literature [ Crary and Schneible , ; Kaufmann and Schaal , ; Lynn , ; Maurya et al ., ; Venkat Ratnam et al ., ; Cheng et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Effect of the total solar eclipse of 20 March 2015 on the ELF propagation over high‐latitude paths

Tereshchenko

Sidorenko

Tereshchenko

et al. 2015

Geophysical Research Letters

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Propagation of the artificial electromagnetic waves with frequency of 82 Hz in the Earth‐ionosphere waveguide was observed during the solar eclipse on both partially and totally obscured high‐latitude paths with a length of 450–1200 km. Field excitation was monitored by the reference measurements in the near zone of the transmitter, which are free of the ionospheric influence. It is found that the amplitude of the field at the remote points varied depending on the solar illumination and solar elevation angle. We suppose that this effect was probably caused by the increase in the effective height of the ionospheric D layer, just as it was previously observed in VLF. The obtained results demonstrate the response of the propagating extremely low frequency (ELF, 3–300 Hz) wave to the change in the ionospheric boundary. This effect has been for the first time observed in this frequency range during a total solar eclipse.

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Effect of the annular solar eclipse of 15 January 2010 on the low latitude mesosphere

Cited by 10 publications

References 21 publications

Low‐mid latitude D region ionospheric perturbations associated with 22 July 2009 total solar eclipse: Wave‐like signatures inferred from VLF observations

Low‐mid latitude D region ionospheric perturbations associated with 22 July 2009 total solar eclipse: Wave‐like signatures inferred from VLF observations

Changes in the D region associated with three recent solar eclipses in the South Pacific region

Effect of the total solar eclipse of 20 March 2015 on the ELF propagation over high‐latitude paths

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