Wavelet characterisation of ionospheric acoustic and gravity waves occurring during the solar eclipse of August 11, 1999

Šauli, P.; Abry, Patrice; Boška, J.; Duchayne, L.

doi:10.1016/j.jastp.2005.03.024

Cited by 58 publications

(64 citation statements)

References 21 publications

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“…The main aim of this study is to explore whether the wave-like signatures (WLS) were induced in the D region ionosphere by 22 July 2009 total SE for which we have applied Morlet wavelet technique [Grossmann and Morlet, 1984;Sauli et al, 2006] for the normal day ( Figure 3) and eclipse day ( Figure 4, section, 3.3) JJI amplitude data. The wavelet transform of the signal X(u, z) is defined as [Sauli et al, 2006]:…”

Section: Normal Day Wave-like Signaturesmentioning

confidence: 99%

“…The TIDs are very unlikely to be the possible sources of WLS presented here as 22 July 2009 storm was a moderate geomagnetic storm. Sauli et al [2006] for SE of 11 August 1999 using the electron density data recorded with classical ionosonde IPS 42 KEL Aerospace suggested the gravity and Journal of Geophysical Research: Space Physics 10.1002/2013JA019521 acoustic waves as possible sources of ED variations located in two regions. First region is located at 200 km which is the transition height between F1 and F2 regions where difference in solar radiation flux creates gradients of temperature, pressure, electron, and ion concentration.…”

Section: 1002/2013ja019521mentioning

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: Normal Day Wave-like Signaturesmentioning

confidence: 99%

Section: 1002/2013ja019521mentioning

confidence: 99%

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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“…ionospheric plasma recombination rates), the interest shifted in recent years towards investigating the atmospheric gravity wave (AGW) phenomena generated by the Moon's shadow passing (at a supersonic speed) through the atmosphere (Chimonas & Hines 1970;Altadill et al 2001;Davis et al 2001;Sauli et al 2006Sauli et al , 2007Jakowski et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Multi-instrument observations of the solar eclipse on 20 March 2015 and its effects on the ionosphere over Belgium and Europe

Stankov

Bergeot

Berghmans

et al. 2017

J. Space Weather Space Clim.

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A total solar eclipse occurred on 20 March 2015, with a totality path passing mostly above the North Atlantic Ocean, which resulted in a partial solar eclipse over Belgium and large parts of Europe. In anticipation of this event, a dedicated observational campaign was set up at the Belgian Solar-Terrestrial Centre of Excellence (STCE). The objective was to perform high-quality observations of the eclipse and the associated effects on the geospace environment by utilising the advanced space-and ground-based instrumentation available to the STCE in order to further our understanding of these effects, particularly on the ionosphere. The study highlights the crucial importance of taking into account the eclipse geometry when analysing the ionospheric behaviour during eclipses and interpreting the eclipse effects. A detailed review of the eclipse geometry proves that considering the actual obscuration level and solar zenith angle at ionospheric heights is much more important for the analysis than at the commonly referenced Earth's surface or at the plasmaspheric heights. The eclipse occurred during the recovery phase of a strong geomagnetic storm which certainly had an impact on (some of) the ionospheric characteristics and perhaps caused the omission of some ''low-profile'' effects. However, the analysis of the ionosonde measurements, carried out at unprecedented high rates during the eclipse, suggests the occurrence of travelling ionospheric disturbances (TIDs). Also, the high temporal and spatial resolution measurements proved very important in revealing and estimating some finer details of the delay in the ionospheric reaction and the ionospheric disturbances.

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“…(Abram et al, 2000) Solar eclipse phenomenon has attracted researchers from various fields. Many researchers investigated the incidents related to the meteorological parameters (e.g., temperature, Nishanth et al, 2011) wind speed, (Nishanth et al, 2011) gravity, (Altadill et al, 2001;Šauli et al, 2006) humidity, (Nishanth et al, 2011) geomagnetic field, (Özcan et al, 2004) ionospheric electron content, (Liu et al, 1999) and light irradiation Zerefos et al, 2001;Nishanth et al, 2011;Libra et al, 2016)) and the photochemical properties in the atmosphere (Hunt 1965;Bojkov 1968;Eastman et al, 1980;Abram et al, 2000;Chudzyński et al, 2001;Tzanis et al, 2008;Sharma et al, 2010;Nishanth et al, 2011). However, no research investigates on the impact of solar eclipse to the photodecomposition of organic material in the Earth.…”

Section: Introductionmentioning

confidence: 99%

Photodecomposition Profile of Organic Material during the Partial Solar Eclipse of 9 March 2016 and Its Correlation with Organic Material Concentration and Photocatalyst Amount

Nandiyanto

Sofiani

Permatasari

et al. 2016

IJOST

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The present study investigated the photodecomposition of an organic material during the partial (88.76%) solar eclipse phenomenon of 9 March 2016 in Bandung, Indonesia. Curcumin and anatase titanium dioxide (TiO 2 ) particles were used as models of organic material and photocatalyst, respectively. The influence of the process parameters (i.e., curcumin concentration and the amount of TiO 2 ) on the photodecomposition process was also investigated. The results showed that the curcumin was decomposed along with the solar light irradiation time. During the solar eclipse, the photodecomposition rate is suddenly down. The partial solar eclipse provided a slower photodecomposition process than the process under sunny days (conducted on 8 and 10 March 2016). The concentration of curcumin and the amount of TiO 2 also have played an important role in the photodecomposition, in which the lower concentration of curcumin and the higher amount of TiO 2 have a correlation to the obtainment of higher photodecomposition rate.

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Wavelet characterisation of ionospheric acoustic and gravity waves occurring during the solar eclipse of August 11, 1999

Cited by 58 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

Multi-instrument observations of the solar eclipse on 20 March 2015 and its effects on the ionosphere over Belgium and Europe

Photodecomposition Profile of Organic Material during the Partial Solar Eclipse of 9 March 2016 and Its Correlation with Organic Material Concentration and Photocatalyst Amount

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