Possible effects of the total solar eclipse of August 11, 1999 on the geomagnetic field variations over Elaziǧ-Turkey

Özcan, Osman; Aydoǧdu, Mehmet

doi:10.1016/j.jastp.2004.03.009

Cited by 24 publications

(15 citation statements)

References 14 publications

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“…Recent observations show clear impacts of solar eclipse on geomagnetic field components at ground level [e.g., Nevanlinna and Häkkinen , 1991; Ozcan and Aydogdu , 2004; Strestik , 2001]. Although of these observations, the impact on the geomagnetic field components during eclipse is still confusing.…”

Section: Introductionmentioning

confidence: 99%

“…Although of these observations, the impact on the geomagnetic field components during eclipse is still confusing. For example, Ozcan and Aydogdu [2004] observed the 11 August 1999 total solar eclipse over Turkey and found a reduction of 20–40% in the ionospheric electron density, significant decrease in the eastward component (Y) of geomagnetic field, and no effect in the north–south component (X) of geomagnetic field. They suggested that the reduction in ionospheric electron density during the solar eclipse causes a modification of the geomagnetic field at ground level [ Ozcan and Aydogdu , 2004].…”

Section: Introductionmentioning

confidence: 99%

“…For example, Ozcan and Aydogdu [2004] observed the 11 August 1999 total solar eclipse over Turkey and found a reduction of 20–40% in the ionospheric electron density, significant decrease in the eastward component (Y) of geomagnetic field, and no effect in the north–south component (X) of geomagnetic field. They suggested that the reduction in ionospheric electron density during the solar eclipse causes a modification of the geomagnetic field at ground level [ Ozcan and Aydogdu , 2004]. Strestik [2001] observed pronounced decrease in north–south component of geomagnetic field (X), pronounced increase in the east–west component (Y), and an increase in the up‐down component (Z).…”

Section: Introductionmentioning

confidence: 99%

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Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

2010

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[1] The ionospheric and geomagnetic response to the total eclipse of the Sun on 1 August 2008 over Northern Hemisphere has been examined using 14 GPS, three ISR radar, and three magnetometer ground-based stations. Three different approaches were employed to examine the TEC depletion occurrence at the GPS stations: determination of the TEC depletion parameters during the solar eclipse with respect the quiet day TEC variations, comparison of the total TEC (STEC) during the solar eclipse period with respect to quiet day TEC measurements for the same period of time, and determination of the average daily TEC obtained from eight GPS stations and compares the values with the average quiet day TEC at these stations. The GPS observations indicate obvious TEC depression occurrence at all stations with the values was varying between 11% and 40%. The observations show that TEC depression at most GPS stations started on the neck of the first contact of the eclipse followed by deeper negative deviation while the area of optical disk obscured getting larger. Periods of TEC depletion were also observed before the first contact time of solar eclipse and after the fourth contact of solar eclipse due to earlier and later obscuration of the solar corona before and after the eclipse observation time. The incoherent scatter radar observations at Svalbard, Tromso, and Sondrestrom also show clear depletion occurrence in electron density, electron temperature, ion velocity, and plasma cutoff frequency during the solar eclipse passage at these stations. Radar measurements show obvious difference in the ionospheric response between the E and F layers of ionosphere and between ion and electron temperature in the F layer. The geomagnetic field response to the solar eclipse at CBB, RESO, and NUR stations was examined by using two different techniques, first by comparing the daily variations of geomagnetic field during the eclipse period with the variations on the day before and day after the eclipse, and second by determination the D magnetic field with respect to the average quiet geomagnetic field. The results show obvious decrease in the total field, X and Z components of geomagnetic field and obvious increase in the Y component at both CBB and RESO stations. The depletion in X, Z, and total field was in the range between 15 and 28 nT while the increase in the Y component was 18-22 nT.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

2010

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“…where α can be used individually for electrons and ions, or for each alone να is collision frequency for electrons and ions and m is mass. vα is particle velocity [1,4]. Then, by making the assumptions made by Özcan and Aydoğdu 2004 and by updating expressions for coordinates (01.22 N, 103.55 E), the following expressions were obtained.…”

Section: Methodsmentioning

confidence: 99%

Possible Effect of Stratospheric QBO on The Ionospheric E-Region Current Densities

Sağır¹,

Özcan²

2018

Muş Alparslan Üniversitesi Fen Bilimleri Dergisi

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It is known that ionospheric winds cause the ions to drift in the geomagnetic field. This drift set up a current which produces ground-level geomagnetic field variations. In this study, the relationship between stratospheric QBO and the ionospheric E-region current densities (Jx and Jy) for low latitudes (01.22 N, 103.55 E) have been statistically investigated using the multiple regression model. Also the effect of F10.7 solar flux index was included in the investigation. As a result of the investigation using the multiple regression model, it was determine that an increase/a decrease of 1 s.f.u in the F10.7 solar flux caused an increase/a decrease of 1.5x10-2 A/km and 2.5x10-2 A/km on Jx and Jy current density, respectively. On the other hand, an increase/ a decrease of 1 m / s in the QBO caused a decrease/ an increase of 3x10-3 A/km and 4x10-3 A/km on Jx and Jy current densities, respectively.

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“…For the magnetic field disturbance caused by solar eclipse, Chapman discussed the possibility from theoretical angle, Kato and Bomke verified the effect at low latitudes [19] . Ozcan [22] discovered that during the August 11th, 1999 total solar eclipse there was no significant effect on the north-south component of the magnetic field, but the westward component decreased. Abidin [1] observed that during the November 23rd, 2003 total solar eclipse a severe magnetic storm took place two days before the solar eclipse, but at the same time with the eclipse there were TID (Traveling Ionospheric Disturbances) events.…”

Section: Tec Calculation Using Igs Stationsmentioning

confidence: 99%

Ionospheric Behavior During the Solar Eclipse of 22 July 2009 and Its Effect on Positioning

Wang

Dongchen

et al. 2010

Chinese J of Geophysics

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On Jul. 22nd, 2009, an exceptionally long total solar eclipse was visible within a narrow corridor that traversed the Eastern Hemisphere. A medium geomagnetic storm synchronized with solar eclipse and led to the complexity of the ionospheric variations. This work is to analyze the ionospheric behavior during this event and its effect on positioning. The used GPS data were collected by the Chongqing CORS, Wuhan CORS, IGS stations such as WUHN and SHAO in Moon's umbra, and other IGS stations in Moon's penumbra. By comparing the TEC variations of 3 consecutive days, and using high-sampling rate CORS data, we study instantaneous changes of the total electron content (TEC) during the event. The result shows that TEC declined by (1∼4)TECU at places depending on different locations and times. Meanwhile, in real time point positioning, horizontal accuracy didn't have remarkable changes, but vertical accuracy declined up to several meters. And in real time baseline positioning, horizontal accuracy still reached centimeter level, and vertical accuracy remained at decimeter level in the early stage of solar eclipse. But the geomagnetic storm occurred in the latter stage of solar eclipse that led to the decline of horizontal accuracy to decimeter, and vertical accuracy to meter level.

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Possible effects of the total solar eclipse of August 11, 1999 on the geomagnetic field variations over Elaziǧ-Turkey

Cited by 24 publications

References 14 publications

Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

Ionospheric and geomagnetic response to the total solar eclipse on 1 August 2008 over Northern Hemisphere

Possible Effect of Stratospheric QBO on The Ionospheric E-Region Current Densities

Ionospheric Behavior During the Solar Eclipse of 22 July 2009 and Its Effect on Positioning

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