Day-to-Day Variability of H and Z Components of the Geomagnetic Field at the African Longitudes

Obiekezie, T. N.; Obiadazie, S. C.; Agbo, G. A.

doi:10.1155/2013/909258

Cited by 15 publications

(10 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(1965) and Torta et al (1997), studied the variability of the Sq. More recently, in Africa, Middle East and Asia, Rabiu et al (2009); Obiekezie & Obiadazie (2013); Bolaji & al. (2013); Abbas et al (2013) and Pham et al (2011), characterized the Sq current system.…”

Section: Introductionmentioning

confidence: 99%

Sq solar variation at Medea Observatory (Algeria), from 2008 to 2011

Anad

Amory‐Mazaudier

Hamoudi

et al. 2016

Advances in Space Research

View full text Add to dashboard Cite

International audienceThis paper presents the regular variations of terrestrial magnetic field recorded by a new magnetic observatory Medea, Algeria (geographic latitude: 36.85 • N, geographic longitude: 2.93 • E, geomagnetic latitude: 27.98 • N, geomagnetic longitude: 77.7 • E) during 2008-2011. The diurnal and seasonal variations of the solar quiet (Sq) variations are analyzed. The results show differences in the diurnal pattern of the northward-component Sq variation (SqX) at different seasons. The seasonal variation of SqX is similar in different years. The diurnal pattern of SqX from July through September cannot be explained by an equivalent current system that is symmetric about the noon time sector. The observations indicate that the major axis of the elliptic current system is tilted towards the equator in the morning hours during those months. The diurnal pattern of SqY indicates southward currents in the morning and northward currents in the afternoon, except during February-March 2009 when there is apparently no southward current during the morning. For the other months, the observations indicate that the maximum northward current intensity in the afternoon tends to be greater than the maximum southward current intensity in the morning. This is because of the UT variation of the Sq current system. That is, the pattern and strength of the Sq current system are different when SqY is measured in the morning around 8 UT and in the afternoon around 14 UT. The amplitude of these extreme varies linearly with the solar cycle. For the SqY component, the changes in the morning maximum have an annual variation while that of the afternoon minimum has a semi-annual variation. These variations are attributed to seasonal variations in the ionospheric E-region conductivity and atmospheric tidal winds. The field-aligned currents can also contribute to the seasonal variation of SqY. However, the two-dimensional approach used in this article does not allow us to quantitatively determine their influences

show abstract

Section: Introductionmentioning

confidence: 99%

Sq solar variation at Medea Observatory (Algeria), from 2008 to 2011

Anad

Amory‐Mazaudier

Hamoudi

et al. 2016

Advances in Space Research

View full text Add to dashboard Cite

show abstract

“…The S q has also a relationship with crustal and upper mantle electromagnetic properties, and the underground conductivity and (or) permeability can change its shape and magnitude. Obviously, the formation of a local current system depends primarily on any regional conductivity anomaly, and the greater part of the current induced by this anomaly will be distributed in the deep mantle, with a small part in the ocean (Rikitake, , ; Obiekezie et al, ).…”

Section: Discussionmentioning

confidence: 99%

Anomalous phenomena in DC–ULF geomagnetic daily variation registered three days before the 12 May 2008 Wenchuan MS 8.0 earthquake

Wang

et al. 2019

Earth and Planetary Physics

View full text Add to dashboard Cite

The hourly data of the vertical Z and the horizontal H components of 37 ground–based DC–ULF geomagnetic stations are examined during 20 April–12 May 2008. On 9 May 2008, three days before the WenchuanM S 8.0 shock, anomalies — a double low‐point and a decreased amplitude — are registered on the curves of the Z component at 25 stations in a large‐scale area surrounding the Wenchuan epicentral area. The H component shows none of the double low‐point phenomenon but does exhibit a reduced magnitude at the same time. The geomagnetic index Kp is also examined and indicates that the anomalies appear at a solar quiet period. The appearing time shift (Tzs ) between the first low‐point on May 9 and the minimum point occurring time of May 1–5, 2008 is also checked. The results show that Tzs is on the order of 1–2 hours earlier or later than usual and there is a 2–6 hours’ gap between these two low‐points. However, there is still a transition area which includes the epicenter where Tzs = 0. Variation amplitude examined on vertical Z increases as the distance from the epicenter decreases. An Earth–air–ionosphere model has been employed to investigate a possible mechanism of this phenomenon and positive results have been unexpectedly attained. All these above‐related results tend to prove that the variations of the Z and H on May 9, 2008 during the solar quiet period are probably associated with the forthcoming Wenchuan M S 8.0 earthquake.

show abstract

“…Že v preteklosti so meritve geomagnetnega polja pokazale, da je magnetno polje ob polni luni in mlaju različno (Fraser-Smith, 1969). Vpliv Sonca in Lune na magnetno polje Zemlje so obravnavali za posamezne geomagnetne observatorije (Klausner et al, 2013;Bilge in Tulunay, 1997;Anad et al, 2008), področja geomagnetnega ekvatorja (Yizengaw in Carter, 2017;Soddoqui, 2017), celine (Cambell et al, 1998;Obiekezie Obiadazie in Agbo, 2013) in obdobja, daljša od deset let (Yamazaki et al, 2012;Yamazaki in Koch, 2014;Courtillot in Le Mouel, 1988). Uporabljali so različne metode obdelave merilnih podatkov, pri čemer v novejših raziskavah izstopajo analize z valčki (angl.…”

Section: Vpliv Sonca In Lune Na Magnetno Polje Zemljeunclassified

“…Na podlagi terenskih geomagnetnih meritev ter zbranih priporočil in podatkov je bila za izbiro primernega mesta za geomagnetni observatorij na ozemlju Slovenije narejena obsežna študija GIS (Paliska et al, 2010). Najprej je bil vzpostavljen observatorij na Sinjem Vrhu (SNV), in sicer na visokogorski planoti Gora nad Ajdovščino.…”

Section: Geomagnetni Observatorij V Slovenijiunclassified

Untitled

2020

geod. vestn.

View full text Add to dashboard Cite

Day-to-Day Variability of H and Z Components of the Geomagnetic Field at the African Longitudes

Cited by 15 publications

References 18 publications

Sq solar variation at Medea Observatory (Algeria), from 2008 to 2011

Sq solar variation at Medea Observatory (Algeria), from 2008 to 2011

Anomalous phenomena in DC–ULF geomagnetic daily variation registered three days before the 12 May 2008 Wenchuan <i>M</i><sub>S</sub> 8.0 earthquake

Untitled

Contact Info

Product

Resources

About