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

Autor: Abdeslam Abtout, F. Anad, Mohamed Hamoudi, Endawoke Yizengaw, Seid Bourouis, C. Amory-Mazaudier
Přispěvatelé: Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG), Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Abdus Salam International Centre for Theoretical Physics [Trieste] (ICTP), Université des Sciences et de la Technologie Houari Boumediene [Alger] (USTHB), Institute for Scientific Research [Newton] (ISR), Boston College (BC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université des Sciences et de la Technologie Houari Boumediene = University of Sciences and Technology Houari Boumediene [Alger] (USTHB)
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Advances in Space Research
Advances in Space Research, Elsevier, 2016, ⟨10.1016/j.asr.2016.06.029⟩
Advances in Space Research, 2016, ⟨10.1016/j.asr.2016.06.029⟩
ISSN: 0273-1177
DOI: 10.1016/j.asr.2016.06.029⟩
Popis: International audience; This 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.
Databáze: OpenAIRE
Externí odkaz: