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  4. 中国科学院地球与行星物理重点实验室
Quasi-biennial oscillations in the geomagnetic field: Their global characteristics and origin

文献类型：期刊论文

作者Ou, Jiaming1; Du, Aimin1; Finlay, Christopher C.2
刊名JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
出版日期2017-05-01
卷号122期号:5页码:5043-5058
ISSN号2169-9380
DOI10.1002/2016JA023292
文献子类Article
英文摘要Quasi-biennial oscillations (QBOs), with periods in the range 1-3years, have been persistently observed in the geomagnetic field. They provide unique information on the mechanisms by which magnetospheric and ionospheric current systems are modulated on interannual timescales and are also of crucial importance in studies of rapid core field variations. In this paper, we document the global characteristics of the geomagnetic QBO, using ground-based data collected by geomagnetic observatories between 1985 and 2010, and reexamine the origin of the signals. Fast Fourier transform analysis of second-order derivatives of the geomagnetic X, Y, and Z components reveals salient QBO signals at periods of 1.3, 1.7, 2.2, 2.9, and 5.0years, with the most prominent peak at 2.2years. The signature of geomagnetic QBO is generally stronger in the X and Z components and with larger amplitudes on geomagnetically disturbed days. The amplitude of the QBO in the X component decreases from the equator to the poles, then shows a local maximum at subauroral and auroral zones. The QBO in the Z component enhances from low latitudes toward the polar regions. At high latitudes (poleward of 50 degrees) the geomagnetic QBO exhibits stronger amplitudes during LT 00:00-06:00, depending strongly on the geomagnetic activity level, while at low latitudes the main effect is in the afternoon sector. These results indicate that the QBOs at low-to-middle latitudes and at high latitudes are influenced by different magnetospheric and ionospheric current systems. The characteristics of the multiple peaks in the QBO range are found to display similar latitudinal and local time distributions, suggesting that these oscillations are derived from a common source. The features, including the strong amplitudes seen on disturbed days and during postmidnight sectors, and the results from spherical harmonic analysis, verify that the majority of geomagnetic QBO is of external origin. We furthermore find a very high correlation between the geomagnetic QBO and the QBOs in solar wind speed and solar wind dynamic pressure. This suggests the geomagnetic QBO primarily originates from the current systems due to the solar wind-magnetosphere-ionosphere coupling process.
WOS关键词HIGH-SPEED STREAMS ; SOLAR-WIND SPEED ; MAGNETIC-FIELD ; RING CURRENT ; 27-MONTH PERIODICITY ; SPECTRAL-ANALYSIS ; MODEL ; INDEX ; INTERPLANETARY ; MAGNETOSPHERE
WOS研究方向Astronomy & Astrophysics
语种英语
WOS记录号WOS:000403912500013
出版者AMER GEOPHYSICAL UNION
资助机构National Basic Research Program of China(2014CB845903 ; National Basic Research Program of China(2014CB845903 ; National Natural Science Foundation of China(41174122 ; National Natural Science Foundation of China(41174122 ; 2012CB825604) ; 2012CB825604) ; 41031066 ; 41031066 ; 41104093 ; 41104093 ; 41504057 ; 41504057 ; 41574162 ; 41574162 ; 41590851 ; 41590851 ; 41204122) ; 41204122) ; National Basic Research Program of China(2014CB845903 ; National Basic Research Program of China(2014CB845903 ; National Natural Science Foundation of China(41174122 ; National Natural Science Foundation of China(41174122 ; 2012CB825604) ; 2012CB825604) ; 41031066 ; 41031066 ; 41104093 ; 41104093 ; 41504057 ; 41504057 ; 41574162 ; 41574162 ; 41590851 ; 41590851 ; 41204122) ; 41204122) ; National Basic Research Program of China(2014CB845903 ; National Basic Research Program of China(2014CB845903 ; National Natural Science Foundation of China(41174122 ; National Natural Science Foundation of China(41174122 ; 2012CB825604) ; 2012CB825604) ; 41031066 ; 41031066 ; 41104093 ; 41104093 ; 41504057 ; 41504057 ; 41574162 ; 41574162 ; 41590851 ; 41590851 ; 41204122) ; 41204122) ; National Basic Research Program of China(2014CB845903 ; National Basic Research Program of China(2014CB845903 ; National Natural Science Foundation of China(41174122 ; National Natural Science Foundation of China(41174122 ; 2012CB825604) ; 2012CB825604) ; 41031066 ; 41031066 ; 41104093 ; 41104093 ; 41504057 ; 41504057 ; 41574162 ; 41574162 ; 41590851 ; 41590851 ; 41204122) ; 41204122)
源URL[http://ir.iggcas.ac.cn/handle/132A11/50668]  
专题地质与地球物理研究所_中国科学院地球与行星物理重点实验室
通讯作者Du, Aimin
作者单位1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Earth & Planetary Phys, Beijing, Peoples R China
2.Tech Univ Denmark, Div Geomagnetism, DTU Space, Lyngby, Denmark
推荐引用方式
GB/T 7714		 Ou, Jiaming,Du, Aimin,Finlay, Christopher C.. Quasi-biennial oscillations in the geomagnetic field: Their global characteristics and origin[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,2017,122(5):5043-5058.
APA Ou, Jiaming,Du, Aimin,&Finlay, Christopher C..(2017).Quasi-biennial oscillations in the geomagnetic field: Their global characteristics and origin.JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,122(5),5043-5058.
MLA Ou, Jiaming,et al."Quasi-biennial oscillations in the geomagnetic field: Their global characteristics and origin".JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 122.5(2017):5043-5058.

入库方式： OAI收割

来源：地质与地球物理研究所

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