A study on variations of non-dipole magnetic field over Chinese mainland during 2000 BC to 1990 AD

doi:10.1007/s11430-013-4674-6

	A study on variations of non-dipole magnetic field over Chinese mainland during 2000 BC to 1990 AD
	Feng Yan 1; Jiang Yong 1; Sun Han 2; An ZhenChang 3; Mao Fei 4
刊名	SCIENCE CHINA-EARTH SCIENCES
	2014-06-01
卷号	57 期号:6 页码:1229-1244
关键词	non-dipole geomagnetic field CALS3K.4 IGRF11
ISSN号	1674-7313
DOI	10.1007/s11430-013-4674-6
文献子类	Article
英文摘要	We calculated and analyzed variation of the non-dipole (ND) magnetic field at the millennium scale over the Chinese mainland during 2000 BC-1900 AD using the newest global geomagnetic model, CALS3K.4 (3K.4). The newest-generation IGRF (IGRF11) was used to verify the results. Taking component Z for example, we calculated and analyzed the distribution and annual change rates of the ND field during 1900-1990 AD every 5 yr, using two models. To thoroughly analyze the contributions of field sources, quadrupole and octupole fields, and others within the ND field at the surface and core-mantle boundary (CMB) were investigated. Results show that there were three main variation phases of the field during the period 2000 BC-1900 AD. The mean amplitude roughly reflected the ND field because of the distribution and variation of that field, corresponding somewhat to the mean amplitude change. A magnetic anomaly of the ND field over East Asia (EA) first emerged in 1682 AD, and its extreme intensity had increased a total of 15276.95 nT by 1900 AD. Its location moved continuously southeastward after 1690 AD. The asymmetry between location and intensity of extreme points over EA, particularly during 1740-1760 AD, indicates irregularity of fluid motion inside the outer core. Mean annual changes of Z are generally divided into four phases, which first oscillated between 2000 and 800 BC, then increased, decreased and increased in the periods 800 BC-300 AD, 300-900 AD and 900-1900 AD, respectively. The intensity of mean annual change increased a total of 22.87 nT/yr. Anomaly extreme locations based on 3K.4 and IGRF11 over EA centered around 44A degrees N and 103A degrees E for degree (n) greater than 5, and intensities continuously increased with n. During 2000 BC-1990 AD, ND energy of Z at the surface and CMB had decreased in total by 18.29% and 23.23%, respectively. The field source of 2(6)-2(10) pole fields are more or less affected by the lithospheric field. Energies of higher degree at the surface attenuate by almost 99% compared with CMB, but mean attenuation speeds of the low-degree ND field are faster than high-degree, which implies that the low-degree ND field has a deeper source.
WOS关键词	GEOMAGNETIC SECULAR VARIATION ; CORE-MANTLE BOUNDARY ; PAST 3000 YEARS ; SATELLITE DATA ; EARTHS CORE ; MODEL ; GENERATION ; CHAMP ; TIME
WOS研究方向	Geology
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000336380400010
资助机构	National Natural Science Foundation of China(41174165) ; National Natural Science Foundation of China(41174165) ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; NUIST(20110420) ; NUIST(20110420) ; GYHY200906033) ; GYHY200906033) ; National Natural Science Foundation of China(41174165) ; National Natural Science Foundation of China(41174165) ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; NUIST(20110420) ; NUIST(20110420) ; GYHY200906033) ; GYHY200906033) ; National Natural Science Foundation of China(41174165) ; National Natural Science Foundation of China(41174165) ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; NUIST(20110420) ; NUIST(20110420) ; GYHY200906033) ; GYHY200906033) ; National Natural Science Foundation of China(41174165) ; National Natural Science Foundation of China(41174165) ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; Special Project for Meteo-scientific Research in the Public Interest(GYHY201306073-2 ; NUIST(20110420) ; NUIST(20110420) ; GYHY200906033) ; GYHY200906033)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/86066]
专题	中国科学院地质与地球物理研究所
通讯作者	Jiang Yong
作者单位	1.Nanjing Univ Informat Sci & Technol, Coll Math & Phys, Nanjing 210044, Jiangsu, Peoples R China 2.Natl Satellite Meteorol Ctr, Remote Sensing Applicat & Expt Stn, Nanning 530022, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 4.Chinese Acad Meteorol Sci, Beijing 100081, Peoples R China
推荐引用方式 GB/T 7714	Feng Yan,Jiang Yong,Sun Han,et al. A study on variations of non-dipole magnetic field over Chinese mainland during 2000 BC to 1990 AD[J]. SCIENCE CHINA-EARTH SCIENCES,2014,57(6):1229-1244.
APA	Feng Yan,Jiang Yong,Sun Han,An ZhenChang,&Mao Fei.(2014).A study on variations of non-dipole magnetic field over Chinese mainland during 2000 BC to 1990 AD.SCIENCE CHINA-EARTH SCIENCES,57(6),1229-1244.
MLA	Feng Yan,et al."A study on variations of non-dipole magnetic field over Chinese mainland during 2000 BC to 1990 AD".SCIENCE CHINA-EARTH SCIENCES 57.6(2014):1229-1244.