地震研究

根据CHAOS-6模型,计算了2015年中国地区28个地磁台站的地磁年度变化以及2008.0—2016.5年成都、格尔木、兰州、泰安和通海5个地磁台站的地磁长期变化。分析比较了地磁台站实际观测值与CHAOS-6模型计算值之间的差异,得到两者差值的均值及均方误差。结果表明:CHAOS-6模型描述的中国地区地磁长期变化与地磁台站实际观测的地磁长期变化趋势基本一致,但存在一定的差异,28个台站的磁偏角(D)、磁倾角(I)、地磁总强度(F)、北向分量(X)、东向分量(Y)、水平分量(H)、垂直分量(Z)差值的均值和均方误差的平均值分别为-0.9'/1.7',-29.3'/0.8',-116.3 nT/10.2 nT,264.7 nT/13.6 nT,-27.7 nT/15.0 nT,265.2 nT/13.7 nT,-356.9 nT/8.0 nT。因此,在使用CHAOS-6模型研究中国地区区域问题时,应充分考虑模型的误差大小。

According to the CHAOS-6 model,the annual changes of geomagnetic at 28 observations located in China in 2015 and the geomagnetic secular variations at CDP,GLM,LZH,TAA and THJ observations in 2008.0—2016.5 were calculated.The differences between the geomagnetic data of practical observations and those calculated by the CHAOS-6 model were analyzed.The mean differences and the mean square root σ were obtained.The results show that the trend of the geomagnetic secular variation in China described by the CHAOS-6 model is basically consistent with those at observations,but there are some differences.The mean of the difference and the mean square root are -0.9'/1.7' and -29.3'/0.8' for geomagnetic declination(D)and inclination(I)respectively; and the mean of the difference and the mean square root are -116.3 nT/10.2 nT,264.7 nT/13.6 nT,-27.7 nT/15.0 nT,265.2 nT/13.7 nT and -356.9 nT/8.0 nT for total intensity(F),northern component(X),eastern component(Y),horizontal component(H)and vertical component(Z),respectively at 28 observations.The main reason for the error of the geomagnetic secular variation in China described by the CHAOS-6 model is that the regional and local magnetic anomalies in China,while the CHAOS-6 is a model of global geomagnetic field.The error of the CHAOS-6 model should be fully considered when we use it to study the regional problems in China.

引言
1 地磁数据选取
2 地磁长期变化误差分析
3 讨论与结论

图1 中国地区28个地磁台站的分布示意图<br/>Fig.1 Schematic distribution map of the 28 geomagnetic observatory stations in China

图1 中国地区28个地磁台站的分布示意图
Fig.1 Schematic distribution map of the 28 geomagnetic observatory stations in China

图2 2015年TSY台X分量观测数据与CHAOS-6模型计算数据的对比曲线(a)及其虚线框放大对比曲线(b)<br/>Fig.2 The comparison of X component from TSY observation and that calculated by the CHAOS-6 model(a)and its enlarged graph of 30 d in dotted frame(b)

图2 2015年TSY台X分量观测数据与CHAOS-6模型计算数据的对比曲线(a)及其虚线框放大对比曲线(b)
Fig.2 The comparison of X component from TSY observation and that calculated by the CHAOS-6 model(a)and its enlarged graph of 30 d in dotted frame(b)

表1 2015年地磁台站观测值与CHAOS-6模型计算值差值的均值avg及均方误差σ<br/>Tab.1 The mean value(avg)and mean square root σ of the differences between the geomagnetic data of practical observations and those calculated by the CHAOS-6 model in 2015

表1 2015年地磁台站观测值与CHAOS-6模型计算值差值的均值avg及均方误差σ
Tab.1 The mean value(avg)and mean square root σ of the differences between the geomagnetic data of practical observations and those calculated by the CHAOS-6 model in 2015

图3 磁偏角D(a)、磁倾角I(b)、总强度F(c)、北向分量X(d)、东向分量Y(e)、水平分量H(f)及垂直分量Z(g)的均方误差σ等值线分布[D、I的单位为('),F、X、Y、H、Z的单位为(nT)]<br/>Fig.3 Contour distribution map of the mean square root σ of D(a),I(b),F(c),X(d),Y(e),H(f),Z(g)(the unit of D and I is:',the unit of F、X、Y、H、Z is nT)

图3 磁偏角D(a)、磁倾角I(b)、总强度F(c)、北向分量X(d)、东向分量Y(e)、水平分量H(f)及垂直分量Z(g)的均方误差σ等值线分布[D、I的单位为('),F、X、Y、H、Z的单位为(nT)]
Fig.3 Contour distribution map of the mean square root σ of D(a),I(b),F(c),X(d),Y(e),H(f),Z(g)(the unit of D and I is:',the unit of F、X、Y、H、Z is nT)

图4 2008.0—2016.5年CDP(a)、LZH(b)、THJ(c)、GLM(d)及TAA(e)地磁台观测值与CHAOS-6模型计算值长期变化的差值曲线<br/>Fig.4 The difference curve of geomagnetic secular variation between the geomagnetic data of practical observations and those calculated by the CHAOS-6 model during 2008.0 and 2016.5 at CDP(a)、LZH(b)、THJ(c)、GLM(d)and TAA(e)stations

图4 2008.0—2016.5年CDP(a)、LZH(b)、THJ(c)、GLM(d)及TAA(e)地磁台观测值与CHAOS-6模型计算值长期变化的差值曲线
Fig.4 The difference curve of geomagnetic secular variation between the geomagnetic data of practical observations and those calculated by the CHAOS-6 model during 2008.0 and 2016.5 at CDP(a)、LZH(b)、THJ(c)、GLM(d)and TAA(e)stations

陈斌,顾左文,狄传芝,等.2012a.第11代国际地磁参考场[J].国际地震动态,(2):20-29.
陈斌,顾左文,高金田,等.2010.中国地区地磁长期变化研究[J].地球物理学报,53(9):2144-2154.
陈斌,顾左文,高金田,等.2011b.2005.0年代中国地区地磁场及其长期变化球冠谐和分析[J].地球物理学报,54(3):771-779.
陈斌,顾左文,高金田,等.2012c.IGRF-11描述的2005-2010年中国地区地磁长期变化及其误差分析[J].地球物理学进展,27(2):512-521.
陈斌.2011b.自然正交分量方法在地震地磁监测中的应用[J].地震研究,34(4):466-469.
傅承义,陈运泰,祁贵仲.1985.地球物理学基础[M].北京:科学出版社.
高金田,安振昌,顾左文,等.2006.用曲面Spline方法表示1900～1936年中国(部分地区)地磁场及其长期变化的分布[J].地球物理学报,49(2):398-407.
顾春雷,张毅,徐如刚,等.2010.地震前后岩石圈磁场变化特征分析[J].地球物理学进展,25(2):472-477.
顾左文,安振昌,高金田,等.2006b.2003年中国及邻区地磁场模型的计算与分析[J].地震学报,28(2):141-149.
顾左文,陈斌,高金田,等.2009.应用NOC方法研究中国地区地磁时空变化[J].地球物理学报,52(10):602-2612.
顾左文,张毅,姚同起,等.2006a.九江—瑞昌MS5.7地震地磁异常的观测与分析[J].地震学报,28(6):611-621.
倪喆,陈双贵,袁洁浩,等.2014a.芦山7.0级地震前后岩石圈磁场异常变化研究[J].地震研究,37(1):61-65.
倪喆.2014b.洱源5.5级地震前后地磁变化异常特征分析[J].地震研究,37(3):426-432.
徐文耀,魏志刚,夏国辉.2005.2000年中国地区地磁场长期变化的区域特征[J].地球物理学报,48(3):551-560.
徐文耀,朱岗昆.1984.我国及邻近地区地磁场的矩谐分析[J].地球物理学报,27(6):511-522.
徐文耀.2003.地磁学[M].北京:地震出版社.
徐文耀.2014.地磁活动性概论[M].北京:科学出版社.
袁洁浩,顾左文,陈斌,等.2013.地震与火山电磁研究的国际学术交流与合作[J].地震研究,36(1):132-140.
袁洁浩,顾左文,王粲,等.2016.2015年IUGG大会与世界华人地质大会的震磁研究进展[J].地震研究,39(4):703-708.
FINLAY C C,OLSEN N,KOTSIAROS S,et al.2016.Recent geomagnetic secular variation from Swarm and ground observatories as estimated in the CHAOS-6 geomagnetic field model[J].Earth Planets Space,68(1):112.
FINLAY C C,OLSEN N,TOEFFNER-CLAUSEN L.2015.DTU candidate field models for IGRF-12 and the CHAOS-5 geomagnetic field model[J].Earth Planets Space,67(1):114.
OLSEN N,LUEHR H,FINLAY C C,et al.2014.The CHAOS-4 geomagnetic field model[J].Geophys J Int,197(2):815-827.
OLSEN N,LUEHR H,SABAKA T J,et al.2006.CHAOS-a model of Earth's magnetic field derived from CHAMP,rsted,and SAC-C magnetic satellite data[J].Geophys J Int,166(1):67-75.
OLSEN N,MANDEA M,SABAKA T J,et al.2009.CHAOS-2-a geomagnetic field model derived from one decade of continuous satellite data[J].Geophys J Int,179(3):1477-1487.
OLSEN N,MANDEA M,SABAKA T J,et al.2010.The CHAOS-3 geomagnetic field model and candidates for the 11th generation of IGRF[J].Earth Planets Space,62:719-727.
OLSEN N,MANDEA M.2008.Rapidly changing flows in the Earth's core[J].Nature Geoscience,1(6):390-394.
XU W Y,XIA G H,A N Z C,et al.2003.Magnetic survey and China GRF2000[J].Earth Planets Space,55(4):215-217.

备注

引言

1 地磁数据选取

2 地磁长期变化误差分析

3 讨论与结论

期刊信息