摘要
地磁规则日变化的有效提取能够提高地磁活动指数现报的准确性.本文基于1998—2013年北京十三陵(BMT)台站的地磁数据,利用卡尔曼滤波(KF)方法提取了地磁场规则日变化(S_R)曲线.该方法提取的S_R曲线具有明显的逐日变化特征,能够准确反映S_R曲线的季节变化和地方时效应.根据KF方法得到的S_R日变幅度逐日变化的结果,改进了K指数的量算方法,重新计算了十三陵台站的K指数以及Ak指数,并分析了S_R日变幅度的逐日变化对K指数量算的改进程度.分析结果表明,当K≤3时,KF方法可以较好地改善S_R曲线扰动幅度的计算,提高了地磁规则日变化提取的有效性,从而改进相应的地磁活动指数的量算.
Defining Solar Regular（ S_R） geomagnetic variance can improve the accuracy of geomagnetic indices estimation. Based on geomagnetic data from 1998 to 2013 at Beijing Ming Tombs Observatory（ BMT） of China,Kalman filter technique is developed to define solar regular geomagnetic variation. The new algorithm can distinguish day-to-day（ DTD） variations of geomagnetic field ＇s regular variation and reflect both the diurnal and seasonal variations of magnetic disturbance. Based on DTD variations in the amplitude of S_R curve obtained by Kalman filter,we improved the evaluation of K index,recalculated the K and Ak index at BMT,and evaluated the improvements of K index estimation after taking account of DTD variations in S_R curve. The results showed that Kalman filter technique can improve the amplitude estimation of S_R when K≤3,then increase the accuracy of S_Rdefinition,which consequently improve the estimation of geomagnetic activity indices.
作者
陈果
杜爱民
张莹
赵旭东
CHEN Guo;DU Ai-min;ZHANG Ying;ZHAO Xu-dong(Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China;University of Chinese Academy of Sciences, Beijing 100049, China;Institute of Geophysics, China Earthquake Administration, Beijing 100081, China)
出处
《地球物理学进展》
CSCD
北大核心
2017年第5期1880-1885,共6页
Progress in Geophysics
基金
国家重点基础研究发展计划(2014CB845903
2012CB825604)
国家自然科学基金(41674168
41590851
41504129)
国家重大科学仪器设备开发专项项目(2014YQ100817)联合资助
关键词
卡尔曼滤波
地磁规则日变化
地磁活动指数
Kalman filter
solar regular geomagnetic variations
geomagnetic activity indices
