摘要
利用2004—2006年ACE、WIND卫星观测的太阳风数据和相应时期反映磁暴大小的Dst指数,针对200个不同级别的磁暴事件,分析了磁层顶日下点距离R0与磁暴Dst指数的线性相关性。分析显示,在极端太阳风条件下,Dst指数时间序列比借助于Chao Model计算出的磁层顶日下点距离R0的时间序列延迟了约3h。经修正时间延迟后,对磁层顶日下点距离R0与磁暴Dst指数的线性相关性进行分析。结果表明:发生超级磁暴时,二者线性相关系数的均值为0.77;大磁暴时,线性相关系数的均值为0.74;中等磁暴时,线性相关系数的均值为0.47。此外,用最小二乘数据拟合得到了不同级别磁暴时的R0-Dst关系图。
With the solar wind data observed by ACE/WIND spacecraft and the geomagnetic storm Dst index data during 2004—2006,the linear correlation between magnetopause standard off distance R0 and Dst index,in which the grade of geomagnetic storm is characterized,is investigated in terms of 200 different graded storms.It is a fact that the time series of Dst index lag about 3 h behind the time series of the magnetopause standard off distance R0 calculated by Chao Model under the extreme solar wind.After the time lag corrected,the linear correlation between magnetopause standard off distance R0 and geomagnetic storm Dst index is revealed.The results show that the average linear correlation coefficients are 0.77,0.74 and 0.47,respectively,corresponding to the super,the big and the middle storms.Under different graded storms,the charts of R0-Dst fitted by the least square method are shown.
出处
《大气科学学报》
CSCD
北大核心
2011年第4期504-509,共6页
Transactions of Atmospheric Sciences
基金
国家自然科学基金资助项目(60973157)
关键词
磁层顶日下点距离
磁暴
线性相关系数
最小二乘拟合方法
magnetopause standard off distance
geomagnetic storm
linear correlation coefficient
least square method
