太阳与地磁活动的1.3–1.7 yr振荡关系分析

Analysis of the 1.3–1.7 yr Oscillation Relationship between Solar and Geomagnetic Activities

太阳和地磁活动中的1.3–1.7 yr周期研究对于理解日地空间耦合系统中可能发生的物理过程十分重要.黑子是太阳光球层上最突出的磁场结构, Ap指数则是表征全球地磁活动水平的重要指标.使用同步压缩小波变换得到太阳黑子数和地磁Ap指数的1.3–1.7yr周期,并用互相关方法分析研究它们之间的相位关系.结果如下:(1)太阳黑子数和地磁Ap指数的1.3–1.7 yr周期呈现间歇性的演化特征,且随着时间的变化而不断变化;(2)地磁Ap指数在奇数活动周比相邻的偶数活动周的周期分量更高,表现出上下波动的变化特性;(3)地磁Ap指数和太阳黑子数的相位关系不是一成不变的,在大多数情况下地磁Ap指数滞后太阳黑子数,仅在第18和第22活动周黑子数在相位上滞后.

The 1.3-1.7 yr periodic study of solar and geomagnetic activities is very important for understanding the possible physical processes in the solar-terrestrial coupling system.The sunspot is the most prominent magnetic field structure in the solar photosphere,and the Ap index is an important indicator of global geomagnetic activity.The 1.3-1.7 yr period of the sunspot number and the geomagnetic Ap index is obtained by the synchro-squeezing wavelet transform,and the phase relationship between them is studied by cross-correlation analysis.The main results are as following:(1)The 1.3-1.7 yr periods of the geomagnetic Ap index and sunspot number exhibit intermittent evolutionary characteristics,and change with time;(2)the geomagnetic Ap index has a higher periodic component in odd solar cycles than the neighboring even solar cycles,which is characterized by fluctuations;(3)the phase relationship between geomagnetic Ap index and sunspot number is not always consistent,in most cases the geomagnetic Ap index lags behind the sunspot number,except in the 18th and 22th solar cycles.