太阳黑子数及Ap指数周期变化特征的小波分析

MORLET TRANSFORM OF SUNSPOT NUMBER AND Ap INDEX

应用Morlet小波变换方法从多个变化尺度上对1932-2000年的太阳黑子数及Ap指数的变化特征进行分析. (1)太阳黑子数存在准11年、准32年的周期变化特征及Ap指数存在准32年、准11年、准6个月、准27天和准13.9天的周期变化特征;(2)太阳黑子数及Ap指数有着相似的准11年周期变化,但Ap指数极值的出现要比太阳黑子数极值出现滞后1-2年; (3)AP指数准27天的周期变化在太阳黑子活动高、低年不同,在太阳活动低年,Ap指数有着较稳定的准27天周期变化,但在太阳活动高年, 27天的周期变化几乎消失,这种周期变化的消失和出现时间可在Morlet小波变换图中体现出来.

In this paper, Morlet wavelet transformation is applied to analyze the character of sunspot number and Ap index from 1932 to 2000 including solar cycle 17 to the rising phase of solar cycle 23. By the several examples selected during solar maximum and minimum respectively, three conclusion are drawn: (1) Sunspot number and Ap index both have obvious 11-year period and 32-year period, and Ap index also has 6-month period that exist in all phase, 27-day period and 13.9-day period. (2) Compared with the 11-year period of sunspot number, the maximum value of Ap index appears one or two years latter than that of sunspot number. (3) The 27-day period of Ap index is different during solar maximum and solar minimum. During solar minimum, Ap index has stable 27-day period. But during solar maximum, the character of 27-day period disappears or changes. And wavelet transformation could show detailed time when 27-day period vanishes and recurs.