MORLET TRANSFORM OF SUNSPOT NUMBER AND Ap INDEX

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.