Search for evidence of a clock related to the solar 154 day complex of periodicities

Evidence indicates that the 154-day periodicity in solar activity may be part of a complex of periodicities that are approximate multiples of 25.8 d, which suggests that the sun contains a 'clock' with frequency in the range 440-463 nHz. To search for evidence of this clock, the daily Greenwich sunspot areas and daily Zurich sunspot numbers have been Fourier-analyzed. The Zurich data show a strong peak that may clearly be identified with the fundamental frequency, while the Greenwich data show a peak that may be the harmonic of the fundamental frequency. A model is discussed which provides a kinematical interpretation of the sunspot spectrum.