Morlet and GWPS of monthly sunspot numbers obtained from the dynamo model with fluctuations in the BMR time delay. Panels (a–b): Short-term or Rieger-type periodicities. Panels (c–d): QBOs and other long-term periods including the main cycle period corresponding to the 11 year solar cycle. The dotted red lines in all GWPS represent the 95% confidence level and black dotted lines in Morlet wavelet spectra represent COI.