I'm trying to learn something about wavelets (I have my own crude fft code) using the http://climexp.knmi.nl/diffdat.cgifun [KNMI Climate Explorer tool](http://climexp.knmi.nl/diffdat.cgi)

I annually detrended and chose 64 bins (cf default 3) for the observed soim data as as a comparative model to your equation.


The other week I did some comparison between the observed data for 1880-1930, 1930-1975 and 1976-2014 and thought I could see different periodicities decreasing very roughly from 60, 40 to 20 yrs. Trouble is, I can't remember if I saved the images or how I produced them which is about as much help as a pogostick in quicksand :(.