A music synthesizer can be thought of as generating
a lot of sine waves, then layering them to create an array of sounds.
Not exact matches
You need to look at tools for identifying a periodic (or quasiperiodic) signal on top
of a base trend that is NOT linear; because there's a heck
of a
lot more going on with climate that you can capture on such scales with one line a
sine wave.
Using spectral analysis
of data series will give you
sine waves — but does mean that the Sun has a whole
lot of processes going on to give independent cycles
of various periodicity?