For me this is a very fascinating problem, which I however lack the ability to deal with as well as the nomenclature to describe properly. (Please feel free to edit the title).
The conditions are the following:
I have three volumes of air in which I measure the concentration of a chemical compound. So I have three sets of data: A, B and C, which describe the variation of the compound over time. The measurements are made synchronous with equal and constant time steps.
A is the outdoor air and is not influenced by neither B nor C.
B has its own unique variation due to some internal processes, but can to some extent be influenced by A.
C can be influenced by both A and B.
The big question is:
How can I determine which of A and B influence C and to what extent. A complicating factor is that there is a phase shift, which may vary. It can even be the case that A and B effect C alternately or simultaneously.
I have picked up that some form of Fourier function may come in handy.
What functions and approach would be productive?