Decomposing Time Series

A time series \(y_t\) can be splitted up into trend component \(\tau_t\), seasonal component \(s_t\) and the remainder \(u_t\).

$$\begin{aligned} y_t = \tau_t + s_t + u_t \end{aligned}$$

In R the function stl() can be used for seasonal decomposition of a time series.