Modelli per serie storiche circolari

as angles; for this reason, they are referred to as circular variables. Typical examples include wind direction, wave direction, or an animal’s movement direction, as well as the timing of physiological or behavioral events, such as the onset of a sym- ptom or the start of an activity. The cyclical nature of the measurement scale makes most of the summary measures commonly used for real-valued data inap- plicable. In this work, we review the main analytical methods suitable for this set- ting, with particular focus on circular time series, that is, sequences of observations of a circular variable collected over time, typically at equally spaced time points.