STATIONARY AND NON-STATIONARY DATA|L-4|ECONOMETRICS

Stationarity and nonstationarity are terms you may have encountered previously if you’ve taken water or climate related courses and are important for understanding changes in the Earth System. But what do these terms actually mean? A stationary time series has statistical properties or moments (e.g., mean and variance) that do not vary in time. Stationarity, then, is the status of a stationary time series. Conversely, nonstationarity is the status of a time series whose statistical properties are changing through time. This step explores examples of stationarity and nonstationarity.