Calculation[edit]
The location and scale measures used in forming an anomaly time-series may either be constant or may themselves be a time series or a map. For example, if the original time series consisted of daily mean temperatures, the effect of seasonal cycles might be removed using a deseasonalization filter.
Robust statistics, resistant to the effects of outliers, are sometimes used as the basis of the transformation.[1]
Examples[edit]
Atmospheric sciences[edit]
In the atmospheric sciences, the climatological annual cycle is often used as the expected value. Famous atmospheric anomalies are for instance the Southern Oscillation index (SOI) and the North Atlantic oscillation index. SOI is the atmospheric component of El Niño, while NAO plays an important role for European weather by modification of the exit of the Atlantic storm track. A climate normal can also be used to derive a climate anomaly.[2]