Creation of homogeneous composite climatological reference series

Abstract Most techniques used to adjust climatological time series for inhomogeneities require a homogeneous reference series for comparison with each time series being evaluated. However, creating homogeneous reference series from data with unknown inhomogeneities presents many obstacles. Although a truly homogeneous reference series may, in fact, not be obtainable, in this article we present a method that has proven successful at minimizing inhomogeneities in the creation of reference climatological time series. The method utilizes a multistep process based on non‐parametric statistics and an alternative way of relating two time series through correlation analysis. This alternative uses the year‐to‐year change in the variable under consideration (e.g. temperature) as the basis for correlation.