Sensitivity Analysis in Variogram Estimation: Detecting Observations Influential to Cressie and Hawkins(1980) s Robust Variogram

As a continuation to the study of the sensitivity analysis in the sample variograms (Choi and Tanaka, 1999), the present article proposes a method to detect observations which are influential to the robust variograms. To do this, we derive the influence function for Cressie and Hawkins (1980)s robust variograms assuming that the underlying process of the observed spatial data is second-order stationary. A real numerical example is analyzed to show the validity or usefulness of the proposed influence function.