Further Simulation Results on Resampling Confidence Intervals for Empirical Variograms

Clark and Allingham (2010) described and evaluated a number of replication-based confidence intervals for the binned empirical variogram. All were based on fiing an exponential variogram model to two-dimensional spatial data. This article will hereafter be referred to as CA10. CA10 evaluated the coverage of the various confince intervals by simulating spatial data. Datasets were simulated using multivariate normal or lognormal distributions, with the exponential or Gaussian variogram, with diffing efftive ranges. The Gaussian vario- gram was included to assess the robustness of the intervals to the assumption that spatial correlations followed an exponential variogram model. This note further explores the robustness of the confince intervals to mis-specifition of the variogram, by extending the simulations of CA10 to include cubic and spherical variogram models. Confince intervals were calculated based on an assumption of an exponential variogram model, as in CA10.