Table 2. Estimated covariance parameters.

	OK	SLM	SLM-TF	RFRK
Nugget	278.08	257.17	226.78	261.08
Partial Sill	135.05	68.59	53.03	13.52
Range	139.09	189.31	167.98	100.66
Effective Range	485.03	576.87	494.19	160.44
Nugget-to-Sill Ratio	0.67	0.79	0.81	0.95

The effective range is the distance (km) beyond which spatial autocorrelation is less than 0.01, and the nugget-to-sill ratio is given by ${\widehat{\sigma }}_{ϵ}^2/({\widehat{\sigma }}_z^2+{\widehat{\sigma }}_{ϵ}^2)$.