The nugget, sill, and range all increased with an increase in soil moisture.
Legend: Cc (partial sill); a (range, m) Fig. 7 Soil CO2 flux distribution maps for Furnas Lake (a) and Furnas Village (b) fumarolic ground.
A semi-variogram is a monotonic increasing function of the distance between x and x ′, and can be characterized by its sill and range.
In our approach, there are 119 model parameters (72 transmissivity values at the pilot points, 45 values of the vertical leakage coefficient, and two parameters (sill and range) for the isotropic variogram).
The sample variograms that represented the spatial structure of soil moisture and reliably estimated the nugget, sill, and range required a sample size of at least 235 at our 0.15-ha site (i.e., a measurement resolution of at least 6.4 m2 per sample).
λ j s and λ j r are the optimal weights estimated using maximum likelihood based on the spatial coefficients (sill and range) of θ[ 27, 28].
To obtain a succinct statistical description of the spatial correlation three different parametric models (exponential, Gaussian, and spherical) were fitted to the empirical semivariogram, each of which can be described in terms of nugget, sill and range parameters[ 17].
Regarding the HM concentrations in the soil samples, the nugget-to-sill ratio ranged between 37% (for Cd in 1995) and 72% (for Pb in 2005).
The corresponding sill, nugget, and range values were observed.
The important features of the variogram are range, sill, and nugget effect.
