Parameters

1991

1998

2005

2013

Range

A

218,800

219,000

227,500

230,800

Nugget

C₀

0.0603

0.029

0.049

0.0505

Sill

C₀ + C

0.3716

0.401

0.468

0.34

Nugget coefficient

C₀/C₀ + C

0.1622

0.03125

0.1047

0.1485

Fitting model

Model

Spherical

Spherical

Spherical

Spherical

Coefficient of determination

R²

0.646

0.755

0.831

0.908