Geoscience Reference
In-Depth Information
B, small variations (Nugget effects) of NDVI images in 1999/10/31 are larger than
those in other images. As the range of a variogram model increases, the continuity of
an NDVI image increases. The ranges of NDVI variogram models in area A from long
range to short range are in 2000/11/27, 2001/11/20, 1999/03/06, 1996/11/08, 1999/10,
2003/12/17, and 2004/11/19. In area B, the ranges of NDVI variogram models from
long range to short range are in 1999/03/06, 2000/11/27, 2003/12/17, 2004/11/19,
2001/11/20, 1996/11/08, and 1999/10. However, exponential models with large sills,
large nugget effects and short-range NDVI images are indicative of signifi cant spatial
heterogeneous landscapes induced by the Chi-Chi earthquake in areas A and B. More-
over, typhoons Xangsane and Dujuan generated heterogeneous landscapes in area A.
Table 2.
Variogram models of NDVI images.
Area
Date
Model
Parameters
The fi t
Cross-validate
1996/11/08
Exponential model
Co=0.000453,
Co+C=0.001212,
R=1204.000
(SS=7.774E-08;
r
2
=0.832,
Co/Co+C=0.374)
r
2
=0.722
1999/03/06
Exponential model
Co=0.000147,
C0+C=0.001744;
R=1278.000
(SS=3 .490E-08;
r
2
=0.873,
Co/Co+C=0.352)
r
2
=0.893
1999/10/31
Exponential model
Co=0.000878,
Co+C=0.002496;
R=1020.000
(SS=18.597E-08;
r =0.961,
Co/Co+C=0.310)
r
2
=0.839
2000/11/27
Exponential model
Co=0.000761,
Co+C=0.002452;
R=1881.000
(SS=5.124E-08;
r =0.878,
Co/Co+C=0.400)
r
2
=0.894
A
2001/11/20
Exponential model
Co=0.000518,
Co+C=0.001294;
R=1497.000
(SS=5.124E-08;
r =0.878,
Co/Co+C=0.400)
r
2
=0.723
2003/12/17
Exponential model
Co=0.000700,
Co+C=0.003370;
R=981.000
(SS=3.420E-07;
r
2
= 0.893,
Co/Co+C=0.208)
r
2
=0.737
2004/11/19
Exponential model
Co=0.000229,
Co+C=0.002878;
R=918.000
(SS=1.918E-07;
r
2
= 0.930,
Co/Co+C=0.080)
r
2
=0.862
1996/ 11/08
Exponential model
Co=0.000138,
Co+C=0.001326;
R=654.000
(SS=1.610E-08;
r
2
=0.953,
Co/Co+C=0.104)
r
2
=0.781
1999/03/06
Exponential model
Co=0.000712,
Co+C=0.001814;
R=4620.000
(SS=6.070E-08;
r
2
=0.945,
Co/Co+C=0.393)
r
2
=0.901
1999/10/31
Exponential model
Co=0.000590,
Co+C=0.004440;
R=564.000
(SS= 1.678E-07;
r
2
=0.939,
Co/Co+C=0.133)
r
2
=0.849
2000/11/127
Exponential model
Co=0.0001863
Co+C=0.004676;
R=2646.000,
(SS=2.474E-07;
r
2
=0.952,
Co/Co+C=0.398)
r
2
=0.908
B
2001/11/20
Exponential model
Co=0.0001205,
Co+C=0.002429;
R=1281.000
(SS=5 .621E-08;
r
2
=0.933,
Co/Co+C=0.498)
r
2
=0.728
2003/12/17
Exponential model
Co=0.0001258,
Co+C=0.003126;
R=2298.000
(SS= 1.567E-07;
r
2
=0.949,
Co/Co+C=0.402)
r
2
=0.820
2004/11/19
Exponential model
Co=0.0001161,
Co+C=0.003832;
R=1680.000
(SS= 1.186E-07;
r
2
=0.977,
Co/Co+C=0.303)
r
2
=0.902
Co=Nugget; Co+C=Sill; R= Range
