Surface fractal characteristics of preferential flow patterns in field soils: evaluation and effect of image processing

被引:35
作者
Ogawa, S
Baveye, P
Boast, CW
Parlange, JY
Steenhuis, T
机构
[1] Cornell Univ, Dept Agr & Biol Engn, Ithaca, NY 14853 USA
[2] Cornell Univ, Lab Environm Geophys, Ithaca, NY 14853 USA
[3] Univ Illinois, Dept Nat Resources & Environm Sci, Urbana, IL 61801 USA
关键词
mass fractal dimensions; surface fractal dimensions; preferential flow patterns; field soils; quadratic von Koch island;
D O I
10.1016/S0016-7061(98)00101-3
中图分类号
S15 [土壤学];
学科分类号
0903 ; 090301 ;
摘要
In the last few decades, preferential flow has become recognized as a process of great practical significance for the transport of water and contaminants in field soils. Dyes are frequently used to visualize preferential flow pathways, and fractal geometry is increasingly applied to the characterization of these pathways via image analysis, leading to the determination of 'mass' and 'surface' fractal dimensions. Recent work by the authors has shown the first of these dimensions to be strongly dependent on operator choices (related to image resolution, thresholding algorithm, and fractal dimension definition), and to tend asymptotically to 2.0 for decreasing pixel size. A similar analysis is carried out in the present article in the case of the surface fractal dimension of the same stained preferential flow pathway, observed in an orchard soil. The results indicate that when the box-counting, information, and correlation dimensions of the stain pattern are evaluated via non-linear regression, they vary anywhere between 1.31 and 1.64, depending on choices made at different stages in the evaluation. Among the parameters subject to choice, image resolution does not appear to exert a significant influence on dimension estimates. A similar lack of dependency on image resolution is found in the case of a textbook surface fractal, the quadratic von Koch island. These parallel observations suggest that the observed stain pattern exhibits characteristics similar to those of st surface fractal. The high statistical significance (R > 0.99) associated with each dimension estimate lends further credence to the fractality of the stain pattern. However, when proper attention is given to the fact that the theoretical definition of the surface 'fractal' dimension, in any one of its embodiments, involves the passage to a limit, the fractal character of the stain pattern appears more doubtful. Depending on the relative weight given to the available pieces of evidence, one may conclude that the stain pattern is or is net a surface fractal. However, this conundrum may or may not have practical significance. Indeed, whether or not the stain pattern is a surface fractal, the avenging method proposed in the present article to calculate surface dimensions yields relatively robust estimates, in the sense that they are independent of image resolution. These dimensions, even if they are not 'fractal', may eventually play an important role in future dynamical theories of preferential flow in field soils. (C) 1999 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:109 / 136
页数:28
相关论文
共 31 条
[1]  
BAILAR J, 1990, SOIL MICROMORPHOLOGY, P25
[2]   Influence of image resolution and thresholding on the apparent mass fractal characteristics of preferential flow patterns in field soils [J].
Baveye, P ;
Boast, CW ;
Ogawa, S ;
Parlange, JY ;
Steenhuis, T .
WATER RESOURCES RESEARCH, 1998, 34 (11) :2783-2796
[3]  
Baveye P, 1997, ADV SOIL S, P1
[4]  
BEVEN K, 1991, PREFERENTIAL FLOW, P1
[5]  
BOAST CW, UNPUB PATTERN RECOGN
[6]   CASE-STUDY ON INFILTRATION INTO DRY CLAY SOIL .1. MORPHOLOGICAL OBSERVATIONS [J].
BOUMA, J ;
DEKKER, LW .
GEODERMA, 1978, 20 (01) :27-40
[7]  
CRAWFORD JW, IN PRESS ADV INFORMA
[8]  
Cullen S.J., 1995, HDB VADOSE ZONE CHAR, P61
[9]  
De Cola L., 1993, FRACTALS GEOGRAPHY, P3
[10]  
FALCONER K, 1992, FRACTAL GEOMETRY MAT