Geostatistical modelling of spatial processes on directed trees: Application to fluvisol extent

• Published in: Geoderma 2005-10, Vol.128 (3), p.179-191
• Main Authors: Monestiez, P., Bailly, J.-S., Lagacherie, P., Voltz, M.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Directed tree; Drift modelling; Earth sciences; Earth, ocean, space; Environmental Sciences; Exact sciences and technology; Fluvisols; Fundamental and applied biological sciences. Psychology; Geostatistics; Hydrographic network; Hérault river; Random function simulation; Soils; Surficial geology
• ISSN: 0016-7061; 1872-6259
• DOI: 10.1016/j.geoderma.2005.04.002

This paper shows that geostatistical modelling can be extended to spatial supports such as directed trees and applied to variables spatially structured along a river network. Specific assumptions were necessary and main methods were redefined introducing modifications on metrics, proper variogram estimates and ad hoc drift models. We also proposed a model-based simulation procedure to generate random functions on directed trees. A case study on fluvisol delineation for the Hérault river (South of France) was analyzed. Clear spatial structures were observed and modelled using variogram based on upstream–downstream distance along a hydrographic network. A drift was also modelled as a multiplicative term affecting the fluvisol width versus the cumulated length of the upstream network. The significance of the drift was then assessed conditionally to the former spatial variogram using Monte-Carlo simulations of the spatial observed process on the river network.