Showing papers by "Marcel G. Schaap published in 2019"
TL;DR: In this paper, the authors discuss the history of the development of the concept of saturated hydraulic conductivity and its relation to the Kozeny-Carman (KC) equation.
101 citations
TL;DR: In this article, 13 PTF ensembles were grouped according to input data requirements and evaluated against a well-documented soil database with global coverage, and the full 13-member set of PTFs were shown to have improved performance over individual PTF models in terms of root mean square error and other model selection criteria.
Abstract: A correct quantification of mass and energy exchange processes among land surface and atmosphere requires an accurate description of unsaturated soil hydraulic properties. Soil pedotransfer functions (PTFs) have been widely used to predict soil hydraulic parameters. Here, 13 PTFs were grouped according to input data requirements and evaluated against a well-documented soil database with global coverage. Weighted ensembles (calibrated by four groups and the full 13-member set of PTFs) were shown to have improved performance over individual PTFs in terms of root mean square error and other model selection criteria. Global maps of soil water retention data from the ensemble models as well as their uncertainty were provided. These maps demonstrate that five PTF ensembles tend to have different estimates, especially in middle and high latitudes in the Northern Hemisphere. Our full 13-member ensemble model provides more accurate estimates than PTFs that are currently being used in earth system models.
6 citations