Recent advances in pore-scale network modeling in vadose zone hydrology

The effective hydraulic properties of unsaturated soil are the key parameters in the quantitative modeling of water flow and solute transport in the vadose zone,which can be predicted by the pore network model.The major advantages of the pore network model are the direct and exact representation of the pore space topology and the pore-scale modeling of transport phenomena in soil.In recent years,the considerable progresses have been made in the image acquisition and processing,the pore network generation and the numerical solution techniques of the pore-scale models.The recent advances in pore network modeling in the vadose hydrology are reviewed,and the problems and the future development of this technique are also discussed.