INTRODUCTION:

1, According to the statement ---> According to this statement 

2, However, the flow in porous media is actually a two-phase flow problem, which needs complicated...

    　　　　　　　　　　　　　　　　　　　　　　　　----->    problem, that needs ...

3, ....by nonlinearities, moisture retention hysteresis, soil heterogeneity, as well as multiple length and time scales....

                                                                              　　　　      ----->  ..........., as well as bymultiple length...

4, Although successful applications of this assumption has been shown in most cases, there are somesituations where the air phase can significantly retard or speed up the infiltration.

 ----->  Although successful application of this assumption has been demonstrated in many cases, there are situations where the air phase can significantly retard or speed up infiltration.

5, ...continuous efforts in building...   ----->  ...continuous efforts to build...

6. At present, there exist several two-phase flow and transport models, which have overcome most of the above mentioned difficulties.

 ----->  At present, several two-phase flow and transport models exist , that have overcome most of the above mentioned difficulties.

7. Recently, based on......, Niessner and Hassanizadeh presented...

 ----->  Based on..., Niessner and Hassanizadeh recently presented...

8, Furthermore, in order to build rigorous multiphase models, thermodynamically constrained averaging theory approach is developed for modeling flow and transport phenomena in porous medium systems.

 -----> Furthermore, in order to build rigorous multiphase models, a thermodynamically constrained averaging theory approach was developed to model flow and transport phenomena in porous medium systems.

9, In these works, although the weakness of classical, empirical approaches were discussed systematically, it is not easy to get an illustrative picture on the differences between a two-phase heat and mass flow model and the traditional unsaturated soil moisture and heat flow model.

-----> Although the weaknesses of classical, empirical approaches are discussed systematically in these papers, it is not easy to form an illustrative picture of the differences between a two-phase heat and mass flow model and the traditional unsaturated soil moisture and heat flow model.

10. The latter model is still widely used in many unsaturated flow simulators, which is subsequently adopted as the sub-model in the hydrological integration models.

-----> The latter model is still widely used in many unsaturated flow simulators, and subsequently adopted as sub-model in hydrological integration models.

11. Furthermore, to estimate soil moisture dynamics using remote sensing data, most of the land surface models (LSM) consider the soil moisture transport without using two-phase flow approaches.

----->Furthermore, to estimate soil moisture dynamics using remote sensing data, most land surface models (LSMs) do not base soil moisture transport on two-phase flow approaches.

12. There is a need to elucidate mechanically how the traditional coupled moisture and heat flow model can be improved when a two-phase flow approach is applied.

----->There is a need to elucidate mechanically how the traditional coupled moisture and heat flow model can be improved by applying a two-phase flow approach.

13. To achieve this purpose, we present a two-phase heat and mass flow model considering diffusion, convection and dispersion mechanisms, in which Milly’s matric head-based equations were adopted as the basis for the mass balance equation of soil moisture. 

----->To achieve this, a two-phase heat and mass flow model is presented, considering diffusion, convection and dispersion mechanisms in which Milly’s matric head-based equations are adopted as the basis for a mass balance equation of soil moisture.

14. In addition to existing mechanisms included in Milly’s model, the effects of thermal liquid flux, andthe effects due to considering dry air phase (dispersive vapor flux, and vapor flux as part of the bulk flow of dry air) were considered.

----->In addition to the existing mechanisms included in Milly’s model, the effects of the thermal liquid flux, as well as the effects of the dry air phase (dispersive vapor flux, and vapor flux as part of the bulk flow of dry air) are considered.

15. In this way, the differences between the traditional coupled moisture and heat flow model and the new two-phase heat and mass flow model will be identified during the formulation development.

----->This way, the differences between the traditional, coupled moisture and heat flow model and the new, two-phase heat and mass flow model become evident as the formulation is developed.

16. The mass balance equation for dry air includes both bulk flow of dry air and the air dissolved in the liquid.

----->The mass balance equation for dry air includes both the bulk flow of dry air and the air dissolved inliquid. 

17. The full range of conduction, convection, dispersion, latent heat of vaporization, and the differential heat of wetting were covered in the energy balance equation, in which the differential heat of wetting is the amount of heat released when a small amount of free water is added to the soil matrix. 

-----> The full range of conduction, convection, dispersion, latent heat of vaporization, and differential heat of wetting is represented in the energy balance equation. The differential heat of wetting is the amount of heat released when a small amount of free water is added to the soil matrix.

18. Based on the balance equations of moisture, dry air, and energy, three coupled partial differential equations were solved simultaneously using the Galerkin residual finite element method with various boundary and initial conditions.

-----> Based on the balance equations of moisture, dry air, and energy, three coupled partial differential equations are solved simultaneously using the Galerkin residual finite element method with various boundary and initial conditions.

19. The validation of the new model was attempted in two steps. First, the capacity of describing the two-phase flow under isothermal condition was investigated using the infiltration experiments by Touma and Vauclin. Second, the verification of the traditional coupled heat and mass flow under constant air pressure was carried out by comparing simulation results to the analytical results in Milly’s research.

-----> Validation of the new model is attempted in two steps. Firstly, the capacity to describe the two-phase flow under isothermal conditions is investigated, based on the infiltration experiments by Touma and Vauclin. Secondly, the traditional coupled heat and mass flow under constant air pressure is verified, comparing the simulation results with the analytical results in Milly’s  research. 

20. In section 2, we discuss how the new model is developed by taking diffusion, convection and dispersion mechanisms into account, with a basis on the traditional coupled moisture and heat flow model. 

----->In Section 2, development of the new model is discussed, taking diffusion, convection and dispersion mechanisms into account, based on the traditional coupled moisture and heat flow model.

21. Next, in section 3, the benchmark numerical tests and numerical modeling study are carried out. Results of numerical simulations are presented to illuminate the significance of the inclusion of air phase effect in the traditional coupled mass and heat transfer and the inclusion of temperature effectin isothermal two-phase flow (air-water flow). The conclusions are drawn in section 4.

-----> In Section 3, benchmark numerical tests and a numerical modeling study are carried out. Results of the numerical simulations are presented to illuminate the significance of including the air phase effect in the traditional coupled mass and heat transfer, and of including the temperature effect in the isothermal two-phase flow (air-water flow). Conclusions are presented in Section 4.