Coupled dynamics in soil
Understanding the transport mechanisms of liquid water, water vapor, air pressure and heat by field experiments and numerical simulation
| Graduate student | Yijian Zeng |
| Promotors | Prof. Bob Su |
| Co-promotors | Prof. Li Wan, Prof. Jun Wen |
| Partner | |
| Timeline | January 2007 - February 2011 |
| Sources of funding |
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PhD thesis (4.36 MB) |
Soil moisture in unsaturated zone plays a critical role in the partitioning of precipitation into surface runoff, evaporation, and groundwater recharge. Simultaneously, soil moisture controls the conversion of incoming solar and atmospheric radiation into sensible, latent, and radiant heat losses by its transport in vapour phase (Fig. 1). Apart from solar radiation and soil nutrients, the availability of soil moisture is the key to plant growth and to the production of crops. As such, soil moisture is not only important to agriculture but may also potentially affect the global climate and is considered as a critical focus for global change studies.
Figure 1: Physical process related to soil moisture (From Fig. 1 in Krahn 2004).
The importance of soil moisture have resulted in a very large collection of numerical models, all of which simulate water transport both in liquid and vapour in uppermost soil layer. Such kind of flow in porous media is actually two-phase flow problem, where the gas phase transfer would be taken into account. It has been shown there are some situations where the air phase can significantly retard or speed up the infiltration.
Our research is trying to develop a two-phase mass and heat transport model with full consideration on diffusion, convection and dispersion mechanisms. With the developed model, we are going to identify the process of mass and heat transfer in unsaturated soil more mechanistically, which would be used subsequently in atmospheric models to provide a more realistic land surface process. Furthermore, considering regional scale problem, the remote sensing observation would be used as the surface driving forces for our model by data assimilation approach to get the soil moisture and temperature profiles. As a part of work to quantify the detailed coupled liquid, vapour and heat flow processes in the arid region in China, A field work was conducted in the Badain Jaran Desert from 31 May to 21 August 2008 (Fig. 2). If you feel interesting in our work, please contact us with the email address: Yijian@itc.nl, bob@itc.nl.
Figure 2: Field scale site in the Badain Jaran desert.
References
Zeng, Y., Li Wan, Su, Z. and ... [et al.] (2009) Diurnal soil water dynamics in the shallow vadose zone : field site of China University of Geosciences, China. In: Environmental geology : international journal of geosciences, 58 (2009)1, pp. 11-23. Full text | Full text
Zeng, Y., Su, Z. and ... [et al.] (2009) Diurnal pattern of the drying front in desert and its application for determining the effective infiltration. In: Hydrology and earth systems sciences (HESS), 13 (2009)6, pp. 703-714. Full text | Full text