Land Surface Modeling With Enhanced Considerations Of Soil Evaporation And Coupled Transport Of Soil Moisture And Heat

Land surface process include water, energy and momentum exchange which happened between land surface and atmosphere. Soil Evaporation is one of the main processes in land-atmosphere exchange. It is not only the constituent of energy balance but the constituent of water balance in the land surface. The simultaneous exist of water potential and temperature gravity can induce energy and moisture transport at the same time. The study of soil evaporation and coupled transport of soil moisture and heat is very important in land surface and climate modeling.The first part of this dissertation is introduction. Firstly, the paper discusses the background and significance of the research. Then it introduces the development of land surface model simply. After that, the thesis overviews the research on soil evaporation, coupled transport of soil moisture and heat, and soil hydraulic and thermal characteristics. Afterwards, it put forwards the main problem that the study faced, and the problem that the dissertation will solved. At last, it explains the research method, structure and creative point of the thesis.The second part of this dissertation discusses the research method and process of the soil evaporation model. At first, it discusses the background and theoretical basis of the research of soil evaporation. Then it pictures the process to build soil evaporation model at length. The core idea of the development of the new model is that it incorporates soil surface evaporation with soil inner vapor diffusion. The next part is result validation. The experimental data source is HEIFE land surface experiment. After coupled the newly development soil evaporation model with the CoLM land surface model, the result before and after CoLM model modification are compared with the observational result. The comparative result indicates that the model after modification by this paper can simulate soil evaporation better. The third part of the paper studies the coupled transport model of soil moisture and heat.In the first place, it depicts the background and theoretical basis of the study. Then the coupled transport model is developed and coupled with the CoLM model. At last, through the comparison with the experimental dataset, the thesis compares and analyses the newly developed soil evaporation model and coupled transport model in detail. At last, the physical process of soil evaporation and moisture and heat transport are analyzed.The last part of this dissertation summarizes the main conclusions and puts forward the assumptions for further study.