EGU General Assembly 2020
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Evaporation over saturated bare soil: the role of soil texture

Wanxin Li1,2, Wenke Wang1,2, Philip Brunner3, Zhoufeng Wang1,2, Zhi Li4, Yike Wang1,2, Yanying Lu1,2, and Harrie-Jan Hendricks Franssen5
Wanxin Li et al.
  • 1Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Chang’an University, Ministry of Education, P. R. China
  • 2School of water and environment, Chang’an University, P. R. China
  • 3Center for Hydrogeology and Geothermics, (CHYN), Université de Neuchâtel, Switzerland
  • 4Xi’an Research Institute of China Coal Technology & Engineering Group Corp.
  • 5Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany

Calculating actual bare soil evaporation (ETa) on the basis of potential bare soil evaporation (PE) is a widely followed approach in many disciplines including hydrogeology, hydrology and agricultural sciences. This approach considers that PE is independent from soil properties, and only ETa is affected by soil properties. In this work, in a unique experiment, seasonal and diurnal cycles of PE over saturated bare soil were assessed for lysimeters installed in the Guanzhong Basin, China. The assessment was made for different soil textures including gravel (PEgravel), coarse sand (PEcoarse) and fine sand (PEfine) and also open water (PEwater). Meteorological variables, ground heat flux and soil temperature were captured at a high temporal resolution (5 min.) for more than 15 consecutive months. The daily evaporation rates over saturated bare soil (PEsoil) showed clear differences between gravel, coarse sand and fine sand, with higher PE for fine sand, smaller PE for coarse sand and smallest PE for gravel, during spring and summer. In addition, PEwater was smaller than PE for the saturated bare soil lysimeters. In autumn and winter, the measured PE rates over different surfaces showed only minor differences. The measurement data also revealed that during spring and summer night-time PE was considerable with ~1.0 mm ET per night. These results can be quantitatively explained with detailed calculations of the energy balance, considering the different porosities for gravel, coarse sand and fine sand, as well as the thermal conductivities of the phases which constitute the porous media. 

How to cite: Li, W., Wang, W., Brunner, P., Wang, Z., Li, Z., Wang, Y., Lu, Y., and Hendricks Franssen, H.-J.: Evaporation over saturated bare soil: the role of soil texture, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-412,, 2019

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Presentation version 2 – uploaded on 05 May 2020
the x axis in figure 2 is modified. there is a little mistake in previous version
  • CC1: Comment on EGU2020-412, Hamideh Nouri, 06 May 2020

    Interesting research. What type of lysimeter did you use? How long was the experiment? Was there any replication?

    • AC1: Reply to CC1, Wanxin Li, 06 May 2020

      In this research,we use large constant water-table type non-weighing lysimeter, using markov bottle to measure the PE rate. Continuous observation has last for 20 months.  To the best of our knowledge, our research is unique.

Presentation version 1 – uploaded on 04 May 2020 , no comments