Details

Autor(en) / Beteiligte

• Li, Wanxin
• Brunner, Philip
• Hendricks Franssen, Harrie-Jan
• Li, Zhi
• Wang, Zhoufeng
• Zhang, Zhengyu
• Wang, Wenke

Titel

Potential evaporation dynamics over saturated bare soil and an open water surface

Ist Teil von

• Journal of hydrology (Amsterdam), 2020-11, Vol.590, p.125140, Article 125140

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals

Beschreibungen/Notizen

• •A unique lysimeter experiment was conducted in a semi-arid region to compare the potential evaporation rate from saturated bare soil and water in summer.•Potential evaporation rate from saturated bare soil is higher than water, which is related to the difference in thermal properties between soil and water.•Results can be explained by the energy balance considerations.•The measured potential evaporation rate is relatively well reproduced by energy balance, Penman-Monteith and Priestly-Taylor equations. Actual evaporation (Ea) can be calculated as a fraction of potential evaporation (PE), which refers to the evaporation rate if supply water is unlimited. Potential evaporation depends on the available energy and the underlying material, and different approaches to estimate potential evaporation exist nowadays. This study provides a detailed analysis of the evaporation dynamics over fully saturated, sandy soil (PEs) and an open water surface (PEw). Moreover, the performance of commonly used methods to estimate PE is assessed. At the basis of these analyses is a lysimeter experiment in the Guanzhong Basin, China, which allowed a precise measurement of PE with a very high temporal resolution. Temperature profiles in lysimeters and meteorological data were also measured during the experiment. A comparison of PEs and PEw was carried out for seven consecutive days (August 11th to 17th, 2016). Results show that PEw is smaller than PEs on a daily scale, with PEw rates being bigger than PEs at night but smaller during daytime. Furthermore, the temporal dynamics of PEw lags 4–5 h behind PEs. In accordance with the energy balance equation, PE dynamics are mainly governed by “available energy”. The PE rates calculated by Penman-Monteith (PM) and Priestly-Taylor (PT) based on these measurements were also evaluated. The measured PE is relatively well reproduced by PM and PT equations. Finally, the effect of using different approaches to estimate PE on calculating Ea was tested by an integrated hydrological model that calculates water flow in the unsaturated zone by solving the Richards equation. The relative differences were up to 17.5%.