The Effect of Salinity on Water Evaporation and the Associated Determinants

Abstract

【Objective】 Water evaporation is influenced by many factors, besides meteorological factors, salinity also has an important effect on it. The aim of this paper is to study its impact on water evaporation in coastal saline-alkali land. 【Method】 The experiment was conducted by setting a salinity gradient ranging from 1 to 20 g/L from May to October in 2018. Evaporation from water with different salinity was measured using a in-house 20 cm evaporation pan, and the correlation between meteorological factors and the evaporation was determined by gray relational analysis. 【Result】 ①Increasing water salinity increased water surface tension, thereby leading to a decrease in water evaporation. The cumulative evaporation with 1 g/L of saline water over the experimental period increased by 97.66 mm compared with that with 20 g/L of saline water. ②Evaporation was positively correlated with radiation intensity (R), wind speed (Ws), vapor pressure deficit (VPD), and air temperature (Ta), while negatively correlated with relative humidity (RH), atmospheric pressure (Pr) and Salinity (S). ③Among all factors we compared, R affected the evaporation from the coastal saline-alkali land more. We also found that Ws and VPD affected the evaporation on sunny and cloudy days. 【Conclusion】 Increase in water salinity increased water surface tension, resulting in a decrease in water evaporation. Compared with water salinity, the meteorological factors affected the evaporation more, especially the radiation intensity.

Keywords

• evaporation
• saline water
• meteorological factors
• gray relational analysis
• path analysis