Implications of climate change for evaporation from bare soils in a Mediterranean environment

Abstract

The purpose of this study was to predict quantitative changes in evaporation from bare soils in the Mediterranean climate region of Turkey in response to the projections of a regional climate model developed in Japan (hereafter RCM). Daily RCM data for the estimation of reference evapotranspiration (ETr) and soil evaporation were obtained for the periods of 1994--2003 and 2070--2079. Potential evaporation (Ep) from bare soils was calculated using the Penman-Monteith equation with a surface resistance of zero. Simulation of actual soil evaporation (Ea) was carried out using Aydin model (Aydin et al., Ecological Modelling 182:91-105, 2005) combined with Aydin and Uygur (2006, A model for estimating soil water potential of bare fields. In Proceedings of the 18th International Soil Meeting (ISM) on Soils Sustaining Life on Earth, Managing Soil and Technology, Sanliurfa, 477-480pp.) model of predicting soil water potential at the top surface layer of a bare soil, after performances of Aydin model (R2 = 94.0%) and Aydin and Uygur model (R2 = 97.6) were tested. The latter model is based on the relations among potential soil evaporation, hydraulic diffusivity, and soil wetness, with some simplified assumptions. Input parameters of the model are simple and easily obtainable such as climatic parameters used to compute the potential soil evaporation, average diffusivity for the drying soil, and volumetric water content at field capacity. The combination of Aydin and Aydin and Uygur models appeared to be useful in estimating water potential of soils and Ea from bare soils, with only a few parameters. Unlike ETr and Ep projected to increase by 92 and 69 mm (equivalent to 8.0 and 7.3% increases) due to the elevated evaporative demand of the atmosphere, respectively, Ea from bare soils is projected to reduce by 50 mm (equivalent to a 16.5% decrease) in response to a decrease in rainfall by 46% in the Mediterranean region of Turkey by the 2070s predicted by RCM, and consequently, to decreased soil wetness in the future.

Simulation of Soil Hydrological Components in Chuncheon over 30 years Using E-DiGOR Model

“…E p rates were lower than ET r values (E p =0.75×ET r ), because the evaporation from bare soils depended not only on the atmospheric conditions but also on soil properties. Aydin et al (2008) found a similar relationship between E p and ET r . Kroes et al (1999) reported that ET r rates could be multiplied by a coefficient value of 0.5 to 1.5 to obtain E p .…”

“…In order to overcome such problems, Aydin (2008) proposed an interactive way (called E-DiGOR 485 model by the author) for predicting daily actual soil evaporation, soil water storage and drainage rates, since these components are strongly interdependent. The applicability of E-DiGOR model to a wide range of environments has been tested by different researchers using field-based measurements (Aydin, 2008;Aydin et al, 2008;Kurt, 2011). Similarly, the model had been successfully applied to different environmental conditions in Turkey, Japan and Sri Lanka (Aydin et al, 2005;Onder et al, 2009;Aydin et al, 2012).…”

Evaporation Process in Soil Surface Containing Calcic Nodules on the Northern Loess Plateau of China by Simulated Experiments

“…Through evaporation, soil water comes into the atmosphere to form cloud, which is a significant source of atmospheric water. At the same time, soil evaporation can lead to soil water loss [1][2][3][4][5][6]. According to the estimation, this water loss can amount to 50% of the total soil water or more during a normal growing season [7,8].…”

“…First, calcic nodules can modify soil configuration and surface properties, leading to the changes of surface roughness and soil reflectivity that is closely linked to soil thermal property [12]. Second, calcic nodules have some effect on water allocation between soil and calcic nodules [12,13], and finally initiates soil moisture [1,2], which to some extent dominates soil evaporation [14]. In addition, calcic nodules can enhance soil water holding capacity and reduce water vapor sorption between soil surface and atmosphere especially as calcic nodules mulching soil surface [15].…”

“…Hence, it is urgently needed to quantify soil water loss caused by evaporation in order to further understand water cycle process, promote local vegetation restoration as well as filed water management. However, owing to difficulty in soil sampling and the limitation of water measurement methods, evaporation behavior in soil containing calcic nodules is still poorly understood [1,2].…”