estimated effective precipitation (pe) in dryland areas is an essential element of water resource management. itrepresents the amount of precipitation available in the crop root zone to meet the needs of evapotranspiration. thecurrent study compared different approaches for estimating pe in different climatic zones of iran. a two-layer soil–water balance (swb) model was adopted based on the pro...

This study evaluates seven evapotranspiration models and their performance in water balance studies by using lysimeter measurement data at the Mönchengladbach hydrological and meteorological station in Germany. Of the seven evapotranspiration models evaluated, three models calculate actual evapotranspiration directly using the complementary relationship approach, i.e. the CRAE model of Morton, ...

The main goal of this research was to estimate the actual evapotranspiration (ETc) of a drip-irrigated apple orchard located in the semi-arid region of Talca Valley (Chile) using a remote sensing-based soil water balance model. The methodology to estimate ETc is a modified version of the Food and Agriculture Organization of the United Nations (FAO) dual crop coefficient approach, in which the b...

Water shortage is a serious constraint on crop production on the North China Plain (NCP), where cropland is mainly irrigated by pumping groundwater from alluvial aquifers. To develop a sustainable ground water and irrigation management strategy, we developed a three-layer soil water balance model which is easy to use, robust, but physically based simulation tool. The model successfully simulate...

The description of soil moisture dynamics is a challenging problem for the hydrological community, as it is governed by complex interactions between climate, soil and vegetation. Recent research has achieved significant advances in the description of temporal dynamics of soil water balance through the use of a stochastic differential equation proposed by Laio et al. (2001). The assumptions of t...

Vapor movement is often an important part in the total water flux in the vadose zone of arid or semiarid regions because the soil moisture is relatively low. The twomajor objectives of this study were to develop a numerical model in the HYDRUS-1D code that (i) solves the coupled equations governing liquid water, water vapor, and heat transport, together with the surface water and energy balance...

Management and irrigation of plants increasingly relies on accurate mathematical models for the movement of water within unsaturated soils. Current models often use values for water content and soil parameters that are averaged over the soil profile. However, many applications require models to more accurately represent the soil–plant–atmosphere continuum, in particular, water movement and satu...

Using a stochastic differential equation (SDE) approach, we examine the dynamics of the continental-scale water balance in the central United States. Whitenoise and colored-noise versions of the model are developed based on analysis of atmospheric data from the National Center for Environmental Prediction (NCEP) reanalysis project and long-term records of precipitation and soil moisture. Improv...

Climate change is generally predicted to increase net primary production, which could lead to additional C input to soil. In arid central Asia, precipitation has increased and is predicted to increase further. To assess the combined effects of these changes on soil CO2 efflux in arid land, a two factorial manipulation experiment in the shrubland of an arid region in northwest China was conducte...

A one-dimensional soil model has been developed to better predict heat and water exchanges in arid and semiarid regions. New schemes to calculate evaporation and adsorption in the soil were incorporated in the model. High performance of the model was confirmed by comparison of predicted surface fluxes, soil temperature, and volumetric soil water content with those measured in the Negev Desert, ...