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, ...

This paper describes the application of a continuous daily water balance model called SWAT(Soil and Water Assessment Tool) for the conterminous U.S. The local water balance is represented by four control volumes; (1) snow, (2) soil profile, (3) shallow aquifer, and (4) deep aquifer. The components of the water balance are simulated using "storage" models and readily available input parameters. ...

the determination of soil wetting front which caused by emitters is one of the important issues in designing trickle irrigation system. in this study, a mathematical model introduced in order to study the position of soil wetting front during irrigation by point emitters in homegenious soil in unsteady condition. the model solves governing differential equation of unsaturated flow in cylindrica...

A simple soil–vegetation–atmosphere transfer (SVAT) model designed for scaling applications and remote sensing utilization will be presented. The study is part of the Semi-Arid Land Surface Atmosphere (SALSA) program. The model is built with a single-bucket and single-source representation with a bulk surface of mixed vegetation and soil cover and a single soil reservoir. Classical atmospheric ...

[1] The terrestrial Arctic water cycle is strongly influenced by the presence of permafrost, which is at present degrading as a result of warming. In this study, we describe improvements to the representation of processes in the pan-Arctic Water Balance Model (PWBM) and evaluate simulated soil temperature at four sites in Alaska and active-layer thickness (ALT) across the pan-Arctic drainage ba...

A two-layer model for 1D vertical unsaturated flow based on the hypothesis of a sharp wetting front is presented. The model further assumes a uniform pore pressure throughout the wetting zone at any given time during the infiltration and redistribution processes. These assumptions allow to reduce the theoretical Richards equation to an ordinary differential equation that can track average soil ...

Soil water balance has response to climate change and evaluation of soil water change is one of the most important items of climate change impact assessment. GCM outputs under three scenarios were statistically downscaled during 2010~2039 to simulate the potential change of soil water balance in Wangdonggou watershed on the Loess Plateau with WEPP model. GCM predicted a 1.8 to 17.5% increase in...

Net ecosystem carbon exchange (NEE) was measured with eddy covariance method for two adjacent forests located at the southern boundary of European taiga in Russia in 1999–2004. The two spruce forests shared similar vegetation composition but differed in soil conditions. The wet spruce forest (WSF) possessed a thick peat layer (60 cm) with a high water table seasonally close to or above the soil...