Partitioning of eddy covariance flux measurements is routinely done to quantify the contributions of separate processes to the overall fluxes. Measurements of carbon dioxide fluxes represent the difference between gross ecosystem photosynthesis and total respiration, while measurements of water vapor fluxes represent the sum of transpiration and direct evaporation. Existing flux partitioning pr...

to diffuisive and turbulent vapor flux in the external air, a similar diffusive resistance which results from the internal leaf geometry, inclusive of the stomlata, and1 parallel to the latter, a resistance to vapor diffusion1 throu-gh the cuticle. In contrast. the last 2 resistances do not exist in the evaporation froml an open water sturface or a moist blotter paper. The resistanice in these ...

Plants respond to many environmental changes by rapidly adjusting their hydraulic conductivity and transpiration rate, thereby optimizing water-use efficiency and preventing damage due to low water potential. A multiple-load-cell apparatus, time-series analysis of the measured data, and residual low-pass filtering methods were used to monitor continuously and analyse transpiration of potted tom...

estimation of evapo-transpiration is necessary in cases such as irrigation planning, determining of evaporation of the water bodies, water balance assessment, estimation of runoff and watershed management and ecological and meteorological studies. evapo-transpiration can be determined precisely using field measurements. however, these methods provide evapo-transpiration just for limited areas f...

Soil moisture simulation in current landsurface schemes is diverse: in terms of the realism (and complexity) of the parameterizations and in terms of the resulting predictions. Even after careful adjustment, the range in soil moisture among the results from the 14 schemes compared for the HAPEX-MOBILHY (S. France) site's 1.6 m soil layer remains around 100 mm (the annual precipitation for HAPEX...

Full coupling of physical processes, natural numerical coupling, and parsimonious but accurate data coupling are three key steps in efficient and accurate simulation of distributed hydrologic states in watersheds. Here we present a physically-based, spatially distributed hydrologic model (called PIHM) that utilizes all the three coupling strategies. Interception, snow melt, transpiration, evapo...

This paper focuses on the quantification of the green – vegetation related – water flux of forest stands in the temperate lowland of Flanders. The underlying reason of the research was to develop a methodology for assessing the impact of forests on the hydrologic cycle in comparison to agriculture. The tested approach for calculating the water use by forests was based on the application of the ...

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...

Using a fully coupled climate–terrestrial ecosystem model, we demonstrate explicitly that an initial perturbation on vegetation induces not only a direct positive vegetation feedback, but also a significant indirect vegetation–soil moisture feedback. The indirect feedback is generated through either fractional cover change or soil moisture depletion. Both indirect feedback mechanisms are trigge...