Integrated modelling of the soil–water–atmosphere–plant system using the model SWAP 2·0 an overview of theory and an application

Kroes, J.G.; Wesseling, J.G.; Dam, J.C. van

doi:10.1002/1099-1085(20000815/30)14:11/12<1993::aid-hyp50>3.0.co;2-#

Cited by 101 publications

(55 citation statements)

References 5 publications

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“…Two methods to assess surface-soil moisture were explored. The first method was based on ground-penetrating radar and the second on a hydrological model, the soil, water, atmosphere and plant (SWAP) model [65], with which the surface-soil moisture level can be estimated as a function of time. The latter method was tested with two types of input meteorological data: ground meteorological data and estimated meteorological data.…”

Section: Discussionmentioning

confidence: 99%

Maize Leaf Area Index Retrieval from Synthetic Quad Pol SAR Time Series Using the Water Cloud Model

et al. 2015

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Abstract:In order to monitor crop growth along the season with synthetic aperture radar (SAR) images, radiative transfer models were developed to retrieve key biophysical parameters, such as the Leaf Area Index (LAI). The semi-empirical water cloud model (WCM) can be used to estimate LAI values from SAR data and surface soil moisture information. Nevertheless, instability problems can occur during the model calibration, which subsequently reduce its transferability in both time and space. To avoid these ill-posed cases, three calibration methodologies are benchmarked in the present study. The accuracy of the retrieved LAI values for each methodology was analyzed, as well as the sensitivity of the signal to LAI for different soil moisture values. The sensitivity of the cross-polarization was highlighted especially for high LAI. The VV polarization was found sensitive for LAI values inferior to 2 m 2 /m 2 . Given the differential sensitivity of the C-band backscatter to maize canopies in each polarization, a Bayesian fusion of the LAI estimates in linear polarizations was developed. This fusion gives lower weights to estimates with a high uncertainty. This method systematically reduces the error and its associated variance. When considering all polarizations, the RMSE on LAI estimation decreased by 0.32 m 2 /m 2 , i.e., one fourth of the error value, as compared to the best estimation from a single polarization, and the associated uncertainty was reduced by a factor of two. Focusing on the two most sensitive polarizations to maize canopies (VV-HV), the error diminished by a third. This fusion framework shows thus a great potential to improve the accuracy and reliability of LAI retrieval of C-band quad-polarized data, as well as dual-polarized data, such as Sentinel-1.

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Section: Discussionmentioning

confidence: 99%

Maize Leaf Area Index Retrieval from Synthetic Quad Pol SAR Time Series Using the Water Cloud Model

et al. 2015

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“…SWAP (Soil-Water-Atmosphere-Plant) is a one-dimensional physically based model for water, heat and solute transport in variably saturated soil, and includes modules to simulate irrigation and crop growth (Kroes et al, 2000). SWAP simulates the vertical soil water flow and solute transport in close interaction with crop growth.…”

Section: The Agro-hydrological Swap Modelmentioning

confidence: 99%

Estimation of actual evapotranspiration of Mediterranean perennial crops by means of remote-sensing based surface energy balance models

Minacapilli

Agnese

Blanda

et al. 2009

Hydrol. Earth Syst. Sci.

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Abstract. Actual evapotranspiration from typical Mediterranean crops has been assessed in a Sicilian study area by using surface energy balance (SEB) and soil-water balance models. Both modelling approaches use remotely sensed data to estimate evapotranspiration fluxes in a spatially distributed way. The first approach exploits visible (VIS), nearinfrared (NIR) and thermal (TIR) observations to solve the surface energy balance equation whereas the soil-water balance model uses only VIS-NIR data to detect the spatial variability of crop parameters. Considering that the study area is characterized by typical spatially sparse Mediterranean vegetation, i.e. olive, citrus and vineyards, alternating bare soil and canopy, we focused the attention on the main conceptual differences between one-source and two-sources energy balance models. Two different models have been tested: the widely used one-source SEBAL model, where soil and vegetation are considered as the sole source (mostly appropriate in the case of uniform vegetation coverage) and the twosources TSEB model, where soil and vegetation components of the surface energy balance are treated separately. Actual evapotranspiration estimates by means of the two surface energy balance models have been compared vs. the outputs of the agro-hydrological SWAP model, which was applied in a spatially distributed way to simulate one-dimensional water flow in the soil-plant-atmosphere continuum. Remote sensing data in the VIS and NIR spectral ranges have been used to infer spatially distributed vegetation parameters needed to Airborne hyperspectral data acquired during a NERC (Natural Environment Research Council, UK) campaign in 2005 have been used. The results of this investigation seem to prove a slightly better agreement between SWAP and TSEB for some fields of the study area. Further investigations are programmed in order to confirm these indications.

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“…This allows for the simulation of numerous applied hydro-geochemical environmental engineering problems where mineral reactions have an important influence on the physical properties of partially saturated soils. Possible applications include vadose zone biodegradation processes [31,32], water management practices and irrigation techniques in arid and semiarid areas [33][34][35], salinity management [36][37][38][39] and the assessment of the longterm performance of reactive barriers [40][41][42][43][44][45][46]. Below, we present the theoretical model derivation followed by applications of the model to the case of kinetic halite dissolution in different moisture conditions and calcite precipitation due to cation exchange.…”

Section: Fig 1 Near Herementioning

confidence: 99%

Effect of mineral reactions on the hydraulic properties of unsaturated soils: Model development and application

Wissmeier

Barry

2009

Advances in Water Resources

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT AbsThe selective radius shift model was used to relate changes in mineral volume due to precipitation/dissolution reactions to changes in hydraulic properties affecting flow in porous media. The model accounts for (i) precipitation/dissolution taking place only in the water-filled part of the pore space and further that (ii) the amount of mineral precipitation/dissolution within a pore depends on the local pore volume. The pore bundle concept was used to connect pore-scale changes to macroscopic soil hydraulic properties. Precipitation/dissolution induces changes in the pore radii of water-filled pores and, consequently, in the effective porosity. In a time step of the numerical model, mineral reactions lead to a discontinuous pore-size distribution because only the water-filled pores are affected. The pore-size distribution is converted back to a soil moisture characteristic function to which a new water retention curve is fitted under physically plausible constraints. The model equations were derived for the commonly used van Genuchten/Mualem hydraulic properties. Together with a mixed-form solution of Richards' equation for aqueous phase flow, the model was implemented into the geochemical modelling framework PHREEQC, thereby making available PHREEQC's comprehensive geochemical reactions. Example applications include kinetic halite dissolution and calcite precipitation as a consequence of cation exchange. These applications showed marked changes in the soil's hydraulic properties due to mineral precipitation/dissolution and the dependency of these changes on water contents. The simulations also revealed the strong influence of the degree of saturation on the development of the saturated hydraulic conductivity through its quadratic dependency on the van Genuchten parameter . Furthermore, it was shown that the unsaturated hydraulic conductivity at fixed reduced water content can even r tract increase du ing precipitation due to changes in the pore-size distribution.

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Integrated modelling of the soil–water–atmosphere–plant system using the model SWAP 2·0 an overview of theory and an application

Cited by 101 publications

References 5 publications

Maize Leaf Area Index Retrieval from Synthetic Quad Pol SAR Time Series Using the Water Cloud Model

Maize Leaf Area Index Retrieval from Synthetic Quad Pol SAR Time Series Using the Water Cloud Model

Estimation of actual evapotranspiration of Mediterranean perennial crops by means of remote-sensing based surface energy balance models

Effect of mineral reactions on the hydraulic properties of unsaturated soils: Model development and application

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