Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Systeemstap naar minimaal energieverbruik Alstroemeria : metingen op praktijkbedrijven en een energiezuinige teeltconcept
Garcia Victoria, N. ; Zwart, Feije de; Weel, Peter van; Steenhuizen, Johan ; Groot, Marco de - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1372) - 66
kasgewassen - glastuinbouw - kastechniek - kassen - alstroemeria - energiebehoeften - energiebesparing - verwarming - aanvullend licht - kunstlicht - simulatiemodellen - isolatie (insulation) - evaporatie - greenhouse crops - greenhouse horticulture - greenhouse technology - greenhouses - energy requirements - energy saving - heating - supplementary light - artificial light - simulation models - insulation - evaporation
Alstroemeria cultivation in The Netherlands requires energy for heating, supplementary light and root cooling. For the program “Greenhouse as Source of Energy” we calculated to which extent the energy demand for growing this crop can be reduced with existing energy saving innovations. Some innovations were tested in practice, others were calculated by means of the greenhouse climate simulation model Kaspro. Results showed that it is possible to save up to 34% energy for heating compared to the reference situation. 40% energy can be saved on electricity for supplementary light and root cooling. However, this strategy leads to a reduced amount of PAR-light in the winter, and 4% less flowers in comparison with the reference. The greatest impact can be achieved by increasing the insulation of the greenhouse by using double screens, reducing the evaporation from the soil, improving the crop hygiene to avoid extra evaporation from crop debris and reduce pest pressure, and implementing controlled dehumidification of the greenhouse air.
Indampen van dunne mestfracties in combinatie met een luchtwasser
Hoeksma, P. ; Hol, A. ; Verheijen, R. ; Verdoes, N. - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1014) - 25
vloeibare meststoffen - drijfmest - evaporatie - reinigers - ammoniakemissie - varkenshouderij - liquid manures - slurries - evaporation - scrubbers - ammonia emission - pig farming
The effect of an evaporator/air-scrubber combination on the reduction of ammonia and odour was evaluated and the evaporation capacity was assessed. It was concluded that at pig farms substantial reduction (one third) of the slurry volume can cost effectively be achieved while maintaining ammonia and odour reduction effiency.
Snijbloemen telen bij hoge RV met behoud van kwaliteit : literatuuronderzoek in opdracht van Kas als Energiebron
Garcia Victoria, Nieves ; Slootweg, Casper ; Marissen, Nollie - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1410) - 58
snijbloemen - glastuinbouw - kasgewassen - kassen - relatieve vochtigheid - evaporatie - vaasleven - huidmondjes - literatuuroverzichten - cut flowers - greenhouse horticulture - greenhouse crops - greenhouses - relative humidity - evaporation - vase life - stomata - literature reviews
Om CO2 voor de fotosynthese naar het blad te leiden, hebben planten huidmondjes. Via de open huidmondjes verdampt water. De plant reguleert de opening en sluiting van huidmondjes, en dus haar waterhuishouding, aan de hand van prikkels uit de omgeving (water, CO2, licht). Snijbloemen verliezen na de oogst water door verdamping wat weer aangevuld moet worden via de steel met het vaaswater. Bij goed functionerende huidmondjes is die verdamping beperkt, maar de huidmondjes van snijbloemen die geteeld zijn bij aanhoudend hoge RV zijn anatomisch en fysiologisch anders: ze zijn ongevoelig voor sluitingsprikkels, waardoor ze in de vaas sterk door blijven verdampen. Dit leidt tot een korter vaasleven omdat de wateropname door de afgesneden steel beperkend wordt. Het ontbreken van een donkerperiode tijdens de teelt leidt ook tot niet-functionele huidmondjes. Als er gedurende de ontwikkeling regelmatig een sluitings-prikkel wordt gegeven, blijven huidmondjes functioneel. Dit zou gerealiseerd kunnen worden door het hanteren van een donker-periode in combinatie met een voldoende lage RV, periodieke verlagingen van de RV tijdens de teelt, de teelttemperatuur ’s nachts verhogen (waarmee de RV daalt), of een sterke luchtbeweging (kortstondig ingezet). Groen (LED) licht aan het begin van de nachtperiode en het gebruik van schermen tegen uitstraling kunnen wellicht ook de huidmondjes functionaliteit positief beïnvloeden, maar daar is nog onvoldoende over bekend. Het Nieuwe Telen is er sterk op gericht om de huidmondjes open te houden voor maximale fotosynthese en productie door, onder andere, het handhaven van een hoge RV. Bij producten die geen last hebben van waterverlies na de oogst, zoals vruchtgroenten leidt het tot zeer goede productie en kwaliteit met weinig inzet van energie. Het Nieuwe Telen is sterk in ontwikkeling. Bij het vertalen van Het Nieuwe Telen naar bladhoudende snijbloemen dient er ruimte te worden gemaakt voor een regelmatig terugkomende trigger om de huidmondjes te laten sluiten wil het succesvol toegepast kunnen worden.
Een nieuwe en handzame lysimeter: eerste stap naar een nationaal netwerk voor de werkelijke verdamping?
Voortman, Bernard ; Witte, J.P. ; Rheenen, Hans van; Bosveld, F. ; Elbers, J.A. ; Bolt, F.J.E. van der; Heijkers, J. ; Hoogendoorn, Jan ; Bolman, A. ; Spek, T. ; Voogt, M. - \ 2016
Stromingen : vakblad voor hydrologen 22 (2016)2. - ISSN 1382-6069 - p. 49 - 63.
hydrologie - neerslag - waterbalans - grondwater - lysimeters - evaporatie - hydrology - precipitation - water balance - groundwater - evaporation
Vrijwel overal op aarde verdampt meer dan de helft van het neerslagwater, ook in Nederland. Toch wordt deze grote verliespost in ons land slechts sporadisch gemeten. Door inspanningen van kennisinstituten, bedrijven en overheid is daarom een lysimeter ontwikkeld. Metingen in 2014 en 2015 op twee locaties vertonen opvallende verschillen, maar ook grote overeenkomsten, met eddy-correlatiemetingen. Schattingen van de verdamping via satellietdata zijn hoger dan de metingen. Tijd daarom, om metingen in het veld te combineren met modellen en waarnemingen vanuit de ruimte
Telen met gestuurde vochtafvoer : komkommers in de Venlow Energy kas
Gelder, A. de - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1408)
teelt onder bescherming - kasgewassen - glasgroenten - glastuinbouw - dubbele beglazing - komkommers - cucumis sativus - evaporatie - ventilatie - vochtigheid - protected cultivation - greenhouse crops - greenhouse vegetables - greenhouse horticulture - double glazing - cucumbers - evaporation - ventilation - humidity
Funded by Kas als Energiebron, Wageningen UR Greenhouse Horticulture conducted an experiment witth cucumber in the Venlow Energy greenhouse with a high-wire system. The objective was to achieve a minimal evaporation during cultivation under double glazing and a film screen. In the night the evaporation fell to 15-25 g. m-2.hour-1. This was enough to grow cucumbers without deficiency symptoms. Only in March, some degree of “bolblad” occurred, but after a few sunny days the crop well recovered. The film screen was kept closed until 2 hours after sunset and one hour before sundown closed. This provided no problems for cultivation. In the night the humidity could rise above 95% without Mycosphearella problems. For the new cultivation strategy this means if other factors such as horizontal uniformity of the climate are good that cultivation in high humidity and with minimal ventilation is possible. For the Venlow Energy greenhouse ventilation rate was 0.37 and this delivers in winter conditions a sufficient degree of natural ventilation and moisture management.
Deep frying : from mechanisms to product quality
Koerten, K.N. van - \ 2016
University. Promotor(en): Maarten Schutyser, co-promotor(en): Remko Boom. - Wageningen : Wageningen University - ISBN 9789462576476 - 119 p.
deep fat frying - quality - chips (french fries) - evaporation - crusts - moisture meters - fried foods - crisps - frituren - kwaliteit - patates frites - evaporatie - korsten - vochtmeters - gebakken voedsel - aardappelchips

Deep frying is one of the most used methods in the food processing industry. Though practically any food can be fried, French fries are probably the most well-known deep fried products. The popularity of French fries stems from their unique taste and texture, a crispy outside with a mealy soft interior, but also because of the ease and speed of preparation. However, despite being a practical and easy method, the fundamental phenomena that occur during frying are very complex. This thesis aimed at gaining a deeper understanding of the frying of French fries. This was done at the product level, with regards to heat transfer, moisture loss, oil uptake and crust formation, and at the process level, which encompasses the oil movement in a frying unit and the consequent oil-fry interactions.

Firstly a numerical model was developed to describe the water evaporation during frying (Chapter 2). Though various models exist for describing moisture loss, they all use constant values for the heat transfer coefficient. However, the heat transfer coefficient actually varies greatly due to the varying degrees of turbulence, induced by the vapour bubbles escaping from the fry surface. Therefore, the model in this thesis incorporated an evaporation rate dependent heat transfer coefficient. Other than the varying heat transfer coefficient, the model was heat transfer dependent, with a sharp moving evaporation boundary and Darcy flow describing the flow of water vapour through the crust. The model was successfully validated against experimental results for moisture loss and temperature profiles in the fry.

For oil uptake during frying, a pore inactivation model from membrane technology was adopted (Chapter 3). In membranes, pores will inactivate when the transmembrane pressure becomes too low. In fries, this can be translated as pores in the crust inactivating when the evaporation rate becomes too low. As pores stop expelling water vapour, oil can migrate into the fry. The model also took into account the lengthening of the pores with increasing crust thickness, allowing for more oil uptake in inactivated pores. The model fitted well with experimental data for oil uptake during frying. Also, the pore inactivation model better described oil uptake during the initial stages of frying, where the evaporation rate is still relatively high, compared to the linear relation between oil uptake and moisture content, which is usually assumed in literature.

Both the influences of frying temperature and moisture content on crust structure and consequent textural properties were studied (Chapter 4). The crust structure was visualized and quantified using X-ray tomography (XRT), which uses multiple 2D X-ray pictures of a rotated sample to reconstruct a 3D density map. Textural properties, like hardness and crispness, were quantified using force deformation curves from a texture analyser. Moisture loss was shown to greatly increase porosity and pore size in fries. More crispy behaviour was also shown for higher moisture loss, though not significantly at moisture contents close to the initial moisture content. Though increased frying temperatures also showed an increased porosity and pore size, there was no significantly observed increase in crispness. This is most likely because the texture analysis was not sensitive enough to discern any increased crispness for porosities below a certain degree. Strikingly, for frying temperature around 195 °C, a decrease in crispness was observed. These samples visually also showed more plastic behavior. The most likely cause for this is degradation of sucrose, which happens around 186 °C, and consequent caramelization of glucose, thus increasing the glass transition temperature.

At the process level, oil flow and fry quality distribution were investigated using a pilot scale cross-flow fryer (Chapter 5). Oil circulation velocities were varied to observe the initial fluidization behavior of the fry bed through an observation window. This fluidization behavior was well described by the Ergun equation, modified for non-spherical particles. The distribution in moisture content of the fries was used as an indicator for quality distribution. Though increased oil circulation initially increased the homogeneity of the moisture content, upon fluidization the homogeneity actually decreased. Image analysis of fries before and after frying showed local packing of fries around their fluidization point. This was due to the non-spherical shape of the fries, making them more sensitive to channelling.

The results obtained in this thesis were finally discussed, together with the possibility to also model the process scale of the frying process (Chapter 6). The possibility of modelling the oil flow through a packed bed of fries, and the free-convective heat transfer during frying, using a CFD software package (STARCCM+) was shown. Additionally, the possibility of linking oil flows computed using CFD to the general models developed in this thesis was discussed. Modelling the momentum transfer of the expelled vapour bubbles to the oil, but also the movement of the fries themselves is still a faraway goal. However, a multiphase model that can describe both the entire frying setup as the consequent individual fry parameters would be invaluable.

Hoeveel water verdampt de stad?
Jacobs, C.M.J. ; Elbers, J.A. ; Moors, E.J. ; Hove, L.W.A. van - \ 2015
Water Matters : Kenniskatern voor Waterprofessionals - Dutch edition (2015)oktober. - p. 34 - 37.
evaporatie - waterbeheer - stedelijke gebieden - stedelijke samenleving - waterbehoefte - klimaatverandering - zoet water - evaporation - water management - urban areas - urban society - water requirements - climatic change - fresh water
Hoeveel water verliest een stad door verdamping? Wat betekent dat? En is dat proces van verdamping te beïnvloeden? Onderzoek van Alterra Wageningen UR levert inzichten op die voor de steden steeds belangrijker zullen worden.
Beheerst vocht afvoeren zorg voor energiebesparing : energiebalans toont aan waar de verliezen zitten
Velden, P. van; Raaphorst, M.G.M. ; Zwart, H.F. de - \ 2015
Onder Glas 12 (2015)6/7. - p. 40 - 41.
glastuinbouw - kastechniek - kassen - ontvochtiging - energiebesparing - ventilatie - evaporatie - energiebalans - schermen - modellen - greenhouse horticulture - greenhouse technology - greenhouses - dehumidification - energy saving - ventilation - evaporation - energy balance - blinds - models
Met een model van de energiebalans van een kas lukt het om in één oogopslag de kwetsbare kanten van energieverliezen zichtbaar te maken. Verdamping gebruikt kostbare energie en die vervliegt via de luchtramen als een teler de RV wil verlagen. Dat kan anders, vinden onderzoekers van Wageningen UR Glastuinbouw. Hoe gelijkmatiger het kasklimaat, des te hoger mag de relatieve luchtvochtigheid oplopen.
Assessment of evaporative water loss from Dutch cities
Jacobs, C.M.J. ; Elbers, J.A. ; Brolsma, R. ; Hartogensis, O.K. ; Moors, E.J. ; Rodríguez-CarreteroMárquez, M.T. ; Hove, B. van - \ 2015
Building and Environment 83 (2015). - ISSN 0360-1323 - p. 27 - 38.
klimaatverandering - temperatuur - stedelijke gebieden - evaporatie - waterbudget - rotterdam - veluwe - climatic change - temperature - urban areas - evaporation - water budget - urban heat-island - energy-balance - large-aperture - evapotranspiration - exchange - surface - scintillometers - requirements - environments - manchester
Reliable estimates of evaporative water loss are required to assess the urban water budget in support of division of water resources among various needs, including heat mitigation measures in cities relying on evaporative cooling. We report on urban evaporative water loss from Arnhem and Rotterdam in the Netherlands, using eddy covariance, scintillometer and sapflow observations. Evaporation is assessed at daily to seasonal and annual timescale. For the summer half-year (April–September), observations from Arnhem and Rotterdam are consistent regarding magnitude and variability of evaporation that typically varies between 0.5 and 1.0 mm of evaporation per day. The mean daily evaporative cooling rate was 20–25 Wm-2, 11–14% of the average incoming solar radiation. Evaporation by trees related to sapflow was found to be a small term on the water budget at the city or neighbourhood scale. However, locally the contribution may be significant, given observed maxima of daily sap flows up to 170 l per tree. In Arnhem, evaporation is strongly linked with precipitation, possibly owing to building style. During the summer season, 60% of the precipitation evaporated again. In Rotterdam, the link between evaporation and precipitation is much weaker. An analysis of meteorological observations shows that estimation of urban evaporation from routine weather data using the concept of reference evaporation would be a particularly challenging task. City-scale evaporation may not scale with reference evaporation and the urban fabric results in strong microweather variability. Observations like the ones presented here can be used to evaluate and improve methods for routine urban evaporation estimates.
Unsaturated hydraulic properties of xerophilous mosses: towards implementation of moss covered soils in hydrological models
Voortman, B.R. ; Bartholomeus, R.P. ; Bodegom, P.M. van; Gooren, H.P.A. ; Zee, S.E.A.T.M. van der; Witte, J.P.M. - \ 2014
Hydrological Processes 28 (2014)26. - ISSN 0885-6087 - p. 6251 - 6264.
evaporatie - bryophyta - hydraulisch geleidingsvermogen - korstmossen - mossen - hydrologie - waterbalans - bodemwaterretentie - modelleren - evaporation - hydraulic conductivity - lichens - mosses - hydrology - water balance - soil water retention - modeling - sphagnum moss - water - conductivity - bryophytes - desiccation - ecosystems - tolerance
Evaporation from mosses and lichens can form a major component of the water balance, especially in ecosystems where mosses and lichens often grow abundantly, such as tundra, deserts and bogs. To facilitate moss representation in hydrological models, we parameterized the unsaturated hydraulic properties of mosses and lichens such that the capillary water flow through moss and lichen material during evaporation could be assessed. We derived the Mualem-van Genuchten parameters of the drying retention and the hydraulic conductivity functions of four xerophilous moss species and one lichen species. The shape parameters of the retention functions (2.17¿
A climate robust integrated modelling framework for regional impact assessment of climate change
Janssen, G. ; Bakker, A. ; Ek, R. van; Groot, A.M.E. ; Kroes, J.G. ; Kuiper, M. ; Schipper, P.N.M. ; Walsum, P.E.V. van; Wamelink, W. ; Mol, J. - \ 2013
klimaatverandering - grondwaterstand - gewasgroeimodellen - evaporatie - grondwater - modellen - climatic change - groundwater level - crop growth models - evaporation - groundwater - models
Decision making towards climate proofing the water management of regional catchments can benefit greatly from the availability of a climate robust integrated modelling framework, capable of a consistent assessment of climate change impacts on the various interests present in the catchments. In the Netherlands, much effort has been devoted to developing state-of-the-art regional dynamic groundwater models with a very high spatial resolution (25x25 m2). Still, these models are not completely satisfactory to decision makers because the modelling concepts do not take into account feedbacks between meteorology, vegetation/ crop growth, and hydrology. This introduces uncertainties in forecasting the effects of climate change on groundwater, surface water, agricultural yields, and development of groundwater dependent terrestrial ecosystems. These uncertainties add to the uncertainties about the predictions on climate change itself. In order to create an integrated, climate robust modelling framework, we coupled existing model codes on hydrology, agriculture and nature that are currently in use at the different research institutes in the Netherlands. The modelling framework consists of the model codes MODFLOW (groundwater flow), MetaSWAP (vadose zone), WOFOST (crop growth), SMART2-SUMO2 (soil-vegetation) and NTM3 (nature valuation). MODFLOW, MetaSWAP and WOFOST are coupled online (i.e. exchange information on time step basis). Thus, changes in meteorology and CO2-concentrations affect crop growth and feedbacks between crop growth, vadose zone water movement and groundwater recharge are accounted for. The model chain WOFOST-MetaSWAP-MODFLOW generates hydrological input for the ecological prediction model combination SMART2-SUMO2-NTM3. The modelling framework was used to support the regional water management decision making process in the 267 km2 Baakse Beek-Veengoot catchment in the east of the Netherlands. Computations were performed for regionalized 30-year climate change scenarios developed by KNMI for precipitation and reference evapotranspiration according to Penman-Monteith. Special focus in the project was on the role of uncertainty. How valid is the information that is generated by this modelling framework? What are the most important uncertainties of the input data, how do they affect the results of the model chain and how can the uncertainties of the data, results, and model concepts be quantified and communicated? Besides these technical issues, an important part of the study was devoted to the perception of stakeholders. Stakeholder analysis and additional working sessions yielded insight into how the models, their results and the uncertainties are perceived, how the modelling framework and results connect to the stakeholders’ information demands and what kind of additional information is needed for adequate support on decision making.
Atmospheric effects of irrigation in monsoon climate: the Indian subcontinent
Tuinenburg, O.A. - \ 2013
University. Promotor(en): Pavel Kabat, co-promotor(en): Ronald Hutjes. - S.l. : s.n. - ISBN 9789461734990 - 166
irrigatie - atmosfeer - moesson - evaporatie - waterbudget - india - irrigation - atmosphere - monsoon - evaporation - water budget

During the 20th century, an increasing population increased the demand for food. As a consequence, agricultural activity has expanded and become more intense. A part of this intensification is the use of irrigation systems to water crops. Due to this irrigation, dams and channeling systems, water can be made available for agriculture in places or during seasons with limited precipitation. In monsoon climates, such as India, the majority of the precipitation falls in one season. During the rest of the year, water that is stored in dammed reservoirs can be made available to spread the water availability more evenly over the year. Previous studies with large scale hydrological models have shown that as a consequence of human influences (such as dams and irrigation systems), the river flow decreases during the wet monsoon months, but the evaporation of water into the atmosphere increases during the dry months. However, these large scale hydrological models did not take into account the atmospheric effects of a changed land surface. This PhD research studies these atmospheric effects of large scale irrigation in India. Three perspectives are taken to determined the influence of irrigation: (1) the local effects of a moister land-surface on the triggering of precipitation (i.e. does the change in land surface wetness lead to a different amount of precipitation?), (2) the atmospheric fate of evaporation due to irrigation (i.e. where does the evaporation lead to (down-wind) precipitation?), and (3) the effects of a moister land-surface on the large scale (monsoon) moisture transport patterns (i.e. do the monsoon flows change significantly due to large scale irrigation?) In the first part (the first perspective), several land-atmosphere diagnostics are tested globally. The goal of these diagnostics is to determine the influence of the land surface on precipitation, based on surface and atmospheric conditions. Of these diagnostics, the CTP-HIlow framework (Convective Triggering Potential and Humidity Index of the LOWer atmosphere) of Findell and Eltahir (2003a) performed well globally and over the Indian region. The summertime atmospheric conditions were diagnosed using this framework and the presence of a land-atmosphere coupling hot-spot in the Indian peninsula, proposed by previous studies (Koster et al. (2004)), is confirmed. Secondly, the local perspective is taken in the Indian subcontinent. The CTP- HIlow framework is tested in India, using an atmospheric slab model (a simple, one- dimensional model of the atmosphere) combined with atmospheric soundings (balloon measurements of temperature and moisture of an atmospheric profile of up to 30 km). This model is run twice; once with a wet land surface and once with a dry land surface. The results of these model runs can have two outcomes; the land surface does not have an influence on precipitation or it does have an influence. The CTP-HIlow framework proves to be useful to classify the potential influence of the land surface. When the atmosphere is very wet (low values of HIlow ), precipitation will occur regardless of the land surface, when the atmosphere is very dry (high HIlow values) no precipitation will occur, regardless of the land surface. However, for intermediate HIlow values, the effect of the land surface depends on the stability or the amount of convective energy (CTP) in the atmosphere. The stability of the atmosphere is related to how fast a particle will ascend in the atmosphere, which depends mostly on the temperature profile. For positive, but low convective potentials (0<CTP<200 J/kg), a wet land surface will produce more precipitation than a dry land surface. However, for high amounts of convective potential (CTP>200 J/kg), a dry land surface will produce more precipitation. For India, a small adaptation of the framework improved the performance in predicting the influence of the land surface on precipitation triggering. For India, the effect of the land surface on precipitation is seasonal. During the periods two months before the monsoon onset and after the monsoon retreat, precipitation triggering was found to be sensitive to land surface wetness. During those periods, a wet land surface is expected to increase precipitation. The atmospheric conditions under which a wet land surface is expected to decreases precipitation do not occur frequently in India. During the dry winter season, the atmosphere is too dry for the land surface to have an influence on precipitation. During the monsoon period, the atmosphere is too wet for the land surface to have an influence on precipitation, it will occur regardless of the land surface conditions. In the third part of the study, the moisture recycling perspective was taken and the atmospheric moisture budget of the Ganges basin is studied. A three-dimensional moisture tracing model is used to release moisture parcels from the Ganges basin, similarly to a class of school children releasing helium-filled balloons with their address on it. These parcels were transported along the wind patterns. During the trajectory of the parcel through the atmosphere, some moisture will precipitate out of it and contribute to the precipitation at that location. For each location, many parcels were released for every time step of 6 hours. Similar to the balloons of the school children that are hopefully sent back to them, the fate of the released moisture was accounted. The fraction of the evaporated moisture that subsequently falls as precipitation (recycles) within the Ganges basin shows a strong seasonality. During the winter months, practically all evaporation parcels were transported towards the Indian ocean and were lost for the Ganges basin. During the pre-monsoon months, the recycled fraction increased and was between 30-40%. During the monsoon months, the recycling peaks at up to 60%, after which it drops off again. The importance of recycled evaporation to the total precipitation peaks during the pre-monsoon and post-monsoon periods, when it contributes up to 15% of the precipitation. In the last part of the study, the effects from the local and moisture recycling perspectives are compared to those from the large scale perspective. Four atmospheric models were run with and without irrigation to test the large scale effects of irrigation on the Ganges basin atmospheric water budget and the influence on large scale atmospheric moisture transport. The local effects on precipitation were minimal and not uniform across the models. The Ganges river basin evaporation increased, as well as the amount of evaporation recycled within the river basin. However, the large scale wind patterns showed an uniform change across the models. Due to an increased flow in the direction of north-west India, the precipitation in east-India decreased while it increased in north-west India and Pakistan. Therefore, the Ganges basin precipitation decreased slightly. The conclusion of the work is that from the local perspective and the moisture recycling perspective, irrigation will lead to more precipitation in India. A wetter land surface will trigger some additional precipitation (especially just before and after the monsoon season) and a significant fraction of the evaporation will return to the same river basin as precipitation. However, from the large scale perspective, large scale irrigation will shift the wind patterns due to changes in the land-sea temperature contrast; precipitation will decrease slightly in the Ganges basin and be shifted towards the Indus basin and north-west India. The effects of irrigation on precipitation is small compared to the hydrological response of human influences simulated by the large scale hydrological models. Moreover, the spread in response across these hydrological models is large compared to the simulated effects of irrigation by the atmospheric models. Therefore, it is recommended to improve the large scale hydrological models and reduce their uncertainty before including the feedbacks of land use changes on their precipitation input.

Ontwikkeling emissiemanagementsysteem grondgebonden teelt; modellen
Heinen, Marius ; Assinck, F.B.T. ; Voogt, W. ; Swinkels, G.L.A.M. ; Balendonck, J. - \ 2013
Wageningen : Alterra (Alterra-rapport 2369) - 74
glastuinbouw - chrysanten - chrysanthemum - emissie - simulatiemodellen - lysimeters - stikstof - uitspoelen - evaporatie - greenhouse horticulture - chrysanthemums - emission - simulation models - nitrogen - leaching - evaporation
In het project Glastuinbouw Waterproof - Grondgebonden is een emissiemanagementsysteem ontwikkeld voor de grondgebonden teelt in de glastuinbouw, bestaande uit: 1) een lysimeter en drainmeter, 2) bodemvochtsensoren, 3) modellen, en daarnaast 4) een toetsing in de praktijk. Dit achtergrondrapport gaat nader in op het onderdeel modellen. Op basis van metingen in de kas is de verdamping geschat met een bestaand verdampingsmodel. De berekende verdamping en gemeten irrigatie werden vervolgens doorgegeven aan een bodemmodel waarmee de vochttoestand in de bodem en de drainage onder in de lysimeter werden nagebootst. Deze werden vervolgens vergeleken met de gemeten watergehalten en drainage in de lysimeter. Verschillen in gemeten en gesimuleerde drainage worden toegeschreven aan de onzekerheid in de berekende verdamping. Daarom is de verdamping ook geschat uit de waterbalans over een lange periode. Hieruit zijn correctiefactoren voor het verdampingsmodel afgeleid. Voor de chrysantenteelt bleek dat de verdamping op de bedrijven in dit project met een factor 0.9 moet worden verlaagd.
Ontwikkeling emissiemanagementsysteem grondgebonden teelt; modellen
Heinen, Marius ; Assinck, F.B.T. ; Voogt, W. ; Swinkels, G.L.A.M. ; Balendonck, J. - \ 2012
Bleiswijk : Wageningen UR Glastuinbouw (Rapporten GTB 1192) - 70
vollegrondsteelt - glastuinbouw - lysimeters - emissie - vochtgehalte - evaporatie - modellen - drainage - sensors - outdoor cropping - greenhouse horticulture - emission - moisture content - evaporation - models
In het project ‘Glastuinbouw Waterproof - Grondgebonden’ is een emissiemanagementsysteem ontwikkeld voor de grondgebonden teelt in de glastuinbouw, bestaande uit: 1) lysimeter en drainmeter, 2) bodemvochtsensoren, 3) modellen, en daarnaast 4) een toetsing in de praktijk. Dit achtergrondrapport gaat nader in op het onderdeel modellen. Op basis van metingen in de kas werd de verdamping geschat met behulp van een bestaand verdampingsmodel. De berekende verdamping en gemeten irrigatie werden vervolgens doorgegeven aan een bodemmodel waarmee de vochttoestand in de bodem en de drainage onder in de lysimeter werden gesimuleerd. Deze werden vervolgens vergeleken met de gemeten watergehaltes en drainage in de lysimeter. Verschillen in gemeten en gesimuleerde drainage werden toegeschreven aan de onzekerheid in de berekende verdamping. Daarom is de verdamping ook geschat uit de waterbalans over een lange periode. Hieruit zijn correctiefactoren voor het verdampingsmodel afgeleid
Water use of forests in the Netherlands
Moors, E.J. - \ 2012
Amsterdam : Vrije Universiteit (Alterra scientific contributions 41) - 290
bossen - bostypen - evaporatie - grondwaterspiegel - droogte - watergebruik - peilbeheer - forests - forest types - evaporation - water table - drought - water use - water level management
Forests are complex ecosystems with a large variability in the horizontal as well as in the vertical space. To study the dissimilarities in water use for different forest types, the water and energy balance of five forest stands in the Netherlands were observed during periods varying from two years to more than 15 years. The main tree species of the stands were: Scots pine, poplar, oak, larch and at one site a mixture of pine, birch, beech and oak
Normering van de belastingsituatie droogte : een gestandaardiseerde methode om periodes van droogte en natheid weer te geven
Oostindie, K. ; Wesseling, J.G. ; Ritsema, C.J. - \ 2011
Amersfoort : Stowa (Stowa rapporten ork 2011-w05) - ISBN 9789057735271 - 43 p.
dijken - neerslag - evaporatie - modellen - berekening - veiligheid - testen - droogte - belasting (loads) - dykes - precipitation - evaporation - models - calculation - safety - testing - drought - loads
Deze studie naar het normeren van de situatie ‘langdurige droogte’ is uitgevoerd als onderdeel van de samenstelling van het Addendum op de Leidraad Toets op Veiligheid Regionale Waterkeringen betreffende de boezemkaden.
Simulation of low flows and drought events in WATCH test basins: impact of climate forcing datasets
Huijgevoort, M.H.J. van; Loon, A.F. van; Hanel, M. ; Haddeland, I. ; Horvát, O. ; Koutroulis, A. ; Machlica, A. ; Weedon, G.P. ; Fendeková, M. ; Tsanis, I. ; Lanen, H.A.J. van - \ 2011
2011 : European Commission (Technical report / WATCH no. 44) - 19
geohydrologie - gegevensanalyse - resolutie - aardoppervlak - afvloeiingswater - bodemwater - klimatologie - evaporatie - geohydrology - data analysis - resolution - land surface - runoff water - soil water - climatology - evaporation
The impact of both spatial and temporal resolution on the components of the terrestrial hydrological cycle are investigated using the WATCH forcing dataset (WFD) and the JULES (Joint UK Land Environment Simulator) land surface model. The various spatial resolutions are achieved by degrading the native half degree latitude/longitude resolution WATCH dataset to both one degree and two degrees. The temporal resolutions are created by degrading the native three hourly WATCH forcing dataset to six hourly and using the WATCH interpolator to derive a one hour forcing dataset. There is little difference in the moisture stores of soil water and canopy water in the long term mean from the various resolutions, so the analysis presented is for the changes in evaporation and runoff. The evaporation is further analysed into its various components for the spatial resolution. Results suggest that there is little impact from spatial resolution, but the interpolation method for temporal resolution can have a significant effect on the total mean evaporation/runoff balance.
Soil moisture and root water uptake in climate models. Research Programme Climate Changes Spatial Planning
Dam, J.C. van; Metselaar, K. ; Wipfler, E.L. ; Feddes, R.A. ; Meijgaard, E. van; Hurk, B. van den - \ 2011
WUR + Royal Netherlands Meteorological Institute - ISBN 9789088150128 - 62
bodemwater - bodem-plant relaties - waterbalans - evaporatie - ecohydrologie - klimaatverandering - modellen - soil water - soil plant relationships - water balance - evaporation - ecohydrology - climatic change - models
More accurate simulation of the energy and water balance near the Earth surface is important to improve the performance of regional climate models. We used a detailed ecohydrological model to rank the importance of vegetation and soil factors with respect to evapotranspiration modeling. The results show that type of lower boundary condition, root zone depth, and temporal course of leaf area index have the strongest effect on yearly and monthly evapotranspiration. Soil texture data from the WISE database in combination with HYPRESS pedotransferfunctions can be used to derive more accurate Mualem-van Genuchten type soil moisture retention and hydraulic conductivity functions. We added recent literature data on root densities of agricultural crops to the root data base of Schenk and Jackson. We tested the HTESSEL land routine of the regional climate model RACMO for Western Hungary, which shows systematically too low evapotranspiration and too high air temperatures in many numerical regional climate studies. Satellite remote sensing data, in combination with the SEBAL algorithm, were used to derive evapotranspiration fluxes at a 1x1 km grid for the year 2005. Compared to satellite data, HTESSEL somewhat underestimated evapotranspiration fluxes. This underestimation occurred mainly in regions with irrigation and shallow groundwater, factors which are not included in HTESSEL. Tests with other reduction functions for root water uptake, more realistic soil depth, and a concept for groundwater influence did not yield more accurate spatially distributed evapotranspiration fluxes for Western Hungary.
Lysimeters Castricum : waterbalans lysimeter-1 : ontmaskering van meet- en aanvullingsfouten en het vaststellen van correcties
Hoeven, P.C.T. van der - \ 2011
Wageningen : Alterra (Alterra-rapport 2053-6) - 57 p.
watervoorziening - grondwaterwinning - grondwaterstand - evaporatie - monitoring - hydrologische gegevens - correctiefactoren - lysimeters - waterbalans - duingebieden - kennemerland - water supply - groundwater extraction - groundwater level - evaporation - hydrological data - correction factors - water balance - duneland
De lysimeters van PWN in de duinen van Castricum hebben in de vorige eeuw grote bekendheid gekregen. De wetenschappelijke vraagstelling van de invloed van begroeiing op de aanvulling van het onderliggende grondwater stond in het centrum van de hydrologische belangstelling. Vooral in de periode 1941 - 1972 was niets teveel om zoveel mogelijk gegevens te verzamelen. Piet van der Hoeven heeft in de jaren negentig zich beijverd de archieven voor een ieder beschikbaar te krijgen. Middels deze serie rapporten doet hij verslag van zijn resultaten. Nadat de invoer van de belangrijkste gegevens aan kant was en daar tevens de jacht op fouten eroverheen gegaan was, was duidelijk dat de bestanden daarmee nog geenszins volledig homogeen behoefden te zijn. Het verwijderen van die inhomogeniteiten is het onderwerp van dit rapport.
Beweging der wateren boven, op, in en onder de aarde : berekening Makking-verdamping vanuit temperatuurextremen
Hoeven, P.C.T. van der - \ 2011
Wageningen : Alterra (Alterra-rapport 2053-4) - 23 p.
lysimeters - evaporatie - berekening - hydrologie - grondwaterwinning - duingebieden - kennemerland - evaporation - calculation - hydrology - groundwater extraction - duneland
De lysimeters van PWN in de duinen van Castricum hebben vorige eeuw grote bekendheid gekregen. De wetenschappelijke vraagstelling van de invloed van begroeiing op de aanvulling van het onderliggende grondwater stond in het centrum van de hydrologische belangstelling. Vooral in de periode 1941 - 1972 was niets teveel om zoveel mogelijk gegevens te verzamelen. Piet van der Hoeven heeft in de jaren negentig zich beijverd de archieven voor een ieder beschikbaar te krijgen. Middels deze serie rapporten doet hij verslag van zijn resultaten
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