4075 resultaten

  • The effect of grid resolution and weather forcing on hydrodynamic modelling of South East Asian waters

    Auteurs: Ooi, S.K.; Sisomphon, P.; Gerritsen, H.; Twigt, D.J. (2009)

    The flows in Malacca Strait and Singapore waters are the result of complex tidal interactions of the Indian and Pacific Oceans, monsoon effects and furtheratmospheric forcing. For modelling the tidal flow, the authors use the SingaporeRegional Model (SRM).

  • Discharge simulations performed with a hydrological model using bias corrected regional climate model input

    Auteurs: Pelt, S.C. van; Kabat, P.; Maat, H.W. ter; Hurk, B.J.J.M. van den; Weerts, A.H. (2009)
    Gepubliceerd in: Hydrology and earth system sciences, volume 13 (2009) nummer 12, pagina 2387-2397

    Studies have demonstrated that precipitation on Northern Hemisphere mid-latitudes has increased in the last decades and that it is likely that this trend will continue. This will have an influence on discharge of the river Meuse. The use of bias correction methods is important when the effect of precipitation change on river discharge is studied. The objective of this paper is to investigate the effect of using two different bias correction methods on output from a Regional Climate Model (RCM) simulation. In this study a Regional Atmospheric Climate Model (RACMO2) run is used, forced by ECHAM5/MPIOM under the condition of the SRES-A1B emission scenario, with a 25 km horizontal resolution. The RACMO2 runs contain a systematic precipitation bias on which two bias correction methods are applied. The first method corrects for the wet day fraction and wet day average (WD bias correction) and the second method corrects for the mean and coefficient of variance (MV bias correction). The WDbias correction initially corrects well for the average, but it appears that too many successive precipitation days were removed with this correction. The second method performed less well on average bias correction, but the temporal precipitation pattern was better. Subsequently, the discharge was calculated by using RACMO2 output as forcing to the HBV-96 hydrological model. A large difference was found between the simulated discharge of the uncorrected RACMO2 run, the WD bias corrected run and the MV bias corrected run. These results show the importance of an appropriate bias correction.

  • Stochastic modelling of the coastline position along the Holland Coast (The Netherlands)

    Auteurs: Brière, C.D.E.; Boogaard, H.F.P. van den (2009)

  • Compartmentalisation : flood consequence reduction by splitting up large polder areas

    Auteurs: Klijn, F.; Asselman, N.E.M.; Most, H. van der (2010)
    Gepubliceerd in: Journal of flood risk management, volume 3 (2010) nummer 1, pagina 3-17

    River and coastal floodplains are often protected by vast systems of connectedembankments. In the Netherlands, about 55% of the country is protected in this way, by some 3600km of primary defences. The protection level is probably the highest in the world, and annual mean flood risks are low. Nevertheless, the consequences of a major flood event might be unacceptable. This is a reason to consider whether and how the consequences of floods could be reduced in a costeffective manner. Splitting up large polder areas into smaller portions, the so-called compartmentalisation, would reduce the area subject to flooding, and thus the economic damage, the number of people exposed and the fatality risk. We carried out a policy analysis for the national authorities in order to establish whether, where and under which conditions a further compartmentalisation of the country would be desirable. This paper gives some results, discusses our experiences in four case studies and finally focuses on the fundamental questions of assessment and the trade-off between better flood protection and the benefit/cost ratio of reducing consequences.

  • Electrokinetic study of kaolinite suspensions

    Auteurs: Chassagne, C.; Mietta, F.; Winterwerp, J.C. (2009)

    Kaolinite is a mineral that has a wide range of applications in industry, as it is used in paints and ink and is a major component of ceramics. It is also a mineral widely found in nature and as suchcontributes to the properties of soils. The structure and chemical properties of kaolinite therefore have been extensively studied (see for example [1-7]).

  • Real-time geospatial data handling and forecasting : examples from Delft-FEWS forecasting platform/system

    Auteurs: Weerts, A.H.; Schellekens, J.; Sperna Weiland, F.C. (2010)
    Gepubliceerd in: IEEE journal of selected topics in applied earth observations and remote sensing, volume 3 (2010) nummer 3, pagina 386-394

  • Enhancing generic ecological model for short-term prediction Southern North Sea algal dynamics with remote sensing images

    Auteurs: Li, H.; Arias Hidalgo, M.E.; Blauw, A.N.; Los, F.J.; Mynett, A.E. (2010)
    Gepubliceerd in: Ecological modelling : international journal on ecological modelling and engineering and systems ecology, volume 221 (2010), pagina 2435-2446

    In this paper the BLOOM/GEM model for prediction of Harmful algal blooms is extended with TSM results from remote sensing.

  • Nonylphenol mass transfer from field-aged sediments and subsequent biodegradation in reactors mimicking different river conditions

    Auteurs: Weert, J.P.A. de; Streminska, M.; Langenhoff, A.A.M.; Rijnaarts, H.H.M. (2010)
    Gepubliceerd in: Journal of soils and sediments, volume 10 (2010), pagina p. 77-88

  • Degassing of 3H/3He, CFCs and SF6 by denitrification : measurements and two-phase transport simulations

    Auteurs: Visser, A.; Schaap, J.D.; Broers, H.P.; Bierkens, M.F.P. (2009)
    Gepubliceerd in: Journal of contaminant hydrology, volume 103 (2009) nummer 3-4, pagina 206-218

    The production of N2 gas by denitrification may lead to the appearance of a gas phase below the water table prohibiting the conservative transport of tracer gases required for groundwater dating. We used a two-phase flow and transport model (STOMP) to study the reliability of 3H/3He, CFCs and SF6 as groundwater age tracers under agricultural landwhere denitrification causes degassing. Wewere able to reproduce theamount of degassing (R2=69%), aswell as the 3H(R2=79%)and3He⁎ (R2=76%) concentrations observed in a 3H/3He data set using simple 2Dmodels.We found that the TDG correction of the 3H/3He age overestimated the control 3He/3He age by 2.1 years, due to the accumulation of 3He⁎ in the gas phase. The total uncertainty of degassed 3H/3Heages of 6 years (±2 σ) is due to the correction of degassed 3He⁎ using the TDGmethod, but also due to the travel time in the unsaturated zone and the diffusion of bomb peak 3He⁎. CFCs appear to be subject to significant degradation in anoxic groundwater and SF6 is highly susceptible to degassing. We conclude that 3H/3He is the most reliable method to date degassed groundwater and that twophase flow models such as STOMP are useful tools to assist in the interpretation of degassed groundwater age tracer data.

  • On the behaviour of open filters under wave loading

    Auteurs: Wolters, G.; Rudolph, D.; Hofland, B.; Verheij, H.J. (2010)

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