Exploring pathways for sustainable water management in river deltas in a changing environment   总被引：2，自引：1，他引：1  

Marjolijn Haasnoot  Hans Middelkoop  Astrid Offermans  Eelco van Beek  Willem P. A. van Deursen 《Climatic change》2012,115(3-4):795-819

Exploring adaptation pathways into an uncertain future can support decisionmaking in achieving sustainable water management in a changing environment. Our objective is to develop and test a method to identify such pathways by including dynamics from natural variability and the interaction between the water system and society. Present planning studies on long-term water management often use a few plausible futures for one or two projection years, ignoring the dynamic aspect of adaptation through the interaction between the water system and society. Our approach is to explore pathways using multiple realisations of transient scenarios with an Integrated Assessment Meta Model (IAMM). This paper presents the first application of the method using a hypothetical case study. The case study shows how to explore and evaluate adaptation pathways. With the pathways it is possible to identify opportunities, threats, timing and sequence of policy options, which can be used by policymakers to develop water management roadmaps into the future. By including the dynamics between the water system and society, the influence of uncertainties in both systems becomes clearer. The results show, among others, that climate variability rather than climate change appears to be important for taking decisions in water management.  相似文献   

Characterising meridional overturning bistability using a minimal set of state variables   总被引：1，自引：1，他引：0  

Willem P. Sijp 《Climate Dynamics》2012,39(9-10):2127-2142

A close approximation of key state variables and salt fluxes for both the North Atlantic Deep Water (NADW) “on” and “off” states in a General Circulation Model (GCM) is constructed, yielding a natural stability condition. Here, stability is linked to the effect of feedbacks on infinitesimal salinity anomalies on the average Atlantic salinity. The stability condition simply states that the total advective salt feedback must be negative in each steady state, ensuring stability by damping the growth of infinitesimal salinity perturbations. However, a decomposition of the salt feedback into three components shows that only the interaction between the mean salinity and infinitesimal perturbations of the meridional flow have the potential to render a state unstable, holding the key to state transitions. In contrast, the interaction between the mean meridional flow and infinitesimal salinity perturbations yields a negative (stabilising) component feedback. Similarly, the gyre salt flux also stabilises the overturning states. Furthermore, the nodes limiting the “on” and “off” state regimes in the GCM can be accurately computed based on linear fits of basic state variables and the gyre salt flux. It is shown that the NADW “on” state closest to collapse must be contained within a neighbourhood of fresh water exporting states. Finally, the role of temperature in the bistability structure is elucidated.  相似文献   

Escherichia coli strains harvested from springs in Kampala,Uganda: cell characterization and transport in saturated porous media          下载免费PDF全文

George Lutterodt  Jan Willem A. Foppen  Stefan Uhlenbrook 《水文研究》2014,28(4):1973-1988

We hypothesized that the transport of Escherichia coli strains harvested from springs could be characterized by a similar set of cell characteristics and transport parameters. The hypothesis was tested by sampling springs throughout the Lubigi catchment in Kampala, Uganda. Chemo‐physical parameters in addition to total coliform concentrations were determined. Furthermore, E. coli strains were harvested, and cell properties determined. Column experiments in saturated quartz columns of 7 cm height were conducted to determine transport parameters of selected E. coli strains. Using a two‐site non‐equilibrium sorption model, transport was modelled by fitting breakthrough data in HYDRUS 1D. Results indicated faecal contamination of the springs with high concentrations of total coliforms, chloride and nitrate. Furthermore, the maximum relative E. coli concentrations (C/C₀)_max in the column experiments were high. Compared with our previous work on E. coli strains, collected from a pasture and from zoo animals, attachment was low. Modelling revealed that both equilibrium and kinetic sorption were not important under conditions employed in the experiments. These observations are explained by the way in which the strains were harvested: from termination points of flow lines (springs). Such strains may possess characteristics that might have influenced their transport in the subsurface leading to their low attachment efficiency and possibly contributing to the lack of influence of equilibrium and kinetic sorption characteristics. There was no significant correlation between cell properties and transport parameters. Furthermore, 58% of the tested strains were of the O21:H7 serotype, and all definable serotypes identified were associated with diseases. We speculate that this serotype may possess characteristics that allow preferential transport through the aquifers of the area. We demonstrated that bacteria harvested from termination points of flow lines compared with those obtained from pollution sources, which have not undergone transport yet, present a good option for the assessment of bacteria transport characteristics in aquifers. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Quaternary Environmental Change in the Tropics,edited by Sarah E. Metcalfe and David J. Nash. Wiley‐Blackwell,Chichester, 2012. No of pages: xiv + 421. Price: UK£62.50 (hardback). ISBN: 978‐1‐118‐34325‐8.     

Willem Rnema 《Geological Journal》2016,51(3):501-501

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Sun–Earth L_{1} and L_{2} to Moon transfers exploiting natural dynamics     

Willem Johan van der Weg  Massimiliano Vasile 《Celestial Mechanics and Dynamical Astronomy》2014,120(3):287-308

This paper examines the design of transfers from the Sun–Earth libration orbits, at the \(L_{1}\) and \(L_{2}\) points, towards the Moon using natural dynamics in order to assess the feasibility of future disposal or lifetime extension operations. With an eye to the probably small quantity of propellant left when its operational life has ended, the spacecraft leaves the libration point orbit on an unstable invariant manifold to bring itself closer to the Earth and Moon. The total trajectory is modeled in the coupled circular restricted three-body problem, and some preliminary study of the use of solar radiation pressure is also provided. The concept of survivability and event maps is introduced to obtain suitable conditions that can be targeted such that the spacecraft impacts, or is weakly captured by, the Moon. Weak capture at the Moon is studied by method of these maps. Some results for planar Lyapunov orbits at \(L_{1}\) and \(L_{2}\) are given, as well as some results for the operational orbit of SOHO.  相似文献   

Report on the Tenth UN/ESA Workshop on Basic Space Science: Exploring the Universe – Sky Surveys, Space Exploration, and Space Technologies     

Hans J. Haubold  Willem Wamsteker 《Astrophysics and Space Science》2002,282(1):341-357

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Study of groundwater contamination by radioactive brine: the Lake Karachai case     

V. Rumynin  L. Sindalovskiy  P. Konosavsky  A. Boronina  C. Gallo  Willem J. Zaadnoordijk 《Environmental Geology》2002,42(2-3):187-198

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Fossils explained 47     

Willem Renema  & Stephen K. Donovan 《Geology Today》2004,20(6):233-236

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Fundamental Problems in Astrophysics     

Ana I. Gómez de Castro  Willem Wamsteker  Martin Barstow  Noah Brosch  Norbert Kappelmann  Wollfram Kollatchny  Domitilla de Martino  Isabella Pagano  Alain Lecavelier des Étangs  David Ehenreich  Dieter Reimers  Rosa González Delgado  Francisco Najarro  Jeff Linsky 《Astrophysics and Space Science》2006,303(1-4):133-145

Progress of modern astrophysics requires the access to the electromagnetic spectrum in the broadest energy range. The Ultraviolet is a fundamental energy domain since it is one of the most powerful tool to study plasmas at temperatures in the 3,000–300,000 K range as well as electronic transitions of the most abundant molecules in the Universe. Moreover, the UV radiation field is a powerful astrochemical and photoionizing agent.The objective of this review is to describe the crucial issues that require access to the UV range. A summary has been added to the end with a more classic view of UV needs by astronomical object type; this approach is followed at length in the rest of the contributions of this issue.  相似文献   

Instructions for Authors     

John?DysonEmail author  Willem?Wamsteker 《Astrophysics and Space Science》2005,299(4):419-425

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