155 research outputs found

    Departementen onder de loupe

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    Waar houdt het ministerie van Welzijn, Volksgezondheid en Cultuur zich mee bezig? Heeft de aard van die bezigheden wellicht iets te maken met de historische achtergronden van dit ministerie? Welke organisatorische veranderingen hebben de laatste tien jaar plaatsgevonden op het ministerie van Verkeer en Waterstaat? Wat betekenen die veranderingen voor het functioneren van het ministerie? Waarom heeft het ministerie van Defensie verhoudingsgewijs zo weinig externe adviesorganen? En WVC zoveel

    Із зали засідань Президії НАН України

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    На черговому засіданні Президії НАН України 13 червня 2012 року члени Президії НАН України та запрошені заслухали такі питання: Спільне засідання Президії Національної академії наук України та Колегії Державної служби статистики України «Про затвердження проекту програми перепису населення» (доповідачі — заступник голови Держстату України Н.С. Власенко та академік НАН України Е.М. Лібанова); Про наукові підходи до вирішення проблеми збереження та відтворення лісів України (доповідач — член-кореспондент НААН України В.П. Ткач); Про нагородження відзнаками НАН України та Почесними грамотами НАН України і Центрального комітету профспілки працівників НАН України (доповідач — академік НАН України В.Ф. Мачулін); Кадрові та поточні питання

    Assessing flood risk at the global scale: model setup, results, and sensitivity

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    Globally, economic losses from flooding exceeded 19billionin2012,andarerisingrapidly.Hence,thereisanincreasingneedforglobalscalefloodriskassessments,alsowithinthecontextofintegratedglobalassessments.Wehavedevelopedandvalidatedamodelcascadeforproducingglobalfloodriskmaps,basedonnumerousfloodreturnperiods.Validationresultsindicatethatthemodelsimulatesinterannualfluctuationsinfloodimpactswell.Thecascadeinvolves:hydrologicalandhydraulicmodelling;extremevaluestatistics;inundationmodelling;floodimpactmodelling;andestimatingannualexpectedimpacts.Theinitialresultsestimateglobalimpactsforseveralindicators,forexampleannualexpectedexposedpopulation(169million);andannualexpectedexposedGDP(19 billion in 2012, and are rising rapidly. Hence, there is an increasing need for global-scale flood risk assessments, also within the context of integrated global assessments. We have developed and validated a model cascade for producing global flood risk maps, based on numerous flood return-periods. Validation results indicate that the model simulates interannual fluctuations in flood impacts well. The cascade involves: hydrological and hydraulic modelling; extreme value statistics; inundation modelling; flood impact modelling; and estimating annual expected impacts. The initial results estimate global impacts for several indicators, for example annual expected exposed population (169 million); and annual expected exposed GDP (1383 billion). These results are relatively insensitive to the extreme value distribution employed to estimate low frequency flood volumes. However, they are extremely sensitive to the assumed flood protection standard; developing a database of such standards should be a research priority. Also, results are sensitive to the use of two different climate forcing datasets. The impact model can easily accommodate new, user-defined, impact indicators. We envisage several applications, for example: identifying risk hotspots; calculating macro-scale risk for the insurance industry and large companies; and assessing potential benefits (and costs) of adaptation measures

    Linking Ground, Space and Knowledge: The Role of Weather Forecasting in Pastoralists\u27 Decision-Making

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    Changing weather patterns and decreasing land availability continue to challenge the livelihood of the pastoralists in northern Tanzania. The increasing variability of expected rains has complicated livestock management, often jeopardizing household resilience. Drought Early Warning Systems are being set up to contribute to decision-making processes at national and international levels. Nevertheless, due to the large spatial- and temporal resolution of these systems and their high uncertainties, these systems have limited value at a pastoral household level. Therefore, this paper explores what type of weather and climate information is deemed valuable for pastoral households in Longido District, Tanzania. It is based on an ethnographic study, conducted over a period of four months. It explores what weather information would be useful, the necessary scale of desired information, the required lead time of communication and, lastly, the most effective method of communicating forecast information. Following on this data, the study assessed the status of remote sensing and weather forecast modelling, exploring the question, the desired weather information can be forecast with enough skill and at a scale that is relevant to pastoral households in Longido? The ECMWF weather model was used in the assessment, revealing some optimism and scepticism concerning the status of existing information and technologies. Technological recommendations include verification of rainfall data, further research on the rainfall threshold concept, and exploring the model skill of embedded models in Tanzania. At the level of implementation , recommendations include discussing the adverse impacts of actions taken based on the forecasts and forming an implementation advisory group, which includes a comprehensive breadth of stakeholders, such as knowledgeable community members, village leaders, traditional leaders and also professionals from the field of climate sciences, rangeland ecology and anthropology

    KKF-Model Platform Coupling : summary report KKF01b

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    Nederland bereidt zich voor op een sneller stijgende zeespiegel en een veranderend klimaat. Hiervoor is het Deltaprogramma gestart. Dit deltaprogramma voorziet een serie beslissingen die grote gevolgen zullen hebben voor het beheer van het water in Nederland. Om deze beslissingen zorgvuldig te nemen is informatie nodig over hoe het klimaat en de stijgende zeespiegel dit waterbeheer zullen beïnvloeden. De modellen die de gevolgen van klimaatverandering berekenen zullen daarom met dezelfde klimaat forcering en gekoppeld aan elkaar moeten worden gebruikt. In dit onderzoek is gekeken naar het linken van hydrologische en hydrodynamische modellen – en daaraan gekoppelde modellen die de ontwikkelingen in natuur en landgebruik modelleren -- die het gebied van de Alpen tot en met de Noordzee inclusief Nederland beschrijven

    Measuring compound flood potential from river discharge and storm surge extremes at the global scale

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    The interaction between physical drivers from oceanographic, hydrological, and meteorological processes in coastal areas can result in compound flooding. Compound flood events, like Cyclone Idai and Hurricane Harvey, have revealed the devastating consequences of the co-occurrence of coastal and river floods. A number of studies have recently investigated the likelihood of compound flooding at the continental scale based on simulated variables of flood drivers, such as storm surge, precipitation, and river discharges. At the global scale, this has only been performed based on observations, thereby excluding a large extent of the global coastline. The purpose of this study is to fill this gap and identify regions with a high compound flooding potential from river discharge and storm surge extremes in river mouths globally. To do so, we use daily time series of river discharge and storm surge from state-of-the-art global models driven with consistent meteorological forcing from reanalysis datasets. We measure the compound flood potential by analysing both variables with respect to their timing, joint statistical dependence, and joint return period. Our analysis indicates many regions that deviate from statistical independence and could not be identified in previous global studies based on observations alone, such as Madagascar, northern Morocco, Vietnam, and Taiwan. We report possible causal mechanisms for the observed spatial patterns based on existing literature. Finally, we provide preliminary insights on the implications of the bivariate dependence behaviour on the flood hazard characterisation using Madagascar as a case study. Our global and local analyses show that the dependence structure between flood drivers can be complex and can significantly impact the joint probability of discharge and storm surge extremes. These emphasise the need to refine global flood risk assessments and emergency planning to account for these potential interactions

    Advancing catchment hydrology to deal with predictions under change

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    Throughout its historical development, hydrology as an earth science, but especially as a problem-centred engineering discipline has largely relied (quite successfully) on the assumption of stationarity. This includes assuming time invariance of boundary conditions such as climate, system configurations such as land use, topography and morphology, and dynamics such as flow regimes and flood recurrence at different spatio-temporal aggregation scales. The justification for this assumption was often that when compared with the temporal, spatial, or topical extent of the questions posed to hydrology, such conditions could indeed be considered stationary, and therefore the neglect of certain long-term non-stationarities or feedback effects (even if they were known) would not introduce a large error. However, over time two closely related phenomena emerged that have increasingly reduced the general applicability of the stationarity concept: the first is the rapid and extensive global changes in many parts of the hydrological cycle, changing formerly stationary systems to transient ones. The second is that the questions posed to hydrology have become increasingly more complex, requiring the joint consideration of increasingly more (sub-) systems and their interactions across more and longer timescales, which limits the applicability of stationarity assumptions. Therefore, the applicability of hydrological concepts based on stationarity has diminished at the same rate as the complexity of the hydrological problems we are confronted with and the transient nature of the hydrological systems we are dealing with has increased. The aim of this paper is to present and discuss potentially helpful paradigms and theories that should be considered as we seek to better understand complex hydrological systems under change. For the sake of brevity we focus on catchment hydrology. We begin with a discussion of the general nature of explanation in hydrology and briefly review the history of catchment hydrology. We then propose and discuss several perspectives on catchments: as complex dynamical systems, self-organizing systems, co-evolving systems and open dissipative thermodynamic systems. We discuss the benefits of comparative hydrology and of taking an information-theoretic view of catchments, including the flow of information from data to models to predictions. In summary, we suggest that these perspectives deserve closer attention and that their synergistic combination can advance catchment hydrology to address questions of change

    Natural hazard risk assessments at the global scale

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    Since 1990, natural hazards have led to over 1.6 million fatalities globally, and economic losses are estimated at an average of around USD 260–310 billion per year. The scientific and policy communities recognise the need to reduce these risks. As a result, the last decade has seen a rapid development of global models for assessing risk from natural hazards at the global scale. In this paper, we review the scientific literature on natural hazard risk assessments at the global scale, and we specifically examine whether and how they have examined future projections of hazard, exposure, and/or vulnerability. In doing so, we examine similarities and differences between the approaches taken across the different hazards, and we identify potential ways in which different hazard communities can learn from each other. For example, there are a number of global risk studies focusing on hydrological, climatological, and meteorological hazards that have included future projections and disaster risk reduction measures (in the case of floods), whereas fewer exist in the peer-reviewed literature for global studies related to geological hazards. On the other hand, studies of earthquake and tsunami risk are now using stochastic modelling approaches to allow for a fully probabilistic assessment of risk, which could benefit the modelling of risk from other hazards. Finally, we discuss opportunities for learning from methods and approaches being developed and applied to assess natural hazard risks at more continental or regional scales. Through this paper, we hope to encourage further dialogue on knowledge sharing between disciplines and communities working on different hazards and risk and at different spatial scales

    A globally applicable framework for compound flood hazard modeling

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    Coastal river deltas are susceptible to flooding from pluvial, fluvial, and coastal flood drivers. Compound floods, which result from the co-occurrence of two or more of these drivers, typically exacerbate impacts compared to floods from a single driver. While several global flood models have been developed, these do not account for compound flooding. Local-scale compound flood models provide state-of-the-art analyses but are hard to scale to other regions as these typically are based on local datasets. Hence, there is a need for globally applicable compound flood hazard modeling. We develop, validate, and apply a framework for compound flood hazard modeling that accounts for interactions between all drivers. It consists of the high-resolution 2D hydrodynamic Super-Fast INundation of CoastS (SFINCS) model, which is automatically set up from global datasets and coupled with a global hydrodynamic river routing model and a global surge and tide model. To test the framework, we simulate two historical compound flood events, Tropical Cyclone Idai and Tropical Cyclone Eloise in the Sofala province of Mozambique, and compare the simulated flood extents to satellite-derived extents on multiple days for both events. Compared to the global CaMa-Flood model, the globally applicable model generally performs better in terms of the critical success index (−0.01–0.09) and hit rate (0.11–0.22) but worse in terms of the false-alarm ratio (0.04–0.14). Furthermore, the simulated flood depth maps are more realistic due to better floodplain connectivity and provide a more comprehensive picture as direct coastal flooding and pluvial flooding are simulated. Using the new framework, we determine the dominant flood drivers and transition zones between flood drivers. These vary significantly between both events because of differences in the magnitude of and time lag between the flood drivers. We argue that a wide range of plausible events should be investigated to obtain a robust understanding of compound flood interactions, which is important to understand for flood adaptation, preparedness, and response. As the model setup and coupling is automated, reproducible, and globally applicable, the presented framework is a promising step forward towards large-scale compound flood hazard modeling.</p
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