1,721,002 research outputs found
Dependence between high sea-level and high river discharge increases flood hazard in global deltas and estuaries
No full textWhen river and coastal floods coincide, their impacts are often worse than when they occur in isolation; such floods are examples of ‘compound events’. To better understand the impacts of these compound events, we require an improved understanding of the dependence between coastal and river flooding on a global scale. Therefore, in this letter, we: provide the first assessment and mapping of the dependence between observed high sea-levels and high river discharge for deltas and estuaries around the globe; and demonstrate how this dependence may influence the joint probability of floods exceeding both the design discharge and design sea-level. The research was carried out by analysing the statistical dependence between observed sea-levels (and skew surge) from the GESLA-2 dataset, and river discharge using gauged data from the Global Runoff Data Centre, for 187 combinations of stations across the globe. Dependence was assessed using Kendall’s rank correlation coefficient () and copula models. We find significant dependence for skew surge conditional on annual maximum discharge at 22% of the stations studied, and for discharge conditional on annual maximum skew surge at 36% of the stations studied. Allowing a time-lag between the two variables up to 5 days, we find significant dependence for skew surge conditional on annual maximum discharge at 56% of stations, and for discharge conditional on annual maximum skew surge at 54% of stations. Using copula models, we show that the joint exceedance probability of events in which both the design discharge and design sea-level are exceeded can be several magnitudes higher when the dependence is considered, compared to when independence is assumed. We discuss several implications, showing that flood risk assessments in these regions should correctly account for these joint exceedance probabilities
Paired time series of daily discharge and storm surge
No full textThis dataset presents daily time series of discharge and maximum storm surge at river mouths globally from 1980 - 2014.
Daily river discharge is the product of routing the mean daily runoff of the JULES model from the eartH2Observe WRR2 reanalysis data at 0.5° resolution (Best et al., 2011; Clark et al., 2011; Schellekens et al., 2017) with CaMa-Flood at a 0.25° resolution (Yamazaki et al., 2011). The maximum daily storm surge is obtained from the Global Tide and Surge Model (GTSM) (Muis et al., 2016; Verlaan et al., 2015). Each discharge location at the river mouth of coastal catchments larger than 1,000 km2 is paired with the nearest (≤ 75 km) GTSM output location (Eilander et al., 2019).
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Long-term sea-level rise necessitates a commitment to adaptation: a first order assessment
Get PDFWithout adaptation, sea-level rise (SLR) will put more people at risk of flooding. This requires a timely and adequate commitment to adaptation. In this paper, we show how adaptation needs to unfold over time to manage climate-induced SLR. We use a novel scenario-neutral approach, applied globally and subsequently combined with SLR and population scenarios, to assess when, where, and how fast to adapt up to 2150. As rates of SLR accelerate, adaptation needs to occur at an increasing pace or at a larger scale. While it is certain that adaptation will be necessary, it is uncertain when and how fast. After only ~0.15m SLR relative to 2020, 1 million people need to adapt to permanent submergence and the amount of people at risk of a 100-year flood increases with 21% to 83 million people. This would occur in the next 30 (20-45) years for RCP4.5 and within 25 (18-36) years under RCP8.5, assuming no change in protection or population. The uncertainty in timing increases with higher SLR, albeit for some impacts it can still a matter of time. Population at risk of a 100-year flood doubles after 0.75m SLR which could occur by ~2080 (2068-2088), 2100 (2085-2130), or 2150 (2115-beyond 2150) under a high-end, RCP8.5, or RCP4.5 scenario respectively. The rate, at which the risk increases, differs strongly per country. In some countries an additional 1-5 million people of the present population will be at risk of a 100-year flood within the next two decades, while others have more time to adapt but will see rapid growth of risk past 2100. Combining SLR impacts with projected population change further increases the number of people at risk of a 100-year flood by ~13% between 2040-2060 (under both RCP8.5-SSP5 or RCP4.5-SSP2). This can be managed through protecting, floodproofing or limiting developments in high-risk areas. A commitment to adaptation is inevitable to maintain risk at present levels. With increasing warnings of the potential for accelerated SLR due to rapid ice sheet melt, adaptation may need to happen faster and sooner than previously anticipated which can have consequences for how to adapt. Failure to acknowledge the potential and long-term (including beyond 2100) adaptation commitment in development and adaptation planning may lead to a commitment gap and subsequently expensive retrofitting of infrastructure, creation of stranded assets, and less time to adapt at greater cost. In contrast, considering the long-term adaptation commitment can support timely adaptation and alignment with other societal goals
Paired time series of daily discharge and storm surge
No full textThis dataset presents daily time series of discharge and maximum storm surge at river mouths globally from 1980 - 2014.
Daily river discharge is the product of routing the mean daily runoff of the JULES model from the eartH2Observe WRR2 reanalysis data at 0.5° resolution (Best et al., 2011; Clark et al., 2011; Schellekens et al., 2017) with CaMa-Flood at a 0.25° resolution (Yamazaki et al., 2011). The maximum daily storm surge is obtained from the Global Tide and Surge Model (GTSM) (Muis et al., 2016; Verlaan et al., 2015). Each discharge location at the river mouth of coastal catchments larger than 1,000 km2 is paired with the nearest (≤ 75 km) GTSM output location (Eilander et al., 2019).
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Review article: a comprehensive review of compound flooding literature with a focus on coastal and estuarine regions
No full textCompound flooding, where the combination or successive occurrence of two or more flood drivers leads to a greater impact, can exacerbate the adverse consequences of flooding, particularly in coastal--estuarine regions. This paper reviews the practices and trends in coastal-estuarine compound flood research and synthesizes regional to global findings. A systematic review is employed to construct a literature database of 279 studies relevant to compound flooding in a coastal-estuarine context. This review explores the types of compound flood events and their mechanistic processes, and it synthesizes terminology throughout the literature. Considered in the review are six flood drivers (fluvial, pluvial, coastal, groundwater, damming/dam failure, and tsunami) and five precursor events and environmental conditions (soil moisture, snow, temp/heat, fire, and drought). Furthermore, this review summarizes research methodology and study application trends, as well as considers the influences of climate change and urban environments. Finally,this review highlights knowledge gaps in compound flood research and discusses the implications on future practices. Our five recommendations for compound flood research are (1) adopt consistent terminology and approaches, (2) expand the geographic coverage of research, (3) pursue more inter-comparison projects, (4) develop modelling frameworks that better couple dynamic Earth systems, and (5) design urban and coastal infrastructure with compounding in mind.<br/
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A comprehensive review of coastal compound flooding literature
No full textCompound flooding, where the combination or successive occurrence of two or more flood drivers leads to an extreme impact, can greatly exacerbate the adverse consequences associated with flooding in coastal regions. This paper reviews the practices and trends in coastal compound flood research methodologies and applications, as well as synthesizes key findings at regional and global scales. Systematic review is employed to construct a literature database of 271 studies relevant to compound flood hazards in a coastal context. This review explores the types of compound flood events, their mechanistic processes, and synthesizes the definitions and terms exhibited throughout the literature. Considered in the review are six flood drivers (fluvial, pluvial, coastal, groundwater, damming/dam failure, and tsunami) and five precursor events and environmental conditions (soil moisture, snow, temp/heat, fire, and drought). Furthermore, this review summarizes the trends in research methodology, examines the wide range of study applications, and considers the influences of climate change and urban environments. Finally, this review highlights the knowledge gaps in compound flood research and discusses the implications of review findings on future practices. Our five recommendations for future compound flood research are to: 1) adopt consistent definitions, terminology, and approaches; 2) expand the geographic coverage of research; 3) pursue more inter-comparison projects; 4) develop modelling frameworks that better couple dynamic earth systems; and 5) design urban and coastal infrastructure with compound flooding in mind. We hope this review will help to enhance understanding of compound flooding, guide areas for future research focus, and close knowledge gaps
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