scholarly journals A NEW METHOD OF APPROACHING EXTREME STORM EVENTS FOR DESIGN LEVEL OR RISK ANALYSIS

2012 ◽  
Vol 1 (33) ◽  
pp. 2 ◽  
Author(s):  
Gabriele Goennert ◽  
Birgit Gerkensmeier
Keyword(s):  
Risk Analysis ◽  
Storm Surge ◽  
Research Work ◽  
Storm Surges ◽  
New Method ◽  
Storm Events ◽  
Extreme Storm ◽  
Joint Research Project ◽  
Non Linear ◽  
Linear Interactions

The North Sea coast is seriously threatened by storm surges. Climate change and its consequences, such as a rising sea level, will have serious effects on the safety of people and economic assets in coastal areas. Within the joint research project XtremRisK (bmbf-funded) the Agency of roads bridges and Waters of the Free and Hanseatic City of Hamburg developed a new method to calculate extreme storm surge events. The purpose of the research work, to calculated physically feasible extreme events is given consideration by detailed analyses of the single storm-surge components (tide, external surge from the Atlantic and wind surge) and their non-linear interactions by combining deterministic-empirical, statistical and numerical methods. The non-linear interactions can be comprised by hydrodynamic equations such as equation of momentum, continuity equation and volume balance. The claim to develop a comprehensive and physically feasible method is satisfied by the diversity of methodical approaches for analyzing the storm surge components and their interaction processes. Therefore a 2-method concept is developed on the basis of empirical and numerical approaches. The resultant new method is a new way of calculating extreme storm surges and can be used within new design concepts to calculate design level heights or could be a part of risk analysis

scholarly journals FAILURE PROBABILITY OF FLOOD DEFENCE STRUCTURES/ SYSTEMS IN RISK ANALYSIS FOR EXTREME STORM SURGES

2011 ◽  
Vol 1 (32) ◽  
pp. 13 ◽  
Author(s):  
Marie Naulin ◽  
Andreas Kortenhaus ◽  
Hocine Oumeraci
Keyword(s):  
Risk Analysis ◽  
Failure Probability ◽  
Storm Surges ◽  
Joint Research ◽  
Extreme Storm ◽  
Integrated Risk ◽  
Joint Research Project ◽  
Integrated Risk Analysis ◽  
Flood Defence ◽  
Failure Probabilities

Extreme storm surges can cause failures of flood defences resulting in severe flooding of the hinterland and catastrophic damages. In order to quantify the risk of flooding an integrated risk analysis is being performed wherein one task is the determination of failure probabilities of flood defences. In this paper the failure probability calculations of flood defence structures and systems under the loading of extreme storm surges are reported. Moreover, the analysis of the breach and breach development is briefly introduced. Preliminary results of the failure probabilities and the breach modelling are presented using the example of the estuarine urban area of Hamburg, Germany. These results are put in context of an integrated risk analysis approach for extreme storm surges which is applied within an ongoing German joint research project.

scholarly journals INTEGRATED FLOOD RISK ANALYSIS FOR EXTREME STORM SURGES (XTREMRISK)

2011 ◽  
Vol 1 (32) ◽  
pp. 9 ◽  
Author(s):  
Andreas Burzel ◽  
Dilani R. Dassanayake ◽  
Marie Naulin ◽  
Andreas Kortenhaus ◽  
Hocine Oumeraci ◽  
...  
Keyword(s):  
Risk Analysis ◽  
Flood Risk ◽  
Risk Mitigation ◽  
Storm Surges ◽  
Mitigation Measures ◽  
Joint Research ◽  
Extreme Storm ◽  
Joint Research Project ◽  
Flood Risk Analysis ◽  
First Results

Extreme storm surges have frequently led to major damages also along the German coastline. The joint research project 'XtremRisK' was initiated to improve the understanding of risk-related issues due to extreme storm surges and to quantify the flood risk for two pilot sites at the open coast and in an estuarine area under present and future climate scenarios. In this context, an integrated flood risk analysis is performed based on the source-pathway-receptor concept under consideration of possible tangible and intangible losses. This paper describes the structure of the project, the methodology of the subprojects, and first results. Moreover, integration approaches are discussed. The results of 'XtremRisK' will be used to propose flood risk mitigation measures for the prospective end-users.

Integrated flood risk analysis for extreme storm surges at open coasts and in estuaries

2012 ◽  
Author(s):  
H Oumeraci ◽  
A Kortenhaus ◽  
A Burzel ◽  
M Naulin ◽  
D Dassanayake ◽  
...  
Keyword(s):  
Risk Analysis ◽  
Flood Risk ◽  
Storm Surges ◽  
Extreme Storm ◽  
Flood Risk Analysis

scholarly journals Statistical Prediction of Extreme Storm Surges Based on a Fully Supervised Weather-Type Downscaling Model

2020 ◽  
Vol 8 (12) ◽  
pp. 1028
Author(s):  
Wagner Costa ◽  
Déborah Idier ◽  
Jérémy Rohmer ◽  
Melisa Menendez ◽  
Paula Camus
Keyword(s):  
Storm Surge ◽  
Storm Surges ◽  
Absolute Error ◽  
Weather Type ◽  
Statistical Prediction ◽  
Daily Maximum ◽  
Maximum Absolute Error ◽  
Extreme Storm ◽  
Gauge Station ◽  
Data Driven Approach

Increasing our capacity to predict extreme storm surges is one of the key issues in terms of coastal flood risk prevention and adaptation. Dynamically forecasting storm surges is computationally expensive. Here, we focus on an alternative data-driven approach and set up a weather-type statistical downscaling for daily maximum storm surge (SS) prediction, using atmospheric hindcasts (CFSR and CFSv2) and 15 years of tidal gauge station measurements. We focus on predicting the storm surge at La Rochelle–La Pallice tidal gauge station. First, based on a sensitivity analysis to the various parameters of the weather-type approach, we find that the model configuration providing the best performance in SS prediction relies on a fully supervised classification using minimum daily sea level pressure (SLP) and maximum SLP gradient, with 1° resolution in the northeast Atlantic domain as the predictor. Second, we compare the resulting optimal model with the inverse barometer approach and other statistical models (multi-linear regression; semi-supervised and unsupervised weather-types based approaches). The optimal configuration provides more accurate predictions for extreme storm surges, but also the capacity to identify unusual atmospheric storm patterns that can lead to extreme storm surges, as the Xynthia storm for instance (a decrease in the maximum absolute error of 50%).

scholarly journals SPATIAL MODELLING OF TANGIBLE AND INTANGIBLE LOSSES IN AN INTEGRATED RISK ANALYSIS

2012 ◽  
Vol 1 (33) ◽  
pp. 65
Author(s):  
Andreas Burzel ◽  
Dilani R. Dassanayake ◽  
Hocine Oumeraci
Keyword(s):  
Risk Analysis ◽  
Flood Risk ◽  
Storm Surges ◽  
Spatial Modelling ◽  
Economic Losses ◽  
Climate Conditions ◽  
Extreme Storm ◽  
Flood Risk Analysis ◽  
Integrated Risk Analysis ◽  
The Impact

The expected climate change and the associated possible increase of the frequency and magnitude of extreme storm surges may lead to larger storm surge hazards than have been observed in the past. Therefore, the German XtremRisK project aims to improve the understanding of the impact of extreme storm surges under current and future climate conditions by conducting an integrated flood risk analysis for two selected pilot sites in Germany which may be representative for an open coast (Sylt Island) and a megacity in an estuarine area (Hamburg). The research has also been focused on developing and improving the knowledge, methods and models for the assessment of intangible losses (social and environmental), their spatial modelling as well as their integration with direct and indirect economic losses. After a brief introduction into the integrated flood risk analysis being implemented, the paper describes the methodologies and discusses the results with a focus on the modelling of tangible and intangible losses in the pilot site Hamburg-Wilhelmsburg.

scholarly journals Estimation of the non-exceedance probability of extreme storm surges in South Korea using tidal-gauge data

2021 ◽  
Vol 21 (8) ◽  
pp. 2611-2631
Author(s):  
Sang-Guk Yum ◽  
Hsi-Hsien Wei ◽  
Sung-Hwan Jang
Keyword(s):  
South Korea ◽  
Water Level ◽  
Storm Surge ◽  
Storm Surges ◽  
Exceedance Probability ◽  
Probability Models ◽  
Distribution Models ◽  
Sea Levels ◽  
Extreme Storm ◽  
Gauge Data

Abstract. Global warming, one of the most serious aspects of climate change, can be expected to cause rising sea levels. These have in turn been linked to unprecedentedly large typhoons that can cause flooding of low-lying land, coastal invasion, seawater flows into rivers and groundwater, rising river levels, and aberrant tides. To prevent typhoon-related loss of life and property damage, it is crucial to accurately estimate storm-surge risk. This study therefore develops a statistical model for estimating such surges' probability based on surge data pertaining to Typhoon Maemi, which struck South Korea in 2003. Specifically, estimation of non-exceedance probability models of the typhoon-related storm surge was achieved via clustered separated peaks-over-threshold simulation, while various distribution models were fitted to the empirical data for investigating the risk of storm surges reaching particular heights. To explore the non-exceedance probability of extreme storm surges caused by typhoons, a threshold algorithm with clustering methodology was applied. To enhance the accuracy of such non-exceedance probability, the surge data were separated into three different components: predicted water level, observed water level, and surge. Sea-level data from when Typhoon Maemi struck were collected from a tidal-gauge station in the city of Busan, which is vulnerable to typhoon-related disasters due to its geographical characteristics. Fréchet, gamma, log-normal, generalized Pareto, and Weibull distributions were fitted to the empirical surge data, and the researchers compared each one's performance at explaining the non-exceedance probability. This established that Weibull distribution was better than any of the other distributions for modelling Typhoon Maemi's peak total water level. Although this research was limited to one city on the Korean Peninsula and one extreme weather event, its approach could be used to reliably estimate non-exceedance probabilities in other regions where tidal-gauge data are available. In practical terms, the findings of this study and future ones adopting its methodology will provide a useful reference for designers of coastal infrastructure.

Re-assessing extreme sea level events through interplay of tides and storm surges

2020 ◽  
Author(s):  
Stephen Outten ◽  
Tobias Wolf ◽  
Fabio Mangini ◽  
Linling Chen ◽  
Jan Even Nilsen
Keyword(s):  
Sea Level ◽  
Storm Surge ◽  
Critical Infrastructure ◽  
Tide Gauge ◽  
Storm Surges ◽  
Return Level ◽  
National Standard ◽  
Moderate Intensity ◽  
Extreme Storm ◽  
Warming World

<p>Flooding events pose an ever increasing threat in a warming world. Safety standards for buildings and infrastructure are often based on past observations of local sea level, as measured by tide gauges and remote sensing systems. However, sea level at a given location is not an isolated property and is determined by a combination of factors. For extreme sea level events, there are two factors that of particular importance: the astronomical tide, and storm surges. In this work, we analysed measurements from 21 stations in the Norwegian tide gauge network, disentangling the factors contributing to the previously observed extreme events.</p><p>By separating the observed sea level into a tidal component and a storm surge component, we found that in many cases the observed extreme sea level events were caused by an extreme storm surge coinciding with only a moderate tide, or an extreme tide coinciding with only a moderate storm surge. This raises the possibility of a ‘super-flooding’ event, where an extreme storm surge may occur with an extreme tide. Even in the short records examined in this study (less than 40 years), the combination of the highest observed tide with the highest observed storm surge would greatly exceed in the 1000-year return level event at many locations. This is often used as a national standard for critical infrastructure.  </p><p>We further complement the work by analysing the storm tracks close to Norway. By relating the storm surges with the individual storms giving rise to them, we found that many storm surges during extreme sea level events were related to cyclones of only moderate intensity. Combined with the previous findings, this work suggests the need to assess extreme sea level return values for future construction and infrastructure planning as the result of a multi-variable system. This is in contrast to basing such assessments on the single variable of observed sea level as it is done today.</p>

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