scholarly journals Modeling dependence and coincidence of storm surges and high tide: methodology, discussion and recommendations based on a simplified case study in Le Havre (France)

2020 ◽  
Vol 20 (12) ◽  
pp. 3387-3398
Author(s):  
Amine Ben Daoued ◽  
Yasser Hamdi ◽  
Nassima Mouhous-Voyneau ◽  
Philippe Sergent
Keyword(s):  
Storm Surge ◽  
High Tide ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Dependence Structure ◽  
Probability Method ◽  
Sea Levels ◽  
Flooding Hazard ◽  
Extreme Sea Levels

Abstract. Coastal facilities such as nuclear power plants (NPPs) have to be designed to withstand extreme weather conditions and must, in particular, be protected against coastal floods because it is the most important source of coastal lowland inundations. Indeed, considering the combination of tide and extreme storm surges (SSs) is a key issue in the evaluation of the risk associated with coastal flooding hazard. Most existing studies are generally based on the assumption that high tides and extreme SSs are independent. While there are several approaches to analyze and characterize coastal flooding hazard with either extreme SSs or sea levels, only few studies propose and compare several approaches combining the tide density with the SS variable. Thus this study aims to develop a method for modeling dependence and coincidence of SSs and high tide. In this work, we have used existing methods for tide and SS combination and tried to improve the results by proposing a new alternative approach while showing the limitations and advantages of each method. Indeed, in order to estimate extreme sea levels, the classic joint probability method (JPM) is used by making use of a convolution between tide and the skew storm surge (SSS). Another statistical indirect analysis using the maximum instantaneous storm surge (MSS) is proposed in this paper as an alternative to the first method with the SSS variable. A direct frequency analysis using the extreme total sea level is also used as a reference method. The question we are trying to answer in this paper is then the coincidence and dependency essential for a combined tide and SS hazard analysis. The results brought to light a bias in the MSS-based procedure compared to the direct statistics on sea levels, and this bias is more important for high return periods. It was also concluded that an appropriate coincidence probability concept, considering the dependence structure between SSs, is needed for a better assessment of the risk using the MSS. The city of Le Havre in France was used as a case study. Overall, the example has shown that the return level (RL) estimates using the MSS variable are quite different from those obtained with the method using the SSSs, with acceptable uncertainty. Furthermore, the shape parameter is negative from all the methods with a much heavier tail when the SSS and the extreme sea levels (ESLs) are used as variables of interest.

scholarly journals Modelling dependence and coincidence of storm surges and high tide: Methodology and simplified case study in Le Havre (France)

2020 ◽  
Author(s):  
Amine Ben Daoued ◽  
Yasser Hamdi ◽  
Nassima Mouhous-Voyneau ◽  
Philippe Sergent
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Hazard Analysis ◽  
High Tide ◽  
Storm Surges ◽  
Weather Conditions ◽  
Coastal Flooding ◽  
Sea Levels ◽  
Flooding Hazard

Abstract. Coastal facilities such as nuclear power plants (NPPs) have to be designed to withstand extreme weather conditions and must, in particular, be protected against coastal floods because it is the most important source of coastal lowlands inundations. Indeed, considering the combination of tide and extreme storm surges (SSs) is a key issue in the evaluation of the risk associated to coastal flooding hazard. Tide and extreme SSs are considered as independent. While there are several approaches to analyze and characterize coastal flooding hazard with either extreme SSs or sea levels, only few studies propose and compare several approaches combining the tide density with the SS variable. Thus this study aims to develop a method for modelling dependence and coincidence of SSs and high tide. In this work, we have used existing methods for tide and SS combination and tried to improve the results by proposing a new alternative approach while showing the limitations and advantages of each method. The city of Le Havre in France was used as a case study. Overall, the example has shown that the return levels estimates using different combinations are quite different. It has also been suggested that the questions of coincidence and dependency are essential for a combined tide and SS hazard analysis.

scholarly journals Climate-induced storminess forces major increases in future storm surge hazard in the South China Sea region

2022 ◽  
Author(s):  
Melissa Wood ◽  
Ivan D. Haigh ◽  
Quan Quan Le ◽  
Hung Nghia Nguyen ◽  
Hoang Ba Tran ◽  
...  
Keyword(s):  
South China Sea ◽  
Storm Surge ◽  
South China ◽  
Storm Surges ◽  
The South China Sea ◽  
The South ◽  
Tropical Regions ◽  
Sea Levels ◽  
China Sea ◽  
Extreme Sea Levels

Abstract. It is vital to robustly estimate the risks posed by extreme sea levels, especially in tropical regions where cyclones can generate large storm surges and observations are too limited in time and space to deliver reliable analyses. To address this limitation for the South China Sea region, we force a hydrodynamic model with a new synthetic database representing 10,000 years of past/present and future tropical cyclone activity, to investigate climate change impacts on extreme sea levels forced by storm surges (± tides). We show that, as stronger and more numerous tropical cyclones likely pass through this region over the next 30 years, both the spatial extent and severity of storm surge hazard increases. While extreme storm surge events in this location become generally a more frequent occurrence in the future, larger storm surges around Vietnam and China coastlines are projected to regionally amplify this hazard. This threatens low-lying, densely-populated areas such as the Red and Mekong River deltas, while sections of the Cambodian and Thai coastline face previously unseen storm surge hazards. These future hazards strongly signal that coastal flood management and adaptation in these areas should be reviewed for their resilience against future extreme sea levels.

scholarly journals APPLICABILITY OF THE VERTICAL TELESCOPIC BREAKWATER USING THE PAST TYPHOON IN TOKYO BAY

2020 ◽  
pp. 35
Author(s):  
Yako Harada ◽  
Yukihisa Matsumoto ◽  
Kazuho Morishita ◽  
Nobuyuki Oonishi ◽  
Kazuyoshi Kihara ◽  
...  
Keyword(s):  
Climate Change ◽  
Storm Surge ◽  
Storm Surges ◽  
Numerical Calculations ◽  
Numerical Analyses ◽  
Tokyo Bay ◽  
Worst Case ◽  
Sea Levels ◽  
Long Period ◽  
The Past

The vertical telescopic breakwater(VTB), which is a new breakwater that permits the navigation of ships, remain at the bottom of the sea during calm and rise to the surface during tsunamis or storm surges. Kawai et al. (2017) and Arikawa et al. (2019) found that it is effective not only for swell waves, but also for long-period waves simulating tsunamis and storm surges by previous experiments and numerical analyses. However, there have been few studies on the performance of VTB by numerical calculations in actual ports using actual typhoons. In addition, sea levels and changes in characteristics of typhoon due to climate change are predicted to occur; hence, we are concerned about the damage in all quarters caused by storm surge inundation, especially at Tokyo. Therefore, in this study, we used hypothetical typhoons under worst-case scenarios and quantitatively evaluated the protection performance of VTB against hypothetical typhoons with different aperture rates of VTB in Tokyo Bay by the numerical simulation.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/qof5ixKqIiA

scholarly journals Projections of global-scale extreme sea levels and resulting episodic coastal flooding over the 21st Century

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ebru Kirezci ◽  
Ian R. Young ◽  
Roshanka Ranasinghe ◽  
Sanne Muis ◽  
Robert J. Nicholls ◽  
...  
Keyword(s):  
21St Century ◽  
Coastal Flooding ◽  
Global Scale ◽  
Sea Levels ◽  
Extreme Sea Levels

The dependence of UK extreme sea levels and storm surges on the North Atlantic Oscillation

2007 ◽  
Vol 27 (7) ◽  
pp. 935-946 ◽  
Author(s):  
P.L. Woodworth ◽  
R.A. Flather ◽  
J.A. Williams ◽  
S.L. Wakelin ◽  
S. Jevrejeva
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Storm Surges ◽  
Sea Levels ◽  
The North ◽  
Extreme Sea Levels ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Applying POT methods to the Revised Joint Probability Method for determining extreme sea levels

2014 ◽  
Vol 91 ◽  
pp. 140-150 ◽  
Author(s):  
Franck Mazas ◽  
Xavier Kergadallan ◽  
Philippe Garat ◽  
Luc Hamm
Keyword(s):  
Joint Probability ◽  
Probability Method ◽  
Sea Levels ◽  
Extreme Sea Levels ◽  
Joint Probability Method

What value do mangroves have in reducing the cost of storm surges?

2020 ◽  
Author(s):  
Christopher Thomas ◽  
Siddharth Narayan ◽  
Joss Matthewman ◽  
Christine Shepard ◽  
Laura Geselbracht ◽  
...  
Keyword(s):  
Storm Surge ◽  
Insurance Industry ◽  
Economic Value ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Economic Losses ◽  
Modelling Framework ◽  
Catastrophe Modelling ◽  
The Cost ◽  
The Impact

<p>With coastlines becoming increasingly urbanised worldwide, the economic risk posed by storm surges to coastal communities has never been greater. Given the financial and ecological costs of manmade coastal defences, the past few years have seen growing interest in the effectiveness of natural coastal “defences” in reducing the risk of flooding to coastal properties, but estimating their actual economic value in reducing storm surge risk remains a challenging subject.</p><p>In this study, we estimate the value of mangroves in reducing annual losses to property from storm surges along a large stretch of coastline in Florida (USA), by employing a catastrophe modelling approach widely used in the insurance industry. We use a hydrodynamic coastal flood model coupled to a property loss model and a large property exposure dataset to estimate annual economic losses from hurricane-driven storm surges in Collier County, a hurricane-prone part of Florida. We then estimate the impact that removing mangroves in the region would have on average annual losses (AAL) caused by coastal flooding. We find that mangroves reduce AAL to properties behind them by over 25%, and that these benefits are distributed very heterogeneously along the coastline. Mangrove presence can also act to enhance the storm surge risk in areas where development has occurred seaward of mangroves.</p><p>In addition to looking at annual losses, we also focus on the storm surge caused by a specific severe event in Florida, based on Hurricane Irma (2017), and we estimate that existing mangroves reduced economic property damage by hundreds of millions of USD, and reduced coastal flooding for hundreds of thousands of people.</p><p>Together these studies aim to financially quantify some of the risk reduction services provided by natural defences in terms of reducing the cost of coastal flooding, and show that these services can be included in a catastrophe modelling framework commonly used in the insurance industry.</p>

Supporting European coastal sectors to adapt to changes in extreme sea levels with climate change

2020 ◽  
Author(s):  
Sanne Muis ◽  
Maialen Irazoqui Apecechea ◽  
Job Dullaart ◽  
Joao de Lima Rego ◽  
Kristine S. Madsen ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Storm Surges ◽  
Climate Impact ◽  
Climate Impacts ◽  
Water Levels ◽  
Climate Data ◽  
Local Climate ◽  
Sea Levels ◽  
Extreme Sea Levels

<p>Climate change will lead to increases in the flood risk in low-lying coastal areas. Understanding the magnitude and impact of such changes is vital to design adaptive strategies and create awareness. In  the  context  of  the  CoDEC  project  (Coastal  Dataset  for  Evaluation  of  Climate  impact),  we  developed a consistent European dataset of extreme sea levels, including climatic changes from 1979 to 2100. To simulate extreme sea levels, we apply the Global Tide and Surge Model v3.0 (GTSMv3.0), a 2D hydrodynamic model with global coverage. GTSM has a coastal resolution of 2.5 km globally and 1.25 km in Europe, and incorporates dynamic interactions between sea-level  rise,  tides  and  storm surges. Validation of the dataset shows a good performance with a mean bias of 0-.04 m for the 1 in 10-year water levels. When analyzing changes in extreme sea levels for the future climate scenarios, it is projected that by the end of the century the 1 in 10-year water levels are likely to increase up to 0.5 m. This change is largely driven by the increase in mean sea levels, although locally changes in storms surge and interaction with tides can amplify the impacts of sea-level rise with changes up to 0.2 m in the 1 in 10-year water level.</p><p>The CoDEC dataset will be made accessible through a web portal on Copernicus Climate Data Store (C3S). The dataset includes a set of Climate Impact Indicators (CII’s) and new tools designed to evaluate the impacts of climate change on different sectors and industries. This data service will support European coastal sectors to adapt to changes in sea levels associated with climate change. In this presentation we will also demonstrate how the C3S coastal service can be used to enhance the understanding of local climate impacts.</p>

scholarly journals Baltic Sea coastal erosion; a case study from the Jastrzębia Góra region

Geologos ◽  
2014 ◽  
Vol 20 (4) ◽  
pp. 259-268 ◽  
Author(s):  
Grzegorz Uścinowicz ◽  
Regina Kramarska ◽  
Dorota Kaulbarsz ◽  
Leszek Jurys ◽  
Jerzy Frydel ◽  
...  
Keyword(s):  
Storm Surges ◽  
Hydrotechnical Construction ◽  
Aerial Photographs ◽  
Sea Levels ◽  
General Importance ◽  
Wave Effects ◽  
Active Landslide ◽  
Rising Sea Levels ◽  
Remote Sensing Methods

Abstract The coastline in the Jastrzębia Góra area can be divided into three major zones of general importance: a beach and barrier section, a cliff section, and a section protected by a heavy hydrotechnical construction. These areas are characterised by a diverse geology and origin, and hence different vulnerability to erosion. In addition, observations have demonstrated a different pace of erosion within each zone. Based on the results obtained by remote sensing methods (analysis of aerial photographs and maps), it has been determined that the coastline in the barrier area, i.e., to the west of Jastrzębia Góra, moved landwards by about 130 m, in a period of 100 years, and 80 m over about 50 years. A smaller displacement of the shoreline could be observed within the cliff. Between the middle of the twentieth and the start of the twenty-first centuries the shore retreated by about 25 m. However, in recent years, an active landslide has led to the displacement of the uppermost part of the cliff locally up to 25 m. Another issue is, functioning since 2000, a heavy hydrotechnical construction which has been built in order to protect the most active part of the cliff. The construction is not stable and its western part, over a distance of 50 m, has moved almost 2 m vertically downwards and c. 2.5 m horizontally towards the sea in the past two years. This illustrates that the erosional factor does not comprise only marine abrasion, but also involves land-based processes determined by geology and hydrogeology. Changes in the shoreline at the beach and barrier part are constantly conditioned by rising sea levels, the slightly sloping profile of the sea floor and low elevation values of the backshore and dune areas. Cliffs are destroyed by mass wasting and repetitive storm surges that are responsible for the removal of the colluvium which protects the coast from adverse wave effects. Presumably, mass movements combined with groundwater outflow from the cliff, plus sea abrasion cause destabilisation of the cliff protection construction.

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