BASIC STUDY ON ESTIMATION METHOD OF RETURN PERIOD AND VARIATION RANGE OF SEVERE STORM SURGE EVENT

Abstract. The possibility of utilising statistical dependence methods in coastal flood hazard calculations is investigated, since flood risk is rarely a function of just one source variable but usually two or more. Source variables in most cases are not independent as they may be driven by the same weather event, so their dependence, which is capable of modulating their joint return period, has to be estimated before the calculation of their joint probability. Dependence and correlation may differ substantially from one another since dependence is focused heavily on tail (extreme) percentiles. The statistical analysis between surge and wave is performed over 32 river ending points along European coasts. Two sets of almost 35-year hindcasts of storm surge and wave height were adapted and results are presented by means of analytical tables and maps referring to both correlation and statistical dependence values. Further, the top 80 compound events were defined for each river ending point. Their frequency of occurrence was found to be distinctly higher during the cold months while their main low-level flow characteristics appear to be mainly in harmony with the transient nature of storms and their tracks. Overall, significantly strong values of positive correlations and dependencies were found over the Irish Sea, English Channel, south coasts of the North Sea, Norwegian Sea and Baltic Sea, with compound events taking place in a zero-lag mode. For the rest, mostly positive moderate dependence values were estimated even if a considerable number of them had correlations of almost zero or even negative value.

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SENSITIVITY OF TROPICAL CYCLONE TRACK TO ASSESSMENT OF SEVERE STORM SURGE EVENT AT TOKYO BAY

Coastal Engineering Proceedings ◽

10.9753/icce.v36.papers.5 ◽

2018 ◽

pp. 5 ◽

Cited By ~ 3

Author(s):

Sota Nakajo ◽

Hideyuki Fujiki ◽

Sooyoul Kim ◽

Nobuhito Mori

Keyword(s):

Risk Assessment ◽

Storm Surge ◽

Wave Equations ◽

Tokyo Bay ◽

Cyclone Track ◽

Tropical Cyclone Track ◽

Translation Speed ◽

Long Wave ◽

Storm Surge Event ◽

Surge Height

In total 82 tropical cyclones data was used to determine scenarios of translation speed, minimum central pressure and track for risk assessment of storm surge at Tokyo Bay. The numerical simulation of waves and flows was conducted by solving non-linear long wave equations. The maximum surge height shows that the typhoon passing through along northeast directional track is dangerous for Tokyo Bay. This trend confirms the previous risk assessment was reasonable. However, it has been shown that the typhoon passing through along north directional track is also dangerous although the frequency is low. Especially, it is interesting that the typhoon passing through along northwest directional track causes distinctive resurgence and harbor oscillation.

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Uncertainty in coastal flooding: modelling and visualisation

10.5194/egusphere-egu2020-8390 ◽

2020 ◽

Author(s):

John Maskell

Keyword(s):

Water Level ◽

Storm Surge ◽

Return Period ◽

Flood Risk ◽

High Water ◽

Coastal Flooding ◽

Water Levels ◽

Tidal Range ◽

The Uk ◽

Flood Maps

Two case studies are considered in the UK, where uncertainty and drivers of coastal flood risk are explored through modelling and visualisations. Visualising the impact of uncertainty is a useful way of explaining the potential range of predicted or simulated flood risk to both expert and non-expert stakeholders.Significant flooding occurred in December 2013 and January 2017 at Hornsea on the UK East Coast, where storm surge levels and waves overtopped the town&#8217;s coastal defences. Uncertainty in the potential coastal flooding is visualised at Hornsea due to the range of uncertainty in the 100-year return period water level and in the calculated overtopping due to 3 m waves at the defences. The range of uncertainty in the simulated flooding is visualised through flood maps, where various combinations of the uncertainties decrease or increase the simulated inundated area by 58% and 82% respectively.Located at the mouth of the Mersey Estuary and facing the Irish Sea, New Brighton is affected by a large tidal range with potential storm surge and large waves. Uncertainty in the coastal flooding at the 100-year return period due to the combination of water levels and waves is explored through Monte-Carlo analysis and hydrodynamic modelling. Visualisation through flood maps shows that the inundation extent at New Brighton varies significantly for combined wave and surge events with a joint probability of 100 years, where the total flooded area ranges from 0 m2 to 10,300 m2. Waves are an important flood mechanism at New Brighton but are dependent on high water levels to impact the coastal defences and reduce the effective freeboard. The combination of waves and high-water levels at this return level not only determine the magnitude of the flood extent but also the spatial characteristics of the risk, whereby flooding of residential properties is dominated by overflow from high water levels, and commercial and leisure properties are affected by large waves that occur when the water level is relatively high at the defences.

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An Estimation Method for Potential Maximum Storm Surge Heights Using a New Tropical Cyclone Initialization Scheme and a Coupled Atmosphere-Ocean-Wave Model

Solutions to Coastal Disasters 2008 ◽

10.1061/40968(312)23 ◽

2008 ◽

Author(s):

Jun Yoshino ◽

Tomokazu Murakami ◽

Kosuke Kobayashi ◽

Takashi Yasuda

Keyword(s):

Tropical Cyclone ◽

Storm Surge ◽

Estimation Method ◽

Wave Model ◽

Ocean Wave ◽

Ocean Wave Model ◽

Initialization Scheme ◽

Potential Maximum ◽

Tropical Cyclone Initialization

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A New Physical Mechanism of the Storm Surge Event Generated by the Onshore Ekman Transport in the Deep Open Sea

PROCEEDINGS OF COASTAL ENGINEERING JSCE ◽

10.2208/proce1989.54.271 ◽

2007 ◽

Vol 54 ◽

pp. 271-275 ◽

Cited By ~ 1

Author(s):

Koji HASHIMOTO ◽

Jun YOSHINO ◽

Tomokazu MURAKAMI ◽

Takashi YASUDA

Keyword(s):

Storm Surge ◽

Physical Mechanism ◽

Ekman Transport ◽

Open Sea ◽

Storm Surge Event

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Assessing and zoning of typhoon storm surge risk with a geographic information system (GIS) technique: a case study of the coastal area of Huizhou

Natural Hazards and Earth System Science ◽

10.5194/nhess-21-439-2021 ◽

2021 ◽

Vol 21 (1) ◽

pp. 439-462

Author(s):

Si Wang ◽

Lin Mu ◽

Zhenfeng Yao ◽

Jia Gao ◽

Enjin Zhao ◽

...

Keyword(s):

Information System ◽

High Risk ◽

Storm Surge ◽

Return Period ◽

Coastal Area ◽

Guangdong Province ◽

High Population Density ◽

Typhoon Intensity ◽

Risk Maps ◽

Very High

Abstract. Storm surge is one of the most destructive marine disasters to life and property for Chinese coastal regions, especially for Guangdong Province. In Huizhou city, Guangdong Province, due to the high concentrations of chemical and petroleum industries and the high population density, the low-lying coastal area is susceptible to the storm surge. Therefore, a comprehensive risk assessment of storm surge over the coastal area of Huizhou can delimit zones that could be affected to reduce disaster losses. In this paper, typhoon intensity for the minimum central pressure of 880, 910, 920, 930, and 940 hPa (corresponding to a 1000-, 100-, 50-, 20-, and 10-year return period) scenarios was designed to cover possible situations. The Jelesnianski method and the Advanced Circulation (ADCIRC) model coupled with the Simulating Waves Nearshore (SWAN) model were utilized to simulate inundation extents and depths of storm surge over the computational domain under these representative scenarios. Subsequently, the output data from the coupled simulation model (ADCIRC–SWAN) were imported to the geographic information system (GIS) software to conduct the hazard assessment for each of the designed scenarios. Then, the vulnerability assessment was made based on the dataset of land cover types in the coastal region. Consequently, the potential storm surge risk maps for the designed scenarios were produced by combining hazard assessment and vulnerability assessment with the risk matrix approach. The risk maps indicate that due to the protection given by storm surge barriers, only a small proportion of the petrochemical industrial zone and the densely populated communities in the coastal areas were at risk of storm surge for the scenarios of 10- and 20-year return period typhoon intensity. Moreover, some parts of the exposed zone and densely populated communities were subject to high and very high risk when typhoon intensities were set to a 50- or a 100-year return period. Besides, the scenario with the most intense typhoon (1000-year return period) induced a very high risk to the coastal area of Huizhou. Accordingly, the risk maps can help decision-makers to develop risk response plans and evacuation strategies in coastal communities with a high population density to minimize civilian casualties. The risk analysis can also be utilized to identify the risk zones with the high concentration of chemical and petroleum industries to reduce economic losses and prevent environmental damage caused by the chemical pollutants and oil spills from petroleum facilities and infrastructures that could be affected by storm surge.

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