scholarly journals INTER-COMPARISON OF COASTAL MODELS: CASE STUDY OF STORM SURGE AT NEMURO IN JAPAN

Author(s):  
Ryota Nakamura ◽  
Martin Mäll ◽  
Tomoya Shibayama ◽  
Shigeru Kato

The numerical coastal circulation models play an essential role in predicting storm surges. Several models (e.g. ADCIRC: Dietrich et al., 2004, FVCOM: Chen et al., 2003) have been previously inter-compared (Kerr et al., 2013; Chen et al., 2013). In these studies, storm surges were reproduced in locations where the bathymetry has a gradual increase from offshore to coast, within a closed gulf. On the other hand, there are few studies in regards to modelling storm surge where the near coast bathymetry is steep and connected to open ocean. Considering the storm surge dependence on local bathymetry, it can be important to conduct an inter-comparison of ocean circulation models in such a region. In this study, numerical coastal circulation models (2D-ADCIRC and 3D-FVCOM) are compared by using a 2014 Dec. storm surge event at Nemuro city in Hokkaido (Japan), which was caused by a rapidly intensified extra-tropical cyclone approaching the area. In this region, local bathymetry is steep due to Japan Trench. The cyclone caused a storm surge of nearly up to 1.8 m within the Nemuro city between 00:00 UTC 16th and 17th Dec. 2014. The aim of this study is to evaluate the performance of ocean circulation models using several air-sea drag coefficients and contribute to inter-comparison studies using ADCIRC and FVCOM.

2020 ◽  
Vol 20 (10) ◽  
pp. 2777-2790
Author(s):  
Xianwu Shi ◽  
Pubing Yu ◽  
Zhixing Guo ◽  
Zhilin Sun ◽  
Fuyuan Chen ◽  
...  

Abstract. China is one of the countries that is most seriously affected by storm surges. In recent years, storm surges in coastal areas of China have caused huge economic losses and a large number of human casualties. Knowledge of the inundation range and water depth of storm surges under different typhoon intensities could assist predisaster risk assessment and making evacuation plans, as well as provide decision support for responding to storm surges. Taking Pingyang County in Zhejiang Province as a case study area, parameters including typhoon tracks, radius of maximum wind speed, astronomical tide, and upstream flood runoff were determined for different typhoon intensities. Numerical simulations were conducted using these parameters to investigate the inundation range and water depth distribution of storm surges in Pingyang County considering the impact of seawall collapse under five different intensity scenarios (corresponding to minimum central pressure values equal to 915, 925, 935, 945, and 965 hPa). The inundated area ranged from 103.51 to 233.16 km2 for the most intense typhoon. The proposed method could be easily adopted in various coastal counties and serves as an effective tool for decision-making in storm surge disaster risk reduction practices.


2020 ◽  
Vol 8 (2) ◽  
pp. 335-350 ◽  
Author(s):  
Filipe Galiforni-Silva ◽  
Kathelijne M. Wijnberg ◽  
Suzanne J. M. H. Hulscher

Abstract. Growth of coastal dunes requires a marine supply of sediment. Processes that control the sediment transfer between the subtidal and the supratidal zone are not fully understood, especially in sand flats close to inlets. It is hypothesised that storm surge events induce sediment deposition on sand flats, providing fresh material for aeolian transport and dune growth. The objective of this study is to identify which processes cause deposition on the sand flat during storm surge conditions and discuss the relationship between the supratidal deposition and sediment supply to the dunes. We use the island of Texel (NL) as a case study, of which multiannual topographic and hydrographic datasets are available. Additionally, we use the numerical model XBeach to simulate the most frequent storm surge events for the area. Results show that supratidal shore-parallel deposition of sand occurs in both the numerical model and the topographic data. The amount of sand deposited is directly proportional to surge level and can account for more than a quarter of the volume deposited at the dunes yearly. Furthermore, storm surges are also capable of remobilising the top layer of sediment of the sand flat, making fresh sediment available for aeolian transport. Therefore, in a sand flat setting, storm surges have the potential of reworking significant amounts of sand for aeolian transport in periods after the storm and as such can also play a constructive role in coastal dune development.


Author(s):  
Justin Joseph Valdez ◽  
Tomoya Shibayama

In 2013 Typhoon Haiyan dealt strong winds and storm surges to Tacloban City, Philippines. After that, the standard public school buildings were designed using the load provisions of the updated 2015 National Structural Code of the Philippines. However, it is important to analyze if the school buildings can resist failure against another Haiyan storm surge event. Haiyan was simulated using the the Weather Research and Forecasting (WRF) Model, and the storm surge was simulated using the Finite Volume Community Ocean Model (FVCOM). The wind and flood loads were then calculated and applied on a two-story school building model in STAAD.Pro, and the maximum shear forces and bending moments in the 300 beams and columns were compared to its capacity.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/P3E1_aizbnE


2019 ◽  
Vol 7 (3) ◽  
pp. 77 ◽  
Author(s):  
Abram Musinguzi ◽  
Muhammad K. Akbar ◽  
Jason G. Fleming ◽  
Samuel K. Hargrove

Meteorological forcing is the primary driving force and primary source of errors for storm surge forecasting. The objective of this study was to learn how forecasted meteorological forcing influences storm surge generation and propagation during a hurricane so that storm surge models can be reliably used to forecast actual events. Hindcasts and forecasts of Hurricane Rita (2005) storm surge was used as a case study. Meteorological forcing or surface wind/pressure fields for Hurricane Rita were generated using both the Weather Research and Forecasting (WRF) full-scale forecasting model along with archived hurricane advisories ingested into a sophisticated parametric wind model, namely Generalized Asymmetric Holland Model (GAHM). These wind fields were used to forecast Rita storm surges. Observation based wind fields from the OceanWeather Inc. (OWI) Interactive Objective Kinematic Analysis (IOKA) model, and Best track wind data ingested into the GAHM model were used to generate wind fields for comparison purposes. These wind fields were all used to hindcast Rita storm surges with the ADvanced CIRCulation (ADCIRC) model coupled with the Simulating Waves Nearshore (SWAN) model in a tightly coupled storm surge-wave model referred to as ADCIRC+SWAN. The surge results were compared against a quality-controlled database of observed data to assess the performance of these wind fields on storm surge generation and propagation. The surge hindcast produced by the OWI wind field performed the best, although some high water mark (HWM) locations were overpredicted. Although somewhat underpredicted, the WRF wind fields forecasted wider surge extent and wetted most HWM locations. The hindcast using the Best track parameters in the GAHM and the forecast using forecast/advisories from the National Hurricane Center (NHC) in the GAHM produced strong and narrow wind fields causing localized high surges, which resulted in overprediction near landfall while many HWM locations away from wind bands remained dry.


Author(s):  
K. Preethi ◽  
P. L. N. Murty

<p><strong>Abstract.</strong> Tropical cyclones affect the east coast of India due to its distinctive topography which is formed with a network of estuaries, bays, rivers, and inlets that causes inland flooding. The inland inundation of sea water is inflicting severe damage to the life and property. The ocean water entering the beachfront zone results to storm surges. In order to mitigate these storm surges, real-time monitoring and warnings are essential. For better visualization and analyzing the outputs from storm surge models, efficient post-processing tools are required. Hence post-processing of storm surge using GIS is carried out for taking protective measures. Storm surge vulnerable locations along the east coast of India have been identified in perspective of the number of storm surge events. Blue Kenue and SMS softwares are used to generate the unstructured triangular mesh over the study domain. Cyclones Phailin and Hudhud are selected in the current study and the associated surge heights and inundation extents are examined.</p>


2020 ◽  
Vol 20 (12) ◽  
pp. 3387-3398
Author(s):  
Amine Ben Daoued ◽  
Yasser Hamdi ◽  
Nassima Mouhous-Voyneau ◽  
Philippe Sergent

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.


Author(s):  
Ryota Nakamura ◽  
Tomoya Shibayama

The object of this study is to evaluate an ensemble forecast of extreme storm surge by using a case of Typhoon Haiyan (2013) and its associated storm surge. A simple numerical model composed of ARW-WRF, FVCOM and SWAN is employed as a forecast system for storm surge. This ensemble system can successfully forecast storm surge 3-4 days before it happened. However, the typhoons in almost all ensemble members were underpredicted probably because of its difficulty in forecasting a track and central pressure of highly intense typhoon. This leads to the underestimation of a prediction of storm surges around Leyte Gulf. Compensating the underestimation of forecasted extreme storm surge, it can be important to not only examine the ensemble mean among members but also consider the phase-shifted manipulation and the worst ensemble member in the case where the extreme storm surge is forecasted. In addition, the ensemble forecast system can have a potential to determine the time at which the peak of extreme surge appears with a high precision.


Author(s):  
Rikito Hisamatsu ◽  
Rikito Hisamatsu ◽  
Kei Horie ◽  
Kei Horie

Container yards tend to be located along waterfronts that are exposed to high risk of storm surges. However, risk assessment tools such as vulnerability functions and risk maps for containers have not been sufficiently developed. In addition, damage due to storm surges is expected to increase owing to global warming. This paper aims to assess storm surge impact due to global warming for containers located at three major bays in Japan. First, we developed vulnerability functions for containers against storm surges using an engineering approach. Second, we simulated storm surges at three major bays using the SuWAT model and taking global warming into account. Finally, we developed storm surge risk maps for containers based on current and future situations using the vulnerability function and simulated inundation depth. As a result, we revealed the impact of global warming on storm surge risks for containers quantitatively.


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