Storm Tide and Wave Simulations and Assessment

In this Special Issue, seven high-quality papers covering the application and development of many high-end techniques for studies on storm tides, surges, and waves have been published, for instance, the employment of an artificial neural network for predicting coastal freak waves [1]; a reproduction of super typhoon-created extreme waves [2]; a numerical analysis of nonlinear interactions for storm waves, tides, and currents [3]; wave simulation for an island using a circulation–wave coupled model [4]; an analysis of typhoon-induced waves along typhoon tracks in the western North Pacific Ocean [5]; an understanding of how a storm surge prevents or severely restricts aeolian supply [6]; and an investigation of coastal settlements and an assessment of their vulnerability [7]

Response of the Coastal Ocean to Tropical Cyclones

The Northwest Pacific and the South China Sea region are the birthplaces of most monsoon disturbances and tropical cyclones and are an important channel for the generation and transmission of water vapor. The Northwest Pacific plays a major role in regulating interdecadal and long-term changes in climate. China experiences the largest number of typhoon landfalls and the most destructive power affected by typhoons in the world. The hidden dangers of typhoon disasters are accelerating with the acceleration of urbanization, the rapid development of economic construction and global warming. The coastal cities are the most dynamic and affluent areas of China’s economic development. They are the strong magnetic field that attracts international capital in China, and are also the most densely populated areas and important port groups in China. Although these regions are highly developed, they are vulnerable to disasters. When typhoons hit, the economic losses and casualties caused by gale, heavy rain and storm surges were particularly serious. This chapter reviews the response of coastal ocean to tropical cyclones, included sea surface temperature, sea surface salinity, storm surge simulation and extreme rainfall under the influence of tropical cyclones

Typhoon Wind Modeling and Flutter Fragility Analysis of Long-Span Bridges in Coastal Regions of China

Typhoon or hurricane or tropical cyclone, which is a large-scale air rotating system around a low atmospheric pressure center, frequently causing devastating economic loss and human casualties along coastal regions due to violent winds, heavy rainfall, massive storm surges, flash flooding or even landslides in mountainous areas. The coastal region of China, which is characterized by high population densities and well-developed cities, is always exposed to typhoon threats with 7~8 landfall typhoons every year since Western Pacific Basin is the most active typhoon basin on earth, accounting for almost one-third of global annual storms. With more long-span bridges are being constructed along this coastal area, it is of great importance to perform the risk assessments on these flexible or wind-sensitive structures subjected to typhoon winds. To reconstruct the mean typhoon wind speed field, a semi-analytical height-resolving typhoon boundary layer wind field model, including a parametric pressure model and an analytical wind model was first developed in Chapter 2 using a scale analysis technique. Some basic characteristics of the inner structure of typhoon wind field, such as the logarithmic vertical wind profile near the ground and super-gradient winds were reproduced. Then, Chapter 3 develops a dataset of two wind field parameters, i.e. the radius to maximum wind speed, R_(max,s) and the Holland pressure profile parameter, B_s in Western Pacific Ocean using the wind data information from best track dataset archived by the Japan Meteorological Agency (JMA) coupled with the present wind field model. The proposed dataset of R_(max,s) and B_s is able to reproduce the JMA wind observations as closely as possible, which allows performing more accurate typhoon wind hazard estimation. On this basis, the maximum wind hazard footprints for over-water, roughness only and roughness and topography combined conditions of 184 observed landed or offshore typhoon-scale storms are generated and archived for risk assessment. Moreover, this supplementary dataset of R_(max,s) and B_s enables the development of recursive models to facilitate both sub-region typhoon simulations and full track simulations. Since the present wind field model can only generate long-time-duration speed, say 10-min mean wind speed, Chapter 4 develops an algorithm to compute the gust factor curve by taking the non-stationary and non-Gaussian characteristics of typhoon winds into account. The real wind data of nine typhoons captured by the structural health monitoring system (SHMS) installed in Xihoumen Bridge were utilized to validate the proposed model. Then, the probability distributions of gust factor associated with any gust time duration of interest can be readily achieved after introducing the statistical models of skewness and kurtosis of typhoon winds. To predict the typhoon wind hazard along the coastal region of China, a geographically-weighted-regression (GWR) -based subregion model was proposed in Chapter 5. The storm genesis model was first applied to a circular boundary around the site of interest. Then, the typhoon forward model including the tracking model, intensity model, and wind field parameter model was developed utilizing the GWR method. A series of performance assessments were performed on the present subregion model before it was employed to predict the typhoon wind hazards around the coastal regions of China. Chapter 6 develops a framework to investigate the probabilistic solutions of flutter instability in terms of critical wind speed accounting for multiple resources of uncertainty to facilitate the development of the fragility curve of flutter issue of long-span bridges. The quantifications of structural uncertainties, as well as aerodynamic uncertainties or the randomness of flutter derivatives, were conducted using both literature survey and experimental methods. A number of probabilistic solutions of flutter critical wind speed for two bridges, say a simply supported beam bridge and the Jiangyin Suspension Bridge were achieved by introducing different sources of uncertainty utilizing both 2D step-by-step analysis and 3D multimode techniques. To examine the flutter failure probability of long-span bridge due to typhoon winds, a case study of a 1666-m-main-span suspension bridge located in the typhoon-prone region was performed. The fragility curves of this bridge in terms of critical wind speed and the typhoon wind hazards curves of the bridge site as the probability of occurrence with respect to any years of interest were developed, respectively by exploiting the techniques achieved in previous chapters. Then a limit state function accounting for the bridge-specific flutter capacity and the site-specific mean typhoon wind hazard as well as the gust factor effects was employed to determine the flutter failure probabilities utilizing Monte Carlo simulation approach

Proceedings Of The 18th Annual Meeting Of The Asia Oceania Geosciences Society (Aogs 2021)

The 18th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2021) was held from 1st to 6th August 2021. This proceedings volume includes selected extended abstracts from a challenging array of presentations at this conference. The AOGS Annual Meeting is a leading venue for professional interaction among researchers and practitioners, covering diverse disciplines of geosciences

Waves and Ocean Structures

Ocean Structures subjected to actions of ocean waves require safety inspection as they protect human environment and everyday lives. Increasing uses of ocean environment have brought active research activities continuously. The newly developed technology of ocean energy even pushed the related needs forward one more step. This Special Issue focuses on Analysis of Interactions between wave structures and ocean waves. Although ocean structures may cover various practical and/or conceptual types, we hope in the years to come, the state-of-the-art applications in wave and structure interactions and/or progress review and future developments could be included. There are fifteen papers published in the Special issue. A brief description includes: Lee et al. [1] presented a concept of a water column type wave power converter. Li et al. [2] considered submerged breakwaters. Lin et al. [3] studied an ocean current turbine system. Thiagarajan and Moreno [4] investigated oscillating heave plates in wind turbines. Chiang et al. [5] proposed an actuator disk model. Tseng et al. [6] investigated Bragg reflections of periodic surface-piercing submerged breakwaters. Lee et al. [7] analyzed caisson structures with a wave power conversion system installed. Yeh et al. [8] reported motion reduction in offshore wind turbines. Wu and Hsiao [9] considered submerged slotted barriers. Tang et al. [10] studied floating platforms with fishnets. Chen et al. [11] calculated mooring drags of underwater floating structures with moorings. Jeong et al. [12] estimated the motion performance of light buoys using ecofriendly and lightweight materials. Zhang et al. [13] considered vibrations of deep-sea risers. On the other hand, Shugan et al. [14] studied the effects of plastic coating on sea surfaces

CIRA annual report FY 2015/2016

Reporting period April 1, 2015-March 31, 2016

Enhancing storm surge resilience for coastal habitat: A framework to support sustainable development

More than 2.4 billion people live within 100 km of the sea coastline. Between 2016-2019 there has been a rising trend in tropical cyclone’s intensity and the frequency. Such cyclone events irrespective of their hurricane categorisation have persistently triggered coastal flooding such as storm surges of at least 7 ft (2 m). Over this period disaster losses from tropical cyclones have been estimated as US$ 343 billion, with over 3,333 deaths. A review of previous studies found that 47% of the Atlantic Cyclone’s deaths were caused by storm surges-triggered by hurricanes and not just by hurricanes themselves. The unique characteristics of storm surge and the uncertainty coupled with the lack of hurricane intensity prediction potentially leave coastal communities and the infrastructure directly exposed to the socioeconomic risk. The aim of this research is to develop a framework which helps enhance the resilience of coastal habitat to storm surge hazard. The proposed framework considers the adaptive capacity of developing countries, and its structure is developed by reviewing the current practices and strategies of disaster management for storm surge hazard triggered by tropical cyclones identifying the gaps and challenges. A framework approach could support the future resilience, reducing the disaster losses, both in terms of lives and in terms of socioeconomic, and environmental impacts of countries. This research fits within the wider knowledge field of disaster risk management and sustainable community’s enhancement adopts a qualitative exploratory research design based on case study methodology. The study focused on the implementation of four main disaster phases such as the (i) preparedness (ii) response (iii) recovery and (iv) mitigation of the disaster risk management (DRM) and disaster risk reduction (DRR) which had occurred from different events chosen for the case study and had occurred between 2000-2017. The examination of individual case studies and the cross-case syntheses of the cases resulted in identifying the commonalities and obtain insights into the DRM practices and governance in various countries. Gaps within current DRM strategies and their practices before, during and after the occurrence of the disaster were also identified which has assisted in the recommendations within this study. The findings then led to the proposal of the Disaster Adaptation to Mitigate Storm Surge (DAMSS) framework and guidelines for best practices. The findings and suggested approaches may also help governments, planners, engineers, builders, forecasters, emergency managers, relief workers, regional bodies, insurance, civil protection organisations, public and private officials of all the developing countries, to reduce future losses, where there is not the same supportive development infrastructure

Solar Power System Plaing & Design

Photovoltaic (PV) and concentrated solar power (CSP) systems for the conversion of solar energy into electricity are technologically robust, scalable, and geographically dispersed, and they possess enormous potential as sustainable energy sources. Systematic planning and design considering various factors and constraints are necessary for the successful deployment of PV and CSP systems. This book on solar power system planning and design includes 14 publications from esteemed research groups worldwide. The research and review papers in this Special Issue fall within the following broad categories: resource assessments, site evaluations, system design, performance assessments, and feasibility studies