Consequences of Wave Climate Change for Tanker Design

AbstractExtreme waves will undergo changes in the future when exposed to different climate change scenarios. These changes are evaluated through the analysis of significant wave height (Hs) return values and are also compared with annual mean Hs projections. Hourly time series are analyzed through a seven-member ensemble of wave climate simulations and changes are estimated in Hs for return periods from 5 to 100 years by the end of the century under RCP4.5 and RCP8.5 scenarios. Despite the underlying uncertainty that characterizes extremes, we obtain robust changes in extreme Hs over more than approximately 25% of the ocean surface. The results obtained conclude that increases cover wider areas and are larger in magnitude than decreases for higher return periods. The Southern Ocean is the region where the most robust increase in extreme Hs is projected, showing local increases of over 2 m regardless the analyzed return period under RCP8.5 scenario. On the contrary, the tropical north Pacific shows the most robust decrease in extreme Hs, with local decreases of over 1.5 m. Relevant divergences are found in several ocean regions between the projected behavior of mean and extreme wave conditions. For example, an increase in Hs return values and a decrease in annual mean Hs is found in the SE Indian, NW Atlantic and NE Pacific. Therefore, an extrapolation of the expected change in mean wave conditions to extremes in regions presenting such divergences should be adopted with caution, since it may lead to misinterpretation when used for the design of marine structures or in the evaluation of coastal flooding and erosion.

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Statistical Analysis on the Extreme Events of Big Waves Under Wave Climate Change Around Taiwan Waters

Volume 6: Ocean Engineering ◽

10.1115/omae2011-49896 ◽

2011 ◽

Author(s):

Ching-Her Hwang ◽

Wen-Ching Lee ◽

Wen-Fang Hsieh ◽

Ching-Piao Tsai ◽

Hwa Chien

Keyword(s):

Climate Change ◽

Wave Field ◽

Extreme Events ◽

Wind Field ◽

Wave Climate ◽

Model Parameters ◽

Climate Change Research ◽

Weather Bureau ◽

Central Weather Bureau ◽

Typhoon Wind

This study aimed to analyze the statistical characteristics of wave heights, wave energy and wave steepness, in order to investigate the wave climate changes around Taiwan Waters, especially for extreme events of big waves. The operational observation of Taiwan sea waves was initiated by the Central Weather Bureau in 1998; however, due to insufficient data length and low data space coverage, the data are unable to serve as references for long-term wave climate change research. Hence, this study adopted the SWAN (Simulation of Wave in Nearshore) Numerical Wave Hindcasting Method, which is a common method used in many studies, to hindcast the history of a wave field. The re-analysis on wind field data of the last 60 years (1948∼2008), published by the National Centers for Environmental Prediction (NCEP), was employed to make the wind field grid consistent with the hindcast wave field grid. Moreover, the Typhoon Wind Field Grid Down Scaling technique proposed by Winter & Chiou (2007) was applied to interpolate a U10 analysis field that better fits an actual typhoon wind field. The hindcast wave data were compared and validated with directional spectra, which were observed by the meteorological/oceanographic data buoys set up by the Central Weather Bureau and Water Resources Agency since 1997. Longdong, Hualien and Hsinchu Stations were chosen to represent the wave characteristics of sea areas around the island of Taiwan. According to observation data, model parameters were adjusted so that the hindcast results could be closer to observed data in Taiwan sea areas.

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Complex coastlines responding to climate change: do shoreline shapes reflect present forcing or "remember" the distant past?

10.5194/esurf-2016-35 ◽

2016 ◽

Author(s):

Christopher W. Thomas ◽

A. Brad Murray ◽

Andrew D. Ashton ◽

Martin D. Hurst ◽

Andrew K. A. P. Barkwith ◽

...

Keyword(s):

Climate Change ◽

Wave Climate ◽

Quasi Equilibrium ◽

Morphological Response ◽

Antecedent Conditions ◽

Coastline Evolution ◽

Aspect Ratios ◽

Order Of Magnitude ◽

Offshore Wave ◽

Hysteresis Behaviour

Abstract. A range of planform morphologies emerge along sandy coastlines as a function of offshore wave climate. It has been implicitly assumed that the morphological response time is rapid compared to the time scales of wave-climate change, meaning that coastal morphologies simply reflect the extant wave climate. This assumption has been explored by focussing on the response of two distinctive morphological coastlines – flying spits and cuspate cusps – to changing wave climates, using a coastline evolution model. Results indicate that antecedent conditions are important in determining the evolution of morphologies, and that sandy coastlines can demonstrate hysteresis behaviour. In particular, antecedent morphology is particularly important in the evolution of flying spits, with characteristic timescales of morphological adjustment on the order of centuries for large spits. Characteristic timescales vary with the square of aspect ratios of capes and spits; for spits, these timescales are an order of magnitude longer than for capes (centuries vs. decades). When wave climates change more slowly than the relevant characteristic timescales, coastlines are able to adjust in a quasi-equilibrium manner. Our results have important implications for the management of sandy coastlines where decisions may be implicitly and incorrectly based on the assumption that present-day coastlines are in equilibrium with current conditions.

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Impacts of Climate Change on Extreme Wave Climate Along the Western Coast of Sri Lanka

Coastal Management ◽

10.1680/cm.61149.119 ◽

2016 ◽

Author(s):

R. M. J. Bamunawala ◽

S. S. L. Hettiarachchi ◽

S. P. Samarawickrama ◽

P. N. Wikramanayake ◽

Roshanka Ranasinghe

Keyword(s):

Climate Change ◽

Sri Lanka ◽

Wave Climate ◽

Western Coast ◽

Extreme Wave ◽

Impacts Of Climate Change

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Wave climate change in the Gulf of Bothnia

10.5194/egusphere-egu21-9808 ◽

2021 ◽

Author(s):

Jan-Victor Björkqvist ◽

Jani Särkkä ◽

Hedi Kanarik ◽

Laura Tuomi

Keyword(s):

Climate Change ◽

Wave Model ◽

Wave Climate ◽

Atmospheric Forcing ◽

Simulation Data ◽

Significant Wave ◽

Gulf Of Bothnia ◽

Wave Heights ◽

Significant Wave Heights ◽

Projected Changes

<p>Wave climate change in the Gulf of Bothnia in 2030&#8211;2059 was investigated using regional wave climate projections. For the simulations we used wave model WAM. As the atmospheric forcing for the wave model we had three global climate scenarios (HADGEM2-ES, MPI-ESM, EC-EARTH) downscaled with RCA4-NEMO regional model. The ice concentration for the wave model was obtained from NEMO ocean model simulations using the same atmospheric forcing. We used both RCP4.5 and RCP8.5 greenhouse gas scenarios. The spatial resolution of the simulation data was 1.8 km, enabling detailed analyses of the wave properties near the coast. From the simulation data we calculated statistics and return levels of significant wave heights using extreme value analysis, and assessed the projected changes in the wave climate in the Gulf of Bothnia. The projected increase in the significant wave heights is mainly due to the decreasing ice cover, especially in the Bothnian Bay. Projected changes in the most prevalent wind direction impacts the spatial pattern of the wave heights in the Bothnian Sea.</p>

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Investigation of long-term changes of coastal wave directionality patterns and their connections with NAO climatic index: UK case study

10.5194/egusphere-egu21-16438 ◽

2021 ◽

Author(s):

Antonia Chatzirodou

Keyword(s):

Climate Change ◽

Flood Risk ◽

Wave Climate ◽

Wave Direction ◽

Climatic Index ◽

Coastal Flood ◽

Time Period ◽

Wave Directionality ◽

Coastal Flood Risk ◽

Offshore Wave

<p>The effects of climate change are at the spotlight of scientific research. In coastal science the effects of sea-level rise (SLR) on coastal areas, mainly as a result of melting of ice sheets and thermal volume expansion consist an intensive area of research. As well the changing ocean wave field due to greenhouse effect and interactions of atmospheric processes is under investigation. Researchers have placed focus on significant wave height changes and their associated impacts on the coastal environment, with evidence suggesting that the number, intensity and location of storms will change. It is suggested that equal attention should be placed on the mean wave direction changes and the effects that these changes may have on the coastlines and surrounding coastal infrastructure. Following that, this study investigated the changes in wave direction data since 1979 to 2019 covering 40 years&#8217; time period at 11 offshore UK coastal locations. The selected locations lie close to WaveNet, Cefas&#8217; strategic wave monitoring network points for the UK. Stakeholders use the data to provide advice and guidance to all involved parties including responders and communities about coastal flood risk. On a longer timescale the data provide evidence to coastal engineers and scientists of the wave climate change patterns and the implications this may have on coastal structures and flood defences design. Based on this initiative, this study investigated UK offshore wave climate changes by performing a longer timescale analysis of changes of wave direction patterns. The wave direction data were taken from ECMWF ERA5 6-hour hind cast data catalogue which covers 40 years&#8217; time period from 1797-2019 (Copernicus Climate Change Service (C3S), 2017). MATLAB software coding was primarily utilized for data processing and analyses. Following that, inferential statistics were applied to map inter-decadal statistical changes in wave direction patterns, suggesting that wave directionality patterns have presented changes at 11 offshore locations tested. &#160;The connections of wave directions with North Atlantic Oscillation (NAO) Climatic Index are currently investigated through use of machine learning approaches. The results of this study can be confidently used in wave transformation computational models coupled with hydro-morphodynamic models to downscale offshore wave direction changes to UK coastal areas. This can help identify susceptible coasts to offshore wave climate change. Susceptibility is regarded in form of coastal erosion and accretion rates changes as a result of altered offshore wave conditions, which might affect coastal flood risk with potential impacts on critical infrastructure. &#160;</p>

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Impact of Climate Change on Nearshore Waves at a Beach Protected by a Barrier Reef

Water ◽

10.3390/w12061681 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1681

Author(s):

Claude la Hausse de Lalouvière ◽

Vicente Gracia ◽

Joan Pau Sierra ◽

Jue Lin-Ye ◽

Manuel García-León

Keyword(s):

Climate Change ◽

Coral Reef ◽

Extreme Event ◽

Wave Climate ◽

Water Levels ◽

Barrier Reef ◽

Protective Capacity ◽

Protective Function ◽

Climate Change Effects ◽

Nearshore Waves

Barrier reefs dissipate most incoming wind-generated waves and, as a consequence, regulate the morphodynamics of its inbounded shorelines. The coastal protective capacity of reefs may nevertheless be compromised by climate change effects, such as reef degradation and sea-level rise. To assess the magnitude of these climate change effects, an analysis of the waves propagating across the barrier reef is carried out in Flic-en-Flac beach, Mauritius, based on scenarios of future sea levels and predicted coral reef condition. In the study, both the mean wave climate and extreme event conditions are considered. The results show that lower coral structure complexity jointly with higher water levels allow for higher waves to pass over the reef and, therefore, to reach the shoreline. In addition, modeling for cyclonic conditions showed that nearshore waves would also increase in height, which could lead to major coastal morphodynamic changes. Measures aimed at preserving the coral reef may allow the system to accommodate for the gradual climatic changes forecasted while keeping its coastal protective function.

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