Future Wave Climate Research Articles

Long-term time-dependent stochastic modelling of extreme waves

This paper presents a literature survey on time-dependent statistical modelling of extreme waves and sea states. The focus is twofold: on statistical modelling of extreme waves and space- and time-dependent statistical modelling. The first part will consist of a literature review of statistical modelling of extreme waves and wave parameters, most notably on the modelling of extreme significant wave height. The second part will focus on statistical modelling of time- and space-dependent variables in a more general sense, and will focus on the methodology and models used also in other relevant application areas. It was found that limited effort has been put on developing statistical models for waves incorporating spatial and long-term temporal variability and it is suggested that model improvements could be achieved by adopting approaches from other application areas. In particular, Bayesian hierarchical space–time models were identified as promising tools for spatio-temporal modelling of extreme waves. Finally, a review of projections of future extreme wave climate is presented.

Projection of Extreme Wave Climate Change under Global Warming

The influence of global climate change due to greenhouse effects on the earth’s environment will require impact assessment, mitigation and adaptation strategies for the future of our society. This study predicts future ocean wave climate in comparison with present wave climate based on the atmospheric general circulation model and global wave model. The annual averaged and extreme sea surface winds and waves are analyzed in detail. There are clear regional dependences of both annual average and also extreme wave height changes from present to future climates. The wave heights of future climate will increase at both middle latitudes and also in the Antarctic Ocean, with a decrease at the equator.

Projection of Extreme Waves under a Global Warming Scenario

The influence of global climate change due to green house effects on the earth environment will require impact assessment, mitigation and adaptation strategies for the future of our society. This study projects future extreme ocean wave climate in comparison with present wave climate based on the atmospheric general circulation model and global wave model. The extreme sea surface winds and waves are analyzed based on extreme value methods in detail. There is a clear regional dependence of extreme winds and wave heights changes from present to future climates. The extreme wave heights of future climate would be increased significantly in tropical cyclone areas.

Equilibrium shoreline response: Observations and modeling

Shoreline location and incident wave energy, observed for almost 5 years at Torrey Pines beach, show seasonal fluctuations characteristic of southern California beaches. The shoreline location, defined as the cross‐shore position of the mean sea level contour, retreats by almost 40 m in response to energetic winter waves and gradually recovers during low‐energy summer waves. Hourly estimates of incident wave energy and weekly to monthly surveys of the shoreline location are used to develop and calibrate an equilibrium‐type shoreline change model. By hypothesis, the shoreline change rate depends on both the wave energy and the wave energy disequilibrium with the shoreline location. Using calibrated values of four model free parameters, observed and modeled shoreline location are well correlated at Torrey Pines and two additional survey sites. Model free parameters can be estimated with as little as 2 years of monthly observations or with about 5 years of ideally timed, biannual observations. Wave energy time series used to calibrate and test the model must resolve individual storms, and model performance is substantially degraded by using weekly to monthly averaged wave energy. Variations of free parameter values between sites may be associated with variations in sand grain size, sediment availability, and other factors. The model successfully reproduces shoreline location for time periods not used in tuning and can be used to predict beach response to past or hypothetical future wave climates. However, the model will fail when neglected geologic factors are important (e.g., underlying bedrock limits erosion or sand availability limits accretion).

Future wind, wave and storm surge climate in the Northern Seas: a revisit

Future wind, wave and storm surge climate in the Northern Seas: a revisit

Future wind, wave and storm surge climate in the Northern Seas: a revisit

We consider possible changes in the future climate of wind speed (WS), significant wave height (SWH) and storm surge residual (SSR) for a region covering the Northern Seas. Our results are based on an analysis of changes in the response derived with regional atmosphere, wave, and storm surge models run for two time periods 1961–1990 and 2071–2100. Available for the study were atmospheric downscalings of the Hadley Centre’s SRES A2 and B2 scenarios, the Max-Planck Institute’s SRES B2 scenario and the Bjerknes Centre’s SRES A1B scenario. The most important statistically significant findings are, first, a decrease in WS south of Iceland accompanied by a decrease of about 4–6% in SWH. Secondly, there is an increase in the eastern North Sea that continues into the Skagerrak. Along the North Sea east coast and in the Skagerrak the annual 99-percentiles of SWH and SSR increase 6–8% and 8–10%, respectively, and these results are robust across the various choices in global models and emission scenarios. Finally, there is an increase in the annual 99-percentiles of all variables west of the British Isles.

Future wind, wave and storm surge climate in the Northern Seas: a revisit

We consider possible changes in the future climate of wind speed (WS), significant wave height (SWH) and storm surge residual (SSR) for a region covering the Northern Seas. Our results are based on an analysis of changes in the response derived with regional atmosphere, wave, and storm surge models run for two time periods 1961–1990 and 2071–2100. Available for the study were atmospheric downscalings of the Hadley Centre’s SRES A2 and B2 scenarios, the Max-Planck Institute’s SRES B2 scenario and the Bjerknes Centre’s SRES A1B scenario.The most important statistically significant findings are, first, a decrease in WS south of Iceland accompanied by a decrease of about 4–6% in SWH. Secondly, there is an increase in the eastern North Sea that continues into the Skagerrak. Along the North Sea east coast and in the Skagerrak the annual 99-percentiles of SWH and SSR increase 6–8% and 8–10%, respectively, and these results are robust across the various choices in global models and emission scenarios. Finally, there is an increase in the annual 99-percentiles of all variables west of the British Isles.

Future wind, wave and storm surge climate in the northern North Atlantic

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 23:39-49 (2002) - doi:10.3354/cr023039 Future wind, wave and storm surge climate in the northern North Atlantic Jens Debernard*, Øyvind Sætra, Lars Petter Røed Research and Development Division, Norwegian Meteorological Institute, PO Box 43, Blindern, 0313 Oslo, Norway *Email: jens.debernard@met.no ABSTRACT: In this paper we consider a possible change in future wind, wave, and storm surge climate for the regional seas northeast of the Atlantic: the northern North Atlantic. Conclusions are based on a statistical analysis of the results derived with state-of-the-art wave and storm surge models run for two 20 yr time-slice periods, one for the period 1980 to 2000 (control climate) and one for the period 2030 to 2050 (future climate). Forcing was derived by extracting atmospheric wind and sea level pressure from a state-of-the-art regional atmospheric climate model for the same two 20 yr periods. These regional atmospheric simulations constitute dynamical downscales of the Max Planck Institute¹s global scenario which includes greenhouse gases, sulphate aerosols (direct and indirect effects) and tropospheric ozone. Generally the changes we found are small. However, there are some important exceptions, such as a significant increase in all variables in the Barents Sea and a significant reduction in wind and waves north and west of Iceland. Also, there is a significant increase in wind speed in the northern North Sea and westwards in the Atlantic Ocean, and a comparable reduction southwest of the British Isles in the autumn. The same change is suggested for wave height, but this is not statistically significant. There is a significant increase in the seasonal 99 percentile of the sea level in autumn in the southwest part of the North Sea. These results are consistent with earlier studies predicting a rougher maritime climate in the northern North Sea in autumn. KEY WORDS: Dynamical downscaling · Sea state · Climate change · Wave climate · Surge climate Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 23, No. 1. Online publication date: December 20, 2002 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2002 Inter-Research.

5508013 Process for the production of sulphur from at least one sour gas containing hydrogen sulphide and a fuel effluent and thermal reactor

Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future. To elucidate how these processes may respond to climate change, extreme boreal winter and summer wave conditions under future sea-level rise (SLR) and wave climate scenarios were simulated at two atolls, Wake and Midway, using a shallow-water hydrodynamic model. Nearshore wave conditions were used to compute the potential longshore sediment flux along island shorelines via the CERC empirical formula and wave-driven erosion was calculated as the divergence of the longshore drift; run-up and the locations where the run-up exceed the berm elevation were also determined. SLR is projected to predominantly drive future island morphological change and flooding. Seaward shorelines (i.e., ocean fronted shorelines directly facing incident wave energy) were projected to experience greater erosion and flooding with SLR and in hypothetical scenarios where changes to deep water wave directions were altered, as informed by previous climate change forced Pacific wave modeling efforts. These changes caused nearshore waves to become more shore-normal, increasing wave attack along previously protected shorelines. With SLR, leeward shorelines (i.e., an ocean facing shoreline but sheltered from incident wave energy) became more accretive on windward islands and marginally more erosive along leeward islands. These shorelines became more accretionary and subject to more flooding with nearshore waves becoming more shore-normal. Lagoon shorelines demonstrated the greatest SLR-driven increase in erosion and run-up. They exhibited the greatest relative change with increasing wave heights where both erosion and run-up magnitudes increased. Wider reef flat-fronted seaward shorelines became more accretive as all oceanographic forcing parameters increased in magnitude and exhibited large run-up increases following increasing wave heights. Island end shorelines became subject to increased flooding, erosion at Wake, and accretion at Midway with SLR. Under future conditions, windward and leeward islands are projected to become thinner as ocean facing and lagoonal shorelines erode, with leeward islands becoming more elongate. Island shorelines will change dramatically over the next century as SLR and altered wave climates drive new erosional regimes. It is vital to the sustainability of island communities that the relative magnitudes of these effects are addressed when planning for projected future climates.