Impacts of climate change on wave regimes in the east sea (original) (raw)
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IMPACT OF GLOBAL CLIMATE CHANGE ON WAVE CLIMATE
Proceedings of Coastal Dynamics 2009 - Impacts of Human Activities on Dynamic Coastal Processes, 2009
The influence of global climate change due to green house effects on the earth environment will be required impact assessment, mitigation and adaptation strategies for future 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 dependence of annual average and extreme value from present to future climate. The wind speeds and wave heights of future climate are increased in middle latitudes and the Antarctic ocean, and these are decreased in the equator. The annual averaged winds and waves are decreased off coast of Japan but their maxima are increased than those of present climate.
Wave climate simulation for southern region of the South China Sea
Ocean Dynamics, 2013
This study investigates long-term variability and wave characteristic trends in the southern region of the South China Sea (SCS). We implemented the state-of-the art WAVEWATCH III spectral wave model to simulate a 31year wave hindcast. The simulation results were used to assess the inter-annual variability and long-term changes in the SCS wave climate for the period 1979 to 2009. The model was forced with Climate Forecast System Reanalysis winds and validated against altimeter data and limited available measurements from an Acoustic Wave and Current recorder located offshore of Terengganu, Malaysia. The mean annual significant wave height and peak wave period indicate the occurrence of higher wave heights and wave periods in the central SCS and lower in the Sunda shelf region. Consistent with wind patterns, the wave direction also shows southeasterly (northwesterly) waves during the summer (winter) monsoon. This detailed hindcast demonstrates strong inter-annual variability of wave heights, especially during the winter months in the SCS. Significant wave height correlated negatively with Niño3.4 index during winter, spring and autumn seasons but became positive in the summer monsoon. Such correlations correspond well with surface wind anomalies over the SCS during El Nino events. During El Niño Modoki, the summer time positive correlation extends northeastwards to cover the entire domain. Although significant positive trends were found at 95 % confidence levels during May, July and September, there is significant negative trend in December covering the Sunda shelf region. However, the trend appears to be largely influenced by large El Niño signals.
Assessment of potential wave power along a coastal province, Central Vietnam
International Marine Energy Journal
The potential wave power has been assessed based on long-term wave data along a marginal sea area offshore Phu Yen province in Central Vietnam. Based on the publicly available WaveWatch-III reanalysis wave data (NOAA), the deep-water wave climate during the period from 1989 to 2019 has been analysed and used as the boundary condition for the MIKE21 spectral wave model. The hydrodynamic module of MIKE21 is also run in coupled mode. The model has been calibrated and verified against the measured data at three wave gauges. Simulation has been performed for every month, each with 1-2 typical wave conditions. The results show that the highest wave power (~29 kW/m) occurs in December. The distribution of wave power along the 30-m depth contour has also been presented for the annual average, NE monsoon (winter) average, and S monsoon (summer) average. The distribution map shows that wave power is slightly higher in the south of this area, and the NE monsoon season comes along with much hig...
Assessment of Future Wave Climate on basis of Wind-Wave- Correlations and Climate Change Scenarios
Consequences resulting from future climate change may be one of the most severe threats for people and economies in many countries of the world. With respect to coastal protection, the resulting changed hydrodynamic impacts are discussed globally. At present, IPCC (2007) is estimating a world-wide average sea level rise of less than 1.0m within the 21st century. Other sources (e.g. Rahmstorf & Schellnhuber, 2007) which are taking into account possible melting of the two main continental ice covers (Greenland and Antarctica), estimate significantly higher values especially over long periods. Besides the problem of sea level rise, also possible general changes of the local wave conditions are described. The model results indicate a small increase of the overall wave energy input for the future and a more significant change in the wave directions where westerly wave conditions may increase by 3.5% compared to the actual conditions.
Modelling the effect of climate change on the wave climate of the world’s oceans
Ocean Science Journal, 2012
This paper analyses the trends and the future projections of significant wave height in several ocean areas at different parts of the world. It uses a stochastic Bayesian hierarchical space-time model, with a regression component with atmospheric levels of CO 2 as covariates in order to estimate the expected long-term trends and make future projections towards the year 2100. The model was initially developed for an area in the North Atlantic ocean, and has been found to perform reasonably well there, and it is now investigated how the model performs for other ocean areas. 11 new ocean areas have been analysed with the model, and this paper presents the results pertaining to the estimated long-term trends and future projections of monthly maximum significant wave height for each of the 12 ocean areas.
Monthly Variations of Global Wave Climate due to Global Warming
Jurnal Teknologi, 2015
Over recent years, ocean wave climate change due to global warming has attracted a lot of attention not only coastal and offshore engineer but also stakeholders in the marine industry. There is a wide range of application in ocean environment that require information on ocean wave climate data, such as ships design, design of offshore platforms and coastal structures or naval industry. In this research, monthly variation in significant wave height is studied using MRI-AGCM3.2 wind climate data for 25 year period from 1979-2003. The 25 year significant wave height simulation derived from JMA/MRI-AGCM wind climate data. The JMA/MRI-AGCM climate data were input into WAM model. The results showed that the monthly variability of significant wave height in the Northern Hemisphere is greater than in the Southern Hemisphere. Meanwhile, most of the equatorial regions are in calm condition all year.
Projection of Global Wave Climate Change toward the End of the Twenty-First Century
Journal of Climate, 2013
Wind-generated waves at the sea surface are of outstanding importance for both their practical relevance in many aspects, such as coastal erosion, protection, or safety of navigation, and for their scientific relevance in modifying fluxes at the air–sea interface. So far, long-term changes in ocean wave climate have been studied mostly from a regional perspective with global dynamical studies emerging only recently. Here a global wave climate study is presented, in which a global wave model [Wave Ocean Model (WAM)] is driven by atmospheric forcing from a global climate model (ECHAM5) for present-day and potential future climate conditions represented by the Intergovernmental Panel for Climate Change (IPCC) A1B emission scenario. It is found that changes in mean and extreme wave climate toward the end of the twenty-first century are small to moderate, with the largest signals being a poleward shift in the annual mean and extreme significant wave heights in the midlatitudes of both he...
Study on the wave climate variation to the renewable wave energy assessment
Renewable Energy, 2011
To reduce the dependence on fossil fuel and imported energy resources, Taiwan has ever-increasing needs of renewable energy. With the rapid development of the technologies of wave energy converter, the wave energy source will be able to meet parts the demand. The Energy Research Laboratories of the Industrial Technology Research Institute, Taiwan (2005), based on the statistic of one-year wave data, stated that the mean wave energy at the northeast coast of Taiwan reaches 11.56 kW/m, giving it the potential of wave power utilization. However, one of the major obstacles with the wave energy utilization is lack of long-term ocean wave measurements. The long-term variations in wave parameters impose changes in wave energy converter outputs. Lack of long-term data makes it difficult to assess the cost-benefit of wave energy conversion projects for the policy and decision makers. The present study aims to quantitatively evaluate the wave climate variations of the northwestern Pacific and the Taiwan Waters based on long-term wave data base. Wave observations around Taiwan have been performed since 1998, thus, earlier data of wave climate are not available. This study reconstructs the wave data of the northwest Pacific over the past three decades based on the SWAN numerical wave model that driven by NECP global reanalysis wind fields. The simulation results are compared and validated with measured data. The results show that the long-term wave climate variations around Taiwan consist of oscillations of three different periods, i.e. the seasonal, inter-annual and decade oscillations. The seasonal oscillation has significant amplitude that leads the wave energy one order magnitude greater in winter than in summer. In addition to seasonal changes, the wave energy features inter-annual variations, which are highly related to the El Nino and La Nina phenomena. In the La Nina years, the annual averaged wave energy could be double than in El Nino years. Finally, this study adopted the Man-Kendall Non-Parametric Test and the Hilbert Huang EMD method to analyze the longterm wave variation trends. The results showed that the wave height experienced climbing trends during 1976e1985 and 1997e2006, and a descending trend during 1985e1997. The reasons for wave climate oscillations in the decadal variation should be further investigation.
Ocean Engineering, 2013
This study analyzes future changes in average upper ocean physics such as sea level rise, sea surface winds and ocean wave heights by using a climate data set combining IPCC (2007) results and the latest high-resolution atmospheric general circulation model results from the Meteorological Research Institute, Japan. Ocean wave height H s is statistically projected by using multi-model ensemble method based on an empirical formula as a function of sea surface winds. The ensemble means and the standard deviations of upper ocean physics, which can be used in coastal and ocean engineering, are projected for the period between 2000 and 2100. The magnitude of the ratio of future changes in H s to the value in the present climate is at most 7 15%, which exceeds the projected changes in sea surface pressure and surface wind speed, U 10 . A large uncertainty in the projected H s can be observed around the Equator and in the Antarctic Ocean. The synoptic scale of atmospheric pressure distribution is found to be important for estimating and understanding the future changes in sea level rise, U 10 and H s .
Projection of global wave climate change towards the end of the twenty-first century
J. Climate, 2013
Wind generated waves at the sea surface are of outstanding importance for both their practical relevance in many aspects, such as coastal erosion, protection, or safety of navigation, and for their scientific relevance in modifying fluxes at the air-sea interface. So far long-term changes in ocean wave climate have been studied mostly from a regional perspective with global dynamical studies emerging only recently. Here a global wave climate study is presented, in which a global wave model (WAM) is driven by atmospheric forcing from a global climate model (ECHAM5) for present day and potential future climate conditions represented by the IPCC (Intergovernmental Panel for Climate Change) A1B emission scenario. It is found that changes in mean and extreme wave climate towards the end of the twenty-first century are small to moderate, with the largest signals being a poleward shift in the annual mean and extreme significant wave heights in the mid-latitudes of both hemispheres, more pronounced in the Southern Hemisphere, and most likely associated with a corresponding shift in mid-latitude storm tracks. These changes are broadly consistent with results from the few studies available so far. The projected changes in the mean wave periods, associated with the changes in the wave climate in the mid to high latitudes, are also shown, revealing a moderate increase in the equatorial eastern side of the ocean basins. This study presents a step forward towards a larger ensemble of global wave climate projections required to better assess robustness and uncertainty of potential future wave climate change.