共查询到20条相似文献，搜索用时 562 毫秒
1.
D.C. Cuchiara E.H. Fernandes J.C. Strauch J.C. Winterwerp L.J. Calliari 《Continental Shelf Research》2009
The main objective of this study is the characterization of the wave climate in the Southern Brazilian Shelf (SBS) based on a thorough review of existing field data and on numerical modeling experiments. A quantitative knowledge about the wave climate of this area is important to understand the mechanisms driving episodic mud bank attachments to the sandy shore, and the interaction of these banks with the flow and waves. The statistical analysis of existent data on the wave climate throughout the SBS indicates that the predominant wave directions are 100° and 160° (E–SE), with wave heights varying between 1 and 1.50 m. The wave period varies between 6 and 14 s, with predominance of mean wave period of 8 s (sea conditions) and 12 s (swell conditions). The spectral wave model SWAN version 40.41 [Booij, N., Haagsma, I.J.G., Holthuijsen, L.H., Kieftenburg, A.T.M.M., Ris, R.C., van der Westhuysen, A.J., Zijlema, M., 2004. SWAN Cycle III Version 40.41 Users Manual, Delft University of Technology, Delft, The Netherlands, p. 118, http://fluidmechanics.tudelft.nl/swan/index.htm] is used to simulate the wave climate for the region. Special attention is given to Cassino Beach, describing the wave climate observed during the Cassino Experiment, carried out in 2005. The verification of the standard SWAN model was carried out based on the comparison between numerical modeling results and available data of significant wave height, peak period, mean wave direction and energy density for the period relative to February of 1998. Results showed satisfactory model predictions of significant wave height and reasonably accurate predictions of peak spectral wave period and direction. The model performance is also considered satisfactory in the representation of the wave climate of the region when the wave spectrum has only one spectral peak, but presents limitations for bimodal wave spectrum. When two spectral peaks are observed, the SWAN model agrees with the spectral level observed in the low frequency, but underestimates the spectral level in the high-frequency band. When considering the presence of mud deposits in the area, model results predict that although the presence of mud attenuates most of the wave energy on the low frequency peak, it has a smaller effect in attenuating the wave energy on the high frequency peak. 相似文献
2.
Anna Zacharioudaki Shunqi Pan Dave Simmonds Vanesa Magar Dominic E. Reeve 《Ocean Dynamics》2011,61(6):807-827
In this paper, we investigate changes in the wave climate of the west-European shelf seas under global warming scenarios.
In particular, climate change wind fields corresponding to the present (control) time-slice 1961–2000 and the future (scenario)
time-slice 2061–2100 are used to drive a wave generation model to produce equivalent control and scenario wave climate. Yearly
and seasonal statistics of the scenario wave climates are compared individually to the corresponding control wave climate
to identify relative changes of statistical significance between present and future extreme and prevailing wave heights. Using
global, regional and linked global–regional wind forcing over a set of nested computational domains, this paper further demonstrates
the sensitivity of the results to the resolution and coverage of the forcing. It suggests that the use of combined forcing
from linked global and regional climate models of typical resolution and coverage is a good option for the investigation of
relative wave changes in the region of interest of this study. Coarse resolution global forcing alone leads to very similar
results over regions that are highly exposed to the Atlantic Ocean. In contrast, fine resolution regional forcing alone is
shown to be insufficient for exploring wave climate changes over the western European waters because of its limited coverage.
Results obtained with the combined global–regional wind forcing showed some consistency between scenarios. In general, it
was shown that mean and extreme wave heights will increase in the future only in winter and only in the southwest of UK and
west of France, north of about 44–45° N. Otherwise, wave heights are projected to decrease, especially in summer. Nevertheless,
this decrease is dominated by local wind waves whilst swell is found to increase. Only in spring do both swell and local wind
waves decrease in average height. 相似文献
3.
Climate and variability bias adjustment of climate model-derived winds for a southeast Australian dynamical wave model 总被引：1，自引：1，他引：0
Climate models are increasingly being used to force dynamical wind wave models in order to assess the potential climate change-driven
variations in wave climate. In this study, an ensemble of wave model simulations have been used to assess the ability of climate
model winds to reproduce the present-day (1981–2000) mean wave climate and its seasonal variability for the southeast coast
of Australia. Surface wind forcing was obtained from three dynamically downscaled Coupled Model Intercomparison Project (CMIP-3)
global climate model (GCM) simulations (CSIRO Mk3.5, GFDLcm2.0 and GFDLcm2.1). The downscaling was performed using CSIRO’s
cubic conformal atmospheric model (CCAM) over the Australian region at approximately 60-km resolution. The wind climates derived
from the CCAM downscaled GCMs were assessed against observations (QuikSCAT and NCEP Re-analysis 2 (NRA-2) reanalyses) over
the 1981–2000 period and were found to exhibit both bias in mean wind conditions (climate bias) as well as bias in the variance
of wind conditions (variability bias). Comparison of the modelled wave climate with over 20 years of wave data from six wave
buoys in the study area indicates that direct forcing of the wave models with uncorrected CCAM winds result in suboptimal
wave hindcast. CCAM winds were subsequently adjusted for climate and variability bias using a bivariate quantile adjustment
which corrects both directional wind components to align in distribution to the NRA-2 winds. Forcing of the wave models with
bias-adjusted winds leads to a significant improvement of the hindcast mean annual wave climate and its seasonal variability.
However, bias adjustment of the CCAM winds does not improve the ability of the model to reproduce the storm wave climate.
This is likely due to a combination of storm systems tracking too quickly through the wave generation zone and the performance
of the NRA-2 winds used as a benchmark in this study. 相似文献
4.
Recent shifts in coastline change and shoreline stabilization linked to storm climate change 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Jennifer M. Johnson Laura J. Moore Kenneth Ells A. Brad Murray Peter N. Adams Richard A. MacKenzie III John M. Jaeger 《地球表面变化过程与地形》2015,40(5):569-585
Since cuspate coastlines are especially sensitive to changes in wave climate, they serve as potential indicators of initial responses to changing wave conditions. Previous work demonstrates that Cape Hatteras and Cape Lookout, North Carolina, which are largely unaffected by shoreline stabilization efforts, have become increasingly asymmetric over the past 30 years, consistent with model predictions for coastline response to increases in Atlantic Ocean summer wave heights and resulting changes in the distribution of wave‐approach angles. Historic and recent shoreline change observations for Cape Fear, North Carolina, and model simulations of coastline response to an increasingly asymmetric wave climate in the presence of beach nourishment, produce comparable differences in shoreline change rates in response to changes in wave climate. Results suggest that the effect of beach nourishment is to compensate for – and therefore to mask – natural responses to wave climate change that might otherwise be discernible in patterns of shoreline change alone. Therefore, this case study suggests that the effects of wave climate change on human‐modified coastlines may be detectable in the spatial and temporal patterns of shoreline stabilization activities. Similar analyses of cuspate features in areas where the change in wave climate is less pronounced (i.e. Fishing Point, Maryland/Virginia) and where local geology appears to exert control on coastline shape (i.e. Cape Canaveral, Florida), suggest that changes in shoreline configuration that may be arising from shifting wave climate are currently limited to sandy wave‐dominated coastlines where the change in wave climate has been most pronounced. However, if hurricane‐generated wave heights continue to increase, large‐scale shifts in patterns of erosion and accretion will likely extend beyond sensitive cuspate features as the larger‐scale coastline shape comes into equilibrium with changing wave conditions. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
5.
Renske C. de Winter Andreas Sterl Johannes W. de Vries Susanne L. Weber Gerben Ruessink 《Ocean Dynamics》2012,62(8):1139-1152
Coastal safety may be influenced by climate change, as changes in wave conditions (height, period, direction) may increase the vulnerability of dunes and other coastal defences. Dune erosion depends on mean water level, storm surge height and wave conditions. In this paper, we investigate the change in wave conditions in the North Sea in a changing climate. Until now, the effect of climate change on annual maximum wave conditions has been investigated, while events with higher return periods are actually most damaging for the coast (e.g. severe dune erosion). Here, we use the 17-member Ensemble SimulationS of Extreme weather under Non-linear Climate changeE (ESSENCE) change of climate change simulations, to analyse A1b-induced changes in the mean wave climate, the annual maxima and wave conditions with return periods of up to 1:10,000?years in front of the Dutch coast. The mean wave climate is not projected to differ between 1961–1990 and 2071–2100, with both wave height (H s) and wave period (T m) remaining unaltered. In the annual maximum conditions, a decrease is projected; especially, the annual T m maximum decreases significantly by 0.3 to 0.6?s over the whole study area. Furthermore, we find that the direction of the annual maximum wave conditions shifts from north and north-west to west and south-west for both H s and T m. This is induced by a similar shift in the direction of the extreme wind speeds. Despite the decrease in annual maximum conditions, the return H s and T m are not projected to change significantly as a result of climate change in front of the Dutch coast for the period 2071–2100 relative to 1961–1990. 相似文献
6.
Ocean Dynamics - A numerical wave model was used to determine the wave climate in the southern Baltic Sea. The basic data derived from wave hindcasts were evaluated statistically. Climate graphs... 相似文献
7.
Excessive usage of fossil fuels and high emission of greenhouse gases have increased the earth’s temperature and consequently have led to changes in wind and wave regimes. The main effects of climate change on oceans are warming of the ocean water, melting of ice, acidification of ocean water, and change in the ocean currents. The main effects of climate change on coastal regions are change in the coast hydrodynamics, sea level rise, change in wave height, coastal erosion, coastal structure damage, food shortage, and storms. Due to the importance of waves in the coastal zone and its effect on erosion and sedimentation, it is necessary to study wave changes. In this study, the effect of climate change on wave specifications was evaluated in the southern coast of the Caspian Sea in Noshahr Port. To simulate wave parameters, the third generation spectral Simulating WAves Nearshore (SWAN) model was used. Wave modeling was carried out using the SWAN numerical model for two 30-yearly periods, including the control period (1984 to 2014) and the future period (2051 to 2080). For wave modeling in the control period, the European Center for Average Weather Forecast wind field was used, and for the future period, a downscaled wind field from Coordinated Regional Downscaling Experiment projection, which was sponsored by World Climate Research Programme, based on the most recent emission scenarios RCP2.6, RCP4.5, and RCP8.5, was used. The model results were calibrated and verified with buoy-recorded data. The effect of the climate change on the wave parameters was evaluated by studying the differences between the patterns in three scenarios and the control period. Results showed that the 30-year maximum significant wave height will increase because of climate change, and the wave direction will not change. In addition, the intensity of storms will increase in the future.
相似文献8.
Climate change impact on extreme wave conditions in the North Sea: an ensemble study 总被引：1，自引：1，他引：0
An analysis of today’s mean and extreme wave conditions in the North Sea and their possible future changes due to anthropogenic climate change are presented. The sea state was simulated for the 30-year period 2071–2100 using the wave model WAM and an ensemble of wind field data sets for four climate change realizations as driving data. The wind field data sets are based on simulation outputs from two global circulation models (GCMs: HadAM3H and ECHAM4/OPYC3) for two emission scenarios (A2 and B2, Intergovernmental Panel on Climate Change, Special Report on Emission Scenarios). They were regionalized by the Swedish Meteorological and Hydrological Institute using the regional climate model RCAO. The effects of the climate realizations on the sea state statistics were assessed by analyzing the differences between the patterns in the four CGM/emission scenario combinations and those in two control simulations representing reference wave climate conditions for the 30-year period 1961–1990. The analysis of the four emission scenario/GCM combinations has shown that the future long-term 99 percentile wind speed and significant wave height increase by up to 7% and 18%, respectively, in the North Sea, except for significant wave height off the English coast and to the north in the HadAM3H-driven simulation. The climate change response in the ECHAM4/OPYC3-forced experiments is generally larger than in the HadAM3H-driven simulations. The differences in future significant wave height between the different combinations are in the same order of magnitude as those between the control runs for the two GCMs. Nevertheless, there is agreement among the four combinations that extreme wave heights may increase in large parts in the southern and eastern North Sea by about 0.25 to 0.35 m (5–8% of present values) towards the end of the twenty first century in case of global warming. All combinations also show an increase in future frequency of severe sea state. 相似文献
9.
Alphonse Nahon Déborah Idier Nadia Sénéchal Hugues Féniès Cyril Mallet Julie Mugica 《地球表面变化过程与地形》2019,44(11):2112-2125
In coastal areas, sea level rise (SLR) and changing wave climates are expected to be the main oceanic drivers of shoreline adjustments. These drivers have been shown to vary on a wide spectrum of spatial and temporal scales. Nonetheless, a general rule about how this variability impacts global shorelines remains to be articulated. Here, we discuss the impacts of wave climate changes and SLR on the evolution of a barrier spit–inlet system over the last 250 years. The distal end of the Cap Ferret barrier spit, SW France, has undergone large-scale oscillations that were well correlated with variations of the decadal average of the winter North Atlantic Oscillation (NAO) index. The local wave climate hindcast supports that increased alongshore wave energy fluxes associated with the positive phase of the NAO were responsible for the updrift retreat of the spit. By opposition, the spit has elongated downdrift when waves were less energetic and more shore normal, as during the negative phase of the NAO. In addition, lower rates of SLR appeared to be necessary for the spit to develop, as higher rates of SLR very likely forced the adjacent inlet to enlarge, at the expense of the spit. These results should help to predict and detect coastal adjustments driven by climate change and by climate variability. © 2019 John Wiley & Sons, Ltd. 相似文献
10.
The multi-decadal wave conditions in the North Sea can be influenced by anthropogenic climate change. That may lead to the intensification of wave extremes in the future and consequently increase risks for the coastal areas as well as for on- and offshore human activities. Potential changes caused by alteration of atmospheric patterns are investigated. Four transient climate projections (1961–2100), reflecting two IPCC emission scenarios (A1B and B1) and two different initial states, are used to simulate the wave scenarios. The potential wind-induced changes in waves are studied by comparing future statistics (2001–2100) with the corresponding reference conditions (1961–2000). Generally, there is a small increase in future 99th percentile significant wave height for most eastern parts of the North Sea towards the end of the twenty-first century. This small increase is superimposed by a strong variability of the annual extremes on time scales of decades. Opposite to the differences in wave height, the change in wave direction to more waves propagating east shows less decadal variability and is more uniform among all realizations. Nevertheless, temporal and spatial differences of the wave height in the four climate projections point to the uncertainties in the climate change signals. 相似文献
11.
Inter-annual variability and longer-term changes in the wave climate of Western Australia between 1970 and 2009 总被引：2，自引：1，他引：1
Quantifying the long-term variability in wave conditions incident on a coastline is critical for predicting its resilience
to future changes in the wave climate. In this study, a 40-year wave hindcast of the southern Indian Ocean has been created
to assess the inter-annual variability and longer-term changes in the wave climate around Western Australia (WA) between 1970
and 2009. The model was validated against measurements from five wave buoys located along the WA coast. Changes in the mean
annual significant wave height, 90th percentile wave height, peak period and mean wave direction were assessed, and the tracks
of all wave events generating wave heights above 7 m were digitised and analysed for significant changes. Results show strong
annual and inter-annual variability in the mean significant wave height, the 90th percentile wave height and the number of
large events (wave height > 7 m) that impact the WA coastline. A significant positive trend in annual mean wave height was
found in the southwest region of WA over the 40-year simulation. This appears to be due to an increase in intensity of the
storm belt in the Southern Ocean which is associated with an increasing positive polarity in the Southern Annular Mode. However,
no significant trends were found in the 90th percentile wave height or the number of large wave events impacting Western Australia.
Although the number of large wave events in the southern Indian Ocean have increased, their potential to impact the coastal
regions of Western Australia are reduced due to storm tracks being located further south, therefore balancing the number of
large wave events reaching the WA coast. 相似文献
12.
Christopher J. Daly Karin R. Bryan Mauricio R. Gonzalez Antonio H. F. Klein Christian Winter 《Ocean Dynamics》2014,64(6):863-877
In order to decrease the simulation time of morphodynamic models, often-complex wave climates are reduced to a few representative wave conditions (RWC). When applied to embayed beaches, a test of whether a reduced wave climate is representative or not is to see whether it can recreate the observed equilibrium (long-term averaged) bathymetry of the bay. In this study, the wave climate experienced at Milagro Beach, Tarragona, Spain was discretized into ‘average’ and ‘extreme’ RWCs. Process-based morphodynamic simulations were sequenced and merged based on ‘persistent’ and ‘transient’ forcing conditions, the results of which were used to estimate the equilibrium bathymetry of the bay. Results show that the effect of extreme wave events appeared to have less influence on the equilibrium of the bay compared to average conditions of longer overall duration. Additionally, the persistent seasonal variation of the wave climate produces pronounced beach rotation and tends to accumulate sediment at the extremities of the beach, rather than in the central sections. It is, therefore, important to account for directional variability and persistence in the selection and sequencing of representative wave conditions as is it essential for accurately balancing the effects beach rotation events. 相似文献
13.
Paula Camus Fernando J. Méndez Inigo J. Losada Melisa Menéndez Antonio Espejo Jorge Pérez Ana Rueda Yanira Guanche 《Ocean Dynamics》2014,64(7):1025-1038
In this study, a method to obtain local wave predictor indices that take into account the wave generation process is described and applied to several locations. The method is based on a statistical model that relates significant wave height with an atmospheric predictor, defined by sea level pressure fields. The predictor is composed of a local and a regional part, representing the sea and the swell wave components, respectively. The spatial domain of the predictor is determined using the Evaluation of Source and Travel-time of wave Energy reaching a Local Area (ESTELA) method. The regional component of the predictor includes the recent historical atmospheric conditions responsible for the swell wave component at the target point. The regional predictor component has a historical temporal coverage (n-days) different to the local predictor component (daily coverage). Principal component analysis is applied to the daily predictor in order to detect the dominant variability patterns and their temporal coefficients. Multivariate regression model, fitted at daily scale for different n-days of the regional predictor, determines the optimum historical coverage. The monthly wave predictor indices are selected applying a regression model using the monthly values of the principal components of the daily predictor, with the optimum temporal coverage for the regional predictor. The daily predictor can be used in wave climate projections, while the monthly predictor can help to understand wave climate variability or long-term coastal morphodynamic anomalies. 相似文献
14.
The morphologic changes in estuaries and coastal lagoons are very complex and constitute a challenging task in coastal research.
The bathymetric changes result from the combined action of tides, waves, rivers discharge and wind stress in the area of interest.
Additionally, an accurate knowledge of the sediment transport is essential to achieve a good morphological characterization.
This work establishes the influence of the wave climate on the morphodynamics of the Ria de Aveiro lagoon inlet by analysing the numerical results of the morphodynamic modelling system MORSYS2D. The numerical simulations
considered a realistic coupled forcing of tidal currents and waves. The computed sediment fluxes and bathymetric changes are
analysed and compared with the erosion and accretion trends obtained from the numerical simulations forced only by tidal currents,
in order to establish the wave climate influence. The final bathymetry and the corresponding changes are compared with bathymetric
data collected through surveys. It is concluded that: (a) the morphodynamics of the study area is dominated by the wave regime
in the lagoon inlet and nearshore areas, while in the inner areas is tidally dominated; and (b) the inclusion of the wave
regime forcing constitutes an improvement in order to accurately reproduce the local morphodynamics. 相似文献
15.
Effects of non-rigid muddy bed on the wave climate at the Hendijan coast along the northwestern part of the Persian Gulf have been examined through field measurements and numerical wave transformation modeling. The field survey included measurements of wave characteristics at an offshore and a nearshore station, and mud sampling to obtain the thickness of the fluid mud layer and its rheological properties. Comparisons of wave spectra at the two stations show energy dissipation along the wave trajectory with higher dissipation in the wave period band around 6?s, because depending on the site a given frequency band tends to be more effective in wave–mud interaction. Dissipation induced by the non-rigid bed is introduced into the REF/DIF wave transformation model through the application of viscoelastic constitutive equations for fluid mud. Numerical outputs of the nearshore wave height, for which the viscoelastic parameters included in the model were obtained independently from oscillatory frequency-sweep tests, are found to be comparable with measured values at the nearshore station. This implies that the model is useful for estimating the design wave conditions in the study area. 相似文献
16.
Ocean Dynamics - A detailed analysis of how the wave climate gradually varies from the Atlantic coast to the Rio de la Plata (RDP) estuary coast of Uruguay is undertaken, exploiting a recently... 相似文献
17.
Several downscaling techniques, comprising fully dynamical and statistical–dynamical methods applied to near-shore local wave climate, are tested and assessed in terms of wave statistics with respect to the added value that can be achieved compared to larger scale data. The techniques are applied for the example of Helgoland, a small island in the German Bight. It was found that an improved representation could generally be obtained from all downscaling techniques by comparing the near-shore wave climate. Based on a balance between the required computer resources and the improvements achieved, it is suggested, to this end, that a dynamical–statistical approach based on high-resolution coastal wave modeling and linear regression provides the optimal choice. 相似文献
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