scholarly journals ENSEMBLE WAVE CLIMATE PROJECTIONS BASED ON CMIP5 MODELS

2020 ◽  
pp. 23
Author(s):  
Nobuhito Mori ◽  
Joao Morim ◽  
Mark Hemer ◽  
Xiaolan L. Wang ◽  
COWCLIP Project
Keyword(s):  
Wave Climate ◽  
Global Scale ◽  
Coastal Hazards ◽  
Cmip5 Models ◽  
Climate Projections ◽  
Storm Frequency ◽  
Dominant Process ◽  
Wave Conditions ◽  
Ocean Wave Climate

A warming climate has the potential to not only raise sea level but also exacerbate coastal hazards due to changes in storm frequency and intensity. Along open coasts where wave energy is often the dominant process dictating shoreline positions, changes in mean and extreme wave conditions are likely to alter long-term geomorphic evolution patterns. The Coordinated Ocean Wave Climate Project (COWCLIP) is to provide infrastructure to support a systematic, community-based framework that allows for validation and inter-comparison of wave projections. Here, the primary aims are to 1) present quantitative evaluations of projected global scale wave conditions and 2) to present the framework and preliminary results of regional wave modeling that will provide projections of nearshore wave conditions for use in long-term geomorphic change analyzes.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/Y6BEHq5wZXw

scholarly journals Climate-induced variability in South Atlantic wave direction over the past three millennia

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
A. P. Silva ◽  
A. H. F. Klein ◽  
A. F. H. Fetter-Filho ◽  
C. J. Hein ◽  
F. J. Méndez ◽  
...  
Keyword(s):  
Global Climate ◽  
Southern Annular Mode ◽  
Wave Climate ◽  
Wave Generation ◽  
South Atlantic ◽  
Wave Direction ◽  
Global Climate Changes ◽  
Ocean Wave Climate ◽  
Forcing Mechanisms

Abstract Through alteration of wave-generating atmospheric systems, global climate changes play a fundamental role in regional wave climate. However, long-term wave-climate cycles and their associated forcing mechanisms remain poorly constrained, in part due to a relative dearth of highly resolved archives. Here we use the morphology of former shorelines preserved in beach-foredune ridges (BFR) within a protected embayment to reconstruct changes in predominant wave directions in the Subtropical South Atlantic during the last ~ 3000 years. These analyses reveal multi-centennial cycles of oscillation in predominant wave direction in accordance with stronger (weaker) South Atlantic mid- to high-latitudes mean sea-level pressure gradient and zonal westerly winds, favouring wave generation zones in higher (lower) latitudes and consequent southerly (easterly) wave components. We identify the Southern Annular Mode as the primary climate driver responsible for these changes. Long-term variations in interhemispheric surface temperature anomalies coexist with oscillations in wave direction, which indicates the influence of temperature-driven atmospheric teleconnections on wave-generation cycles. These results provide a novel geomorphic proxy for paleoenvironmental reconstructions and present new insights into the role of global multi-decadal to multi-centennial climate variability in controlling coastal-ocean wave climate.

scholarly journals A Multimodal Wave Spectrum–Based Approach for Statistical Downscaling of Local Wave Climate

2017 ◽  
Vol 47 (2) ◽  
pp. 375-386 ◽  
Author(s):  
C. A. Hegermiller ◽  
J. A. A. Antolinez ◽  
A. Rueda ◽  
P. Camus ◽  
J. Perez ◽  
...  
Keyword(s):  
Statistical Downscaling ◽  
Wave Spectrum ◽  
Wave Climate ◽  
Ocean Basin ◽  
Coastal Hazards ◽  
Wave Spectra ◽  
Bulk Wave ◽  
Wave Parameters ◽  
Local Wave ◽  
Wave Conditions

AbstractCharacterization of wave climate by bulk wave parameters is insufficient for many coastal studies, including those focused on assessing coastal hazards and long-term wave climate influences on coastal evolution. This issue is particularly relevant for studies using statistical downscaling of atmospheric fields to local wave conditions, which are often multimodal in large ocean basins (e.g., Pacific Ocean). Swell may be generated in vastly different wave generation regions, yielding complex wave spectra that are inadequately represented by a single set of bulk wave parameters. Furthermore, the relationship between atmospheric systems and local wave conditions is complicated by variations in arrival time of wave groups from different parts of the basin. Here, this study addresses these two challenges by improving upon the spatiotemporal definition of the atmospheric predictor used in the statistical downscaling of local wave climate. The improved methodology separates the local wave spectrum into “wave families,” defined by spectral peaks and discrete generation regions, and relates atmospheric conditions in distant regions of the ocean basin to local wave conditions by incorporating travel times computed from effective energy flux across the ocean basin. When applied to locations with multimodal wave spectra, including Southern California and Trujillo, Peru, the new methodology improves the ability of the statistical model to project significant wave height, peak period, and direction for each wave family, retaining more information from the full wave spectrum. This work is the base of statistical downscaling by weather types, which has recently been applied to coastal flooding and morphodynamic applications.

MODELING PROPOSAL: Coordinating Global Ocean Wave Climate Projections

2010 ◽  
Vol 91 (4) ◽  
pp. 451-454 ◽  
Author(s):  
M. A. Hemer ◽  
X. L. Wang ◽  
J. A. Church ◽  
V. R. Swail
Keyword(s):  
Wave Climate ◽  
Ocean Wave ◽  
Global Ocean ◽  
Climate Projections ◽  
Ocean Wave Climate

scholarly journals Interannual Response of Reef Islands to Climate-Driven Variations in Water Level and Wave Climate

2020 ◽  
Vol 12 (24) ◽  
pp. 4089
Author(s):  
Michael V. W. Cuttler ◽  
Kilian Vos ◽  
Paul Branson ◽  
Jeff E. Hansen ◽  
Michael O’Leary ◽  
...  
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Southern Oscillation ◽  
Wave Climate ◽  
Water Levels ◽  
Short Term ◽  
Island Evolution ◽  
Reef Islands ◽  
Wave Conditions

Coral reef islands are among the most vulnerable landforms to climate change. However, our understanding of their morphodynamics at intermediate (seasonal to interannual) timescales remains poor, limiting our ability to forecast how they will evolve in the future. Here, we applied a semi-automated shoreline detection technique (CoastSat.islands) to 20 years of publicly available satellite imagery to investigate the evolution of a group of reef islands located in the eastern Indian Ocean. At interannual timescales, island changes were characterized by the cyclical re-organization of island shorelines in response to the variability in water levels and wave conditions. Interannual variability in forcing parameters was driven by El Niño Southern Oscillation (ENSO) cycles, causing prolonged changes to water levels and wave conditions that established new equilibrium island morphologies. Our results present a new opportunity to measure intermediate temporal scale changes in island morphology that can complement existing short-term (weekly to seasonal) and long-term (decadal) understanding of reef island evolution.

scholarly journals WIND WAVE FREQUENCIES IN A TROPICAL CYCLONE REGION

1978 ◽  
Vol 1 (16) ◽  
pp. 3
Author(s):  
Rodney J. Sobay
Keyword(s):  
Tropical Cyclone ◽  
Continental Shelf ◽  
Wind Wave ◽  
Wave Climate ◽  
Extreme Value Analysis ◽  
Local Wind ◽  
Value Analysis ◽  
Coral Sea ◽  
Wave Conditions

Australia's Coral Sea coast from Bundaberg north to Cape York has a wind wave climate that is almost unique. The coastline is afforded unparalleled protection from the 1900 km Great Barrier Reef, yet it lies in a tropical cyclone region and must expect recurrent intense wind and wave conditions. The Great Barrier Reef is a continuous chain of quite separate coral reef clusters located near the edge of the continental shelf. The separate reefs are often exposed at low tide, the inner fringe of the clusters ranges from 10 km offshore north of Cairns to 200 km offshore south of Rockhampton and the outer fringe is typically some 50 km further offshore, beyond which the ocean bed drops rapidly away. Incident wave energy from the Coral Sea is invariably dissipated on the outer edge of the Reef and wave conditions on the continental shelf can reasonably be considered due to local wind conditions. The Reef imposes an effective fetch limitations on wave generation over the continental shelf and there is, as a consequence, a moderately rapid response of wave conditions to changes in local wind conditions. A pronounced diurnal variation in the wind climate is reflected also in the wave climate and the stability of the region's tropical climate leads to frequent calm to slight sea conditions. This stability however is occasionally exploded by the generation and passage of a tropical cyclone in mid to late summer. Large waves can be generated by the intense winds of the tropical cyclone (hurricane or typhoon), often an order of magnitude greater than those in response to non-cyclonic events. The rational design of coastal structures and the rational pursuit of coastal zone management requires appropriate estimates of the frequency of occurrence of waves of various heights. Ideally such information is obtained from an extreme value analysis of long term wave records at the particular site in question. Permanent wave recording programs unfortunately have only become common practice in the present decade and wave records, if they exist at all for a particular site, are rarely long enough to allow a satisfactory extreme value analysis. It is clear, in the Australian context at least, that historical wave data alone is not yet sufficient to derive satisfactory estimates of long term wave frequencies. The alternative is system modelling. Wind is a major meteorological variable and its long term recording has been a standard meteorological practice now for over half a century.

scholarly journals LONG-TERM, ENSEMBLE, DATA-ASSIMILATED SHORELINE CHANGE MODELING

2020 ◽  
pp. 25
Author(s):  
Sean Vitousek ◽  
Laura Cagigal ◽  
Jennifer Montano ◽  
Ana Rueda ◽  
Fernando Mendez ◽  
...  
Keyword(s):  
Time Series ◽  
Climate Model ◽  
Global Climate Model ◽  
Shoreline Change ◽  
Wave Climate ◽  
Coastal Change ◽  
Atmospheric Conditions ◽  
Single Realization ◽  
Wave Conditions

We present an ensemble Kalman filter shoreline change model to predict long-term coastal evolution due to waves, sea-level rise, and other natural and anthropogenic processes responsible for sediment transport. The model utilizes ensemble simulations to improve both reliability (via data assimilation) and uncertainty quantification. Coastal change projections exhibit significant differences when simulated with and without ensemble wave conditions. Many long-term coastal change projections rely on a single realization of the future wave climate, often derived from atmospheric conditions simulated by a global climate model. Yet, the single realization approach does not account for the stochastic nature of future wave conditions across a variety of temporal scales (e.g., daily, weekly, seasonally, and interannually). Here, by applying ensemble time series of wave forcing conditions, we demonstrate a sizable increase in model uncertainty compared with the unrealistic case of model projections based on a single realization (e.g., a single time series) of wave forcing.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/V-VwC-cIiQ0

scholarly journals A global ensemble of ocean wave climate projections from CMIP5-driven models

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Joao Morim ◽  
Claire Trenham ◽  
Mark Hemer ◽  
Xiaolan L. Wang ◽  
Nobuhito Mori ◽  
...  
Keyword(s):  
Wave Climate ◽  
Ocean Wave ◽  
Climate Projections ◽  
Ocean Wave Climate

scholarly journals Future Projection of Ocean Wave Climate: Analysis of SST Impacts on Wave Climate Changes in the Western North Pacific

2015 ◽  
Vol 28 (8) ◽  
pp. 3171-3190 ◽  
Author(s):  
Tomoya Shimura ◽  
Nobuhito Mori ◽  
Hajime Mase
Keyword(s):  
Wave Height ◽  
North Pacific ◽  
Western North Pacific ◽  
Climate Changes ◽  
Ocean Surface ◽  
Wave Climate ◽  
Ocean Wave ◽  
Climate Projections ◽  
The Future ◽  
Ocean Wave Climate

Abstract Changes in ocean surface waves elicit a variety of impacts on coastal environments. To assess the future changes in the ocean surface wave climate, several future projections of global wave climate have been simulated in previous studies. However, previously there has been little discussion about the causes behind changes in the future wave climate and the differences between projections. The objective of this study is to estimate the future changes in mean wave climate and the sensitivity of the wave climate to sea surface temperature (SST) conditions in an effort to understand the mechanism behind the wave climate changes by specifically looking at spatial SST variation. A series of wave climate projections forced by surface winds from the MRI-AGCM3.2 were conducted based on SST ensemble experiments. The results yield future changes in annual mean wave height that are within about ±0.3 m. The future changes in summertime wave height in the western North Pacific (WNP), which are influenced by tropical cyclone changes, are highly sensitive to SST conditions. To generalize the result, the wave climate change and SST relation found by this study was compared with multimodel wave ensemble products from the Coordinated Ocean Wave Climate Project (COWCLIP). The spatial variation of SST in the tropical Pacific Ocean is a major factor in the wave climate changes for the WNP during summer.

Time Series Analysis of Significant Wave Height Data for Identification of Trends in the Ocean Wave Climate

2013 ◽  
Author(s):  
Erik Vanem ◽  
Sam-Erik Walker
Keyword(s):  
Time Series ◽  
Wave Height ◽  
Significant Wave Height ◽  
Wave Climate ◽  
Ocean Wave ◽  
Significant Wave ◽  
Long Time ◽  
Long Term Trends ◽  
Ocean Wave Climate

Reliable return period estimates of sea state parameters such as the significant wave height is of great importance in marine structural design and ocean engineering. Hence, time series of significant wave height have been extensively studied in recent years. However, with the possibility of an ongoing change in the global climate, this might influence the ocean wave climate as well and it would be of great interest to analyze long time series to see if any long-term trends can be detected. In this paper, long time series of significant wave height stemming from the ERA-40 reanalysis project, containing 6-hourly data over a period of more than 44 years are investigated with the purpose of identifying long term trends. Different time series analysis methods are employed, i.e. seasonal ARIMA, multiple linear regression, the Theil-Sen estimator and generalized additive models, and the results are discussed. These results are then compared to previous studies; in particular results are compared to a recent study where a spatio-temporal stochastic model was applied to the same data. However, in the current analysis, the spatial dimension has been reduced and spatial minima, mean and maxima have been analysed for temporal trends. Overall, increasing trends in the wave climate have been identified by most of the modelling approaches explored in the paper, although some of the trends are not statistically significant at the 95% level. Based on the results presented in this paper, it may be argued that there is evidence of a roughening trend in the recent ocean wave climate, and more detailed analyses of individual months and seasons indicate that these trends might be mostly due to trends during the winter months.

scholarly journals CLIMATE VARIABILITY INDUCED SHIFTS OF THE WAVE CLIMATE IN MEXICO

2020 ◽  
pp. 21
Author(s):  
Rodolfo Silva ◽  
Itxaso Oderiz ◽  
Thomas Mortlock ◽  
Ismael Marino-Tapia
Keyword(s):  
Sediment Transport ◽  
Southern Oscillation ◽  
Wave Climate ◽  
Global Scale ◽  
Wave Direction ◽  
Erosion Risk ◽  
Primary Driver ◽  
Important Challenge ◽  
Offshore Wave

Inter-annual variability of wave climates is important for coastal risk assessment because these fluctuations can increase or decrease seasonal erosion risk (Wahl and Plant 2015). Understanding how long-term variability affects the seasonality of sediment transport is an important challenge in risk assessments (Toimil et al. 2020). There have been many attempts to quantify long-term variability in offshore wave climate, as this is the primary driver of coastal processes on sandy coasts. However, there is very little work on how the long-term variability of wave climate influences sediment transport. One of the most important drivers of sediment transport is the mean wave direction of incoming waves (Barnard et al. 2015; Hemer, Church, and Hunter 2010; Morim et al. 2019), although it is still not fully understood. An important contribution in this regard is the work of (Barnard et al. 2015), who found that El Nio Southern Oscillation (ENSO) dominates coastal vulnerability in the Pacific Ocean. On the other hand, several works at global scale (Godoi and Torres Junior 2020; Reguero, Losada, and Mendez 2019; Stopa and Cheung 2014) have found that ENSO is the climatic driver that most affects the interannual variability of the wave climate. However, understanding how ENSO impacts wave direction is still lacking.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/_M5Mxm7PnQg

Sign in / Sign up

Export Citation Format

Share Document