scholarly journals EXTREME WAVE PARAMETERS BASED ON CONTINENTAL SHELF STORM WAVE RECORDS

1976 ◽  
Vol 1 (15) ◽  
pp. 9 ◽  
Author(s):  
R.E. Haring ◽  
A.R. Osborne ◽  
L.P. Spencer
Keyword(s):  
Continental Shelf ◽  
Rayleigh Distribution ◽  
Probability Level ◽  
Extreme Wave ◽  
Spectral Parameters ◽  
Wave Parameters ◽  
Individual Wave ◽  
Storm Wave ◽  
Surface Deviation ◽  
Wave Heights

Measured storm wave records from several Continental Shelf areas were used to test the adequacy of estimating formulae for individual wave parameters. In all, 376 hours of storm wave records were analyzed, and their properties nondimensionalized by fundamental spectral parameters. Results are presented for surface deviation statistics, individual wave height statistics and individual wave period statistics. The results can be used by ocean engineers to eliminate unintended bias from wave parameters selected for the design of offshore facilities. The most significant result is that measured rare wave heights in the storm wave records are on the order of 10 percent less than predicted by the Rayleigh distribution at the 1 in 1000 probability level.

scholarly journals WAVE HEIGHT DISTRIBUTION IN CONSTANT AND FINITE DEPTHS

2012 ◽  
Vol 1 (33) ◽  
pp. 15 ◽  
Author(s):  
Sofia Caires ◽  
Marcel R.A. Van Gent
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Wave Breaking ◽  
Rayleigh Distribution ◽  
Height Distribution ◽  
High Wave ◽  
Wave Height Distribution ◽  
Individual Wave ◽  
Wave Heights

Several alternatives to the Rayleigh distribution have been proposed for describing individual wave heights in regions where depth-induced wave breaking occurs. The most widely used of these is the so-called Battjes and Groenendijk distribution. This distribution has been derived and validated in a context of a shallow water foreshore waves propagating over a gently sloping shallow region towards the shore. Its validity for waves propagating in regions with shallow flat bottoms is investigated here. It is concluded that the distribution on average underestimates (outside its range of validity) high wave height measurements in shallow flat bottoms by as much as 15%.

scholarly journals Calculation of the wave parameters for sea dyke design and upgrading

2008 ◽  
Vol 30 (4) ◽  
Author(s):  
Nguyen Manh Hung ◽  
Nguyen Khac Nghia ◽  
Duong Cong Dien
Keyword(s):  
Coastal Zone ◽  
Red River Delta ◽  
Storm Activity ◽  
Technology Program ◽  
Wave Parameters ◽  
Storm Wave ◽  
Wave Heights ◽  
Wave Models ◽  
Quang Ninh ◽  
Wave Calculation

Sea dyke system is the effective mean for protecting the coastal low-lying areas from storm attack (the most dangerous storm induced phenomena are storm wave and surges). The coastal zone of Vietnam is blessed with wide variety of natural resources but at the same time, it is also a highly storm hazard-prone region. The storm number 7 (DAMREY) arrived in the East Sea from 26th to 28th of September 2005 and hit the south part of Red river delta coastal zone and caused sea dykes breaches at some stretches along the sea dyke system of the Nam Dinh province and big property damages of the local communes. In order to cope with the storm activity which is reinforced in the future by climate change, a Science Technology program on the sea dyke upgrading from Quang Ninh to Quang Nam provided by the Ministry of Agriculture and Rural Development has been implemented from April 2007. One of the program’s project is “Determining the wave heights for sea dyke designed along the coastal line from Quang Ninh to Quang Nam” with the object to propose a method for the calculation of the wave parameters with appropriate accuracy, simple for used and suitable for the natural condition of the different sectors of coastal line of Viet Nam from Quang Ninh to Quang Nam provinces and to upgrade and fulfill the wave calculation guideline for sea dyke design and upgrading. In the paper, the authors present the results of the project concerning the input data, wave models and the calculated wave parameters with different returning periods for 5 sectors along the coastal line from Quang Ninh to Quang Nam. The obtained results afford the promising of using in the sea dyke design and upgrading.

scholarly journals Late Pleistocene Boulder Slumps Eroded from a Basalt Shoreline at El Confital Beach on Gran Canaria (Canary Islands, Spain)

2021 ◽  
Vol 9 (2) ◽  
pp. 138
Author(s):  
Inés Galindo ◽  
Markes E. Johnson ◽  
Esther Martín-González ◽  
Carmen Romero ◽  
Juana Vegas ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Historical Record ◽  
Three Dimensions ◽  
Marine Biota ◽  
Gran Canaria ◽  
Basaltic Rocks ◽  
Individual Wave ◽  
Wave Heights ◽  
Scientific Value ◽  
The Impact

This study examines the role of North Atlantic storms degrading a Late Pleistocene rocky shoreline formed by basaltic rocks overlying hyaloclastite rocks on a small volcanic peninsula connected to Gran Canaria in the central region of the Canary Archipelago. A conglomerate dominated by large, ellipsoidal to angular boulders eroded from an adjacent basalt flow was canvassed at six stations distributed along 800 m of the modern shore at El Confital, on the outskirts of Las Palmas de Gran Canaria. A total of 166 individual basalt cobbles and boulders were systematically measured in three dimensions, providing the database for analyses of variations in clast shape and size. The goal of this study was to apply mathematical equations elaborated after Nott (2003) and subsequent refinements in order to estimate individual wave heights necessary to lift basalt blocks from the layered and joint-bound sea cliffs at El Confital. On average, wave heights in the order of 4.2 to 4.5 m are calculated as having impacted the Late Pleistocene rocky coastline at El Confital, although the largest boulders in excess of 2 m in diameter would have required larger waves for extraction. A review of the fossil marine biota associated with the boulder beds confirms a littoral to very shallow water setting correlated in time with Marine Isotope Stage 5e (Eemian Stage) approximately 125,000 years ago. The historical record of major storms in the regions of the Canary and Azorean islands indicates that events of hurricane strength were likely to have struck El Confital in earlier times. Due to its high scientific value, the outcrop area featured in this study is included in the Spanish Inventory of Geosites and must be properly protected and managed to ensure conservation against the impact of climate change foreseen in coming years.

scholarly journals Long-term spatial variations in the Baltic Sea wave fields

Ocean Science ◽  
2011 ◽  
Vol 7 (1) ◽  
pp. 141-150 ◽  
Author(s):  
T. Soomere ◽  
A. Räämet
Keyword(s):  
Baltic Sea ◽  
Spatial Variations ◽  
Extreme Wave ◽  
The Baltic Sea ◽  
Wave Fields ◽  
Wave Heights ◽  
The Baltic ◽  
Wave Properties ◽  
Sea Wave

Abstract. This study focuses on spatial patterns in linear trends of numerically reconstructed basic wave properties (average and extreme wave heights, wave periods) in the Baltic Sea under the assumption of no ice cover. Numerical simulations of wave conditions for 1970–2007, using the WAM wave model and adjusted geostrophic winds, revealed extensive spatial variations in long-term changes in both average and extreme wave heights in the Baltic Sea but almost no changes in the basinwide wave activity and wave periods. There has been a statistically significant decrease in the annual mean significant wave height by more than 10% between the islands of Öland and Gotland and in the southward sea area, and a substantial increase to the south-west of Bornholm, near the coast of Latvia, between the Åland Archipelago and the Swedish mainland, and between the Bothnian Sea and the Bothnian Bay. Variations in extreme wave heights (defined as the threshold for 1% of the highest waves each year) show similar patterns of changes. In several areas the trends in average and extreme wave heights are different. Such a complicated pattern of changes indicates that (i) different regions of the Baltic Sea basin have experienced widespread but essentially different changes in wind properties and (ii) many seemingly controversial trends and variations established in wave properties at different sites in the recent past may reflect the natural spatial variability in the Baltic Sea wave fields.

scholarly journals Automated classification of the atmospheric circulation patterns that drive regional wave climates

2014 ◽  
Vol 14 (8) ◽  
pp. 2145-2155 ◽  
Author(s):  
J. Pringle ◽  
D. D. Stretch ◽  
A. Bárdossy
Keyword(s):  
Atmospheric Circulation ◽  
Low Pressure ◽  
Wave Climate ◽  
Automated Classification ◽  
Coastal Vulnerability ◽  
Extreme Wave ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Spatially Distributed ◽  
Wave Heights

Abstract. Wave climates are fundamental drivers of coastal vulnerability; changing trends in wave heights, periods and directions can severely impact a coastline. In a diverse storm environment, the changes in these parameters are difficult to detect and quantify. Since wave climates are linked to atmospheric circulation patterns, an automated and objective classification scheme was developed to explore links between synoptic-scale circulation patterns and wave climate variables, specifically wave heights. The algorithm uses a set of objective functions based on wave heights to guide the classification and find atmospheric classes with strong links to wave behaviour. Spatially distributed fuzzy numbers define the classes and are used to detect locally high- and low-pressure anomalies. Classes are derived through a process of simulated annealing. The optimized classification focuses on extreme wave events. The east coast of South Africa was used as a case study. The results show that three dominant patterns drive extreme wave events. The circulation patterns exhibit some seasonality with one pattern present throughout the year. Some 50–80% of the extreme wave events are explained by these three patterns. It is evident that strong low-pressure anomalies east of the country drive a wind towards the KwaZulu-Natal coastline which results in extreme wave conditions. We conclude that the methodology can be used to link circulation patterns to wave heights within a diverse storm environment. The circulation patterns agree with qualitative observations of wave climate drivers. There are applications to the assessment of coastal vulnerability and the management of coastlines worldwide.

scholarly journals Automated classification of the atmospheric circulation patterns that drive regional wave climates

2014 ◽  
Vol 2 (2) ◽  
pp. 1127-1151
Author(s):  
J. Pringle ◽  
D. D. Stretch ◽  
A. Bárdossy
Keyword(s):  
Atmospheric Circulation ◽  
Low Pressure ◽  
Wave Climate ◽  
Automated Classification ◽  
Coastal Vulnerability ◽  
Extreme Wave ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Wave Heights ◽  
Objective Classification

Abstract. Wave climates are fundamental drivers of coastal vulnerability and changing trends in wave height, period and direction can severely impact coastlines. In a diverse storm environment, the changes in these parameters are difficult to detect and quantify. Since wave climates are linked to atmospheric circulation patterns an automated and objective classification scheme was developed to explore links between synoptic scale circulation patterns and wave climate variables, specifically wave heights. The algorithm uses a set of objective functions based on wave heights to guide the classification. Fuzzy rules define classification types that are used to detect locally high and low pressure anomalies through a process of simulated annealing. The optimized classification focuses on extreme wave events. The east coast of South Africa was used as a case study. The results show that three dominant patterns drive extreme wave events. The circulation patterns exhibit some seasonality with one pattern present throughout the year. Some 50–80% of the extreme wave events are explained by these three patterns. It is evident that strong low pressure anomalies east of the country drive a wind towards the KwaZulu-Natal coastline which results in extreme wave conditions. We conclude that the methodology can be used to link circulation patterns to wave heights within a diverse storm environment. The circulation patterns agree with qualitative observations of wave climate drivers. There are applications to the assessment of coastal vulnerability and the management of coastlines worldwide.

Sign in / Sign up

Export Citation Format

Share Document