Evaluation of hydromorphological conditions of Grand Popo Beach using two unique video cameras

2021 ◽  
pp. 1-36
Author(s):  
KoueKam K. Arnaud ◽  
Frédéric Bonou ◽  
Zacharie Sohou ◽  
Donatus B. Angnuureng ◽  
Rafael Almar
Keyword(s):  
Video Camera ◽  
Spatial And Temporal Patterns ◽  
Peak Period ◽  
Video Cameras ◽  
Significant Wave ◽  
Wave Heights ◽  
Wave Energy Flux ◽  
Significant Wave Heights ◽  
Erosion And Accretion ◽  
The Impact

Beaches are characterized by complex spatial and temporal patterns of erosion and accretion subjected to significant wave and tide influence. The objective of this study is to estimate the evolution of hydromorphodynamic conditions on the shoreline of Grand Popo Beach observed from two adjacent video camera setups. We have analyzed the impact of the variability of hydrodynamic parameters on the beach evolution and evaluated the variabilities of the hydrodynamic and morphologic parameters from the two cameras. Despite the nonhomogeneity within the cameras’ intrinsic properties, the various results obtained from the two systems indicate that wave conditions (peak period and significant height) from the cameras have the same variations, whereas the shoreline variations of camera A are not the same as those of camera B. It is generally during the summer that the Grand Popo Beach is exposed to an agitated environment with strong observed values of significant wave heights and wave energy flux, undoubtedly resulting in significant sediment transport along the beach leading a shoreline retreat. The results indicate that in 3.5 years the shoreline of Grand Popo Beach has retreated by 10 m.

scholarly journals Wave directional measurement in Patos Lagoon, RS, Brazil

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Natália Lemke ◽  
◽  
Lauro Julio Calliari ◽  
José Antônio Scotti Fontoura ◽  
Déborah Fonseca Aguiar
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Wave Climate ◽  
Coastal Protection ◽  
Peak Period ◽  
Patos Lagoon ◽  
Significant Wave ◽  
Wave Parameters ◽  
Wave Heights ◽  
Significant Wave Heights

ABSTRACT The wave climate characterization in coastal environments is essentially important to oceanography and coastal engineering professionals regarding coastal protection works. Thus, this study aims to determine the most frequent wave parameters (significant wave height, peak period and peak direction) in Patos Lagoon during the period of operation of a directional waverider buoy (from 01/27/2015 to 06/30/2015). The equipment was moored at approximately 14 km from the São Lourenço do Sul coast at the geographic coordinates of 31º29’06” S and 51º55’07” W, with local depth of six meters, registering significant wave height, peak period and peak direction time series. During the analyzed period, the greatest wave frequencies corresponded to short periods (between 2 and 3.5 seconds) and small values of significant wave heights (up to 0.6 meters), with east peak wave directions. The largest wave occurrences corresponded to east peak wave directions (33.3%); peak wave periods between 2.5 and 3 seconds (25.6%) and between 3 and 3.5 seconds (22.1%); and to significant wave heights of up to 0.3 meters (41.2%) and from 0.3 to 0.6 meters (38%). This research yielded unprecedented findings to Patos Lagoon by describing in detail the most occurring wave parameters during the analyzed period, establishing a consistent basis for several other studies that might still be conducted by the scientific community.

scholarly journals Updating knowledge of cyclonic wave hazard for Tahiti and Moorea Islands (French Polynesia) through a probabilistic approach

2014 ◽  
Vol 2 (1) ◽  
pp. 725-756
Author(s):  
S. Lecacheux ◽  
T. Bulteau ◽  
R. Pedreros
Keyword(s):  
Numerical Models ◽  
Probabilistic Approach ◽  
French Polynesia ◽  
Extreme Wave ◽  
Peak Period ◽  
Significant Wave ◽  
Wave Characteristics ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Propagation Of Waves

Abstract. This paper intends to reevaluate cyclonic wave scenarios used for hazard studies for two French Polynesian Islands (Tahiti and Moorea) with a combination of expertise and probabilistic analysis. The method entails (1) constituting a set of cyclones based on both historical data and synthetic events obtained by translating real historical tracks (2) computing the coastal wave characteristics all around the islands for each cyclone with numerical models (3) performing a statistical analysis on the model outputs and determining orders of magnitude of 10 and 100 yr wave characteristics (significant wave height: SWH, and peak period: Tp) for the different sectors of the islands. The results show that if the western and southwestern coasts are more exposed to frequent cyclonic events (with 10 yr SWH up to 5 m and associated Tp up to 16 s), the northern coasts are the most vulnerable if a cyclone pass very close to the islands because they face the main direction of propagation of waves. For these coasts, the 100 yr SWH can reach 12 m with Tp around 12 s. On the contrary, southern coasts are the least exposed to extreme wave heights with 100 yr SWH below 7 m and associated Tp around 10 s. However, southern coasts can also be affected by very long southern waves all year long (100 yr SWH around 5 m and Tp up to 15 s) that can have similar effects than cyclonic waves at the coast. Although these results are associated with high uncertainties related to the restricted sample of cyclones used, they provide realistic and rational orders of magnitude of cyclonic significant wave heights and associated periods for different return periods, taking into account the alongshore variability in wave exposure around the islands.

scholarly journals Numerical Study on Spatio-Temporal Distribution of Cold Front-Induced Waves along the Southeastern Coast of China

2021 ◽  
Vol 9 (12) ◽  
pp. 1452
Author(s):  
Pinyan Xu ◽  
Yunfei Du ◽  
Qiao Zheng ◽  
Zhumei Che ◽  
Jicai Zhang
Keyword(s):  
Wind Direction ◽  
Cold Front ◽  
Numerical Study ◽  
Ocean Waves ◽  
Extreme Weather Events ◽  
Significant Wave ◽  
Cold Fronts ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
The Impact

Cold fronts, as one of the most frequent extreme weather events, can induce significant waves on the sea. This work analyzes the spatial and temporal variations in cold front events, especially the characteristics of wind directions during cold fronts in the East China Sea (ECS). The SWAN (Simulating Waves Nearshore) model is applied to simulating the waves induced by cold fronts. To calibrate the model, two typical cold front events were selected to simulate the corresponding waves in the ECS. The results indicate that the data misfit between the observed and modeled significant wave heights (SWH) is within a reasonable range. Idealized sensitivity experiments were then designed in order to analyze and discuss the responses of ocean waves to wind direction, swell distribution, maximum of significant wave heights (MSWH), and time lag during the cold fronts. The results show that the average MSWH in the ECS decreases monotonically with the deflection of wind direction from north-east to north-west, while specific nearshore sites do not conform to this pattern due to topography. The time series of SWH indicate that the action of the swells leads to a prolongation of the duration of catastrophic waves. This work investigates the temporal and spatial distribution characteristics of cold front-induced wind wave fields in offshore Zhejiang, which has important value for the study of the impact of cold fronts on the ocean as well as disaster prevention and mitigation efforts.

scholarly journals Comprehensive Wind and Wave Statistics and Extreme Values for Design and Analysis of Marine Structures in the Adriatic Sea

2021 ◽  
Vol 9 (5) ◽  
pp. 522
Author(s):  
Marko Katalinić ◽  
Joško Parunov
Keyword(s):  
Adriatic Sea ◽  
Extreme Values ◽  
Wave Climate ◽  
Offshore Structures ◽  
Model Parameters ◽  
Peak Period ◽  
Significant Wave ◽  
Wave Statistics ◽  
Wave Heights ◽  
Almost All

Wind and waves present the main causes of environmental loading on seagoing ships and offshore structures. Thus, its detailed understanding can improve the design and maintenance of these structures. Wind and wave statistical models are developed based on the WorldWaves database for the Adriatic Sea: for the entire Adriatic Sea as a whole, divided into three regions and for 39 uniformly spaced locations across the offshore Adriatic. Model parameters are fitted and presented for each case, following the conditional modelling approach, i.e., the marginal distribution of significant wave height and conditional distribution of peak period and wind speed. Extreme significant wave heights were evaluated for 20-, 50- and 100-year return periods. The presented data provide a consistent and comprehensive description of metocean (wind and wave) climate in the Adriatic Sea that can serve as input for almost all kind of analyses of ships and offshore structures.

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