scholarly journals Performance Assessment of ERA5 Wave Data in a Swell Dominated Region

2020 ◽  
Vol 8 (3) ◽  
pp. 214 ◽  
Author(s):  
Maria Francesca Bruno ◽  
Matteo Gianluca Molfetta ◽  
Vincenzo Totaro ◽  
Michele Mossa
Keyword(s):  
Performance Assessment ◽  
Monsoon Season ◽  
Wind Waves ◽  
Wave Model ◽  
Ocean Basin ◽  
Evaluation Framework ◽  
Model Assessment ◽  
Partition Scheme ◽  
Wave Data ◽  
Wave Characteristics

The present paper deals with a performance assessment of the ERA5 wave dataset in an ocean basin where local wind waves superimpose on swell waves. The evaluation framework relies on observed wave data collected during a coastal experimental campaign carried out offshore of the southern Oman coast in the Western Arabian Sea. The applied procedure requires a detailed investigation on the observed waves, and aims at classifying wave regimes: observed wave spectra have been split using a 2D partition scheme and wave characteristics have been evaluated for each wave component. Once the wave climate was defined, a detailed wave model assessment was performed. The results revealed that during the analyzed time span the ERA5 wave model overestimates the swell wave heights, whereas the wind waves’ height prediction is highly influenced by the wave developing conditions. The collected field dataset is also useful for a discussion on spectral wave characteristics during monsoon and post-monsoon season in the examined region; the recorded wave data do not suffice yet to adequately describe wave fields generated by the interaction of monsoon and local winds.

scholarly journals THE CHARACTERISTICS OF WIND-WAVES GENERATED IN THE LABORATORY

1968 ◽  
Vol 1 (11) ◽  
pp. 4
Author(s):  
Theodore E. Lee
Keyword(s):  
Wind Wave ◽  
Wind Waves ◽  
Ocean Waves ◽  
Coastal Engineering ◽  
Wave Period ◽  
Zero Crossing ◽  
Wave Data ◽  
Wave Characteristics ◽  
Significant Correction ◽  
Wave Heights

Wind-wave characteristics were recorded in the laboratory for the primary purposes of (a) analysis of the probability distribution of wave height and wave period with wind speed, water depth, and fetch length as major parameters, and (b) comparison of the test results with existing theory and empirical formulae. An important aspect of this study was to test the validity of the Tucker and Draper method (Draper, 1966) for the presentation of ocean wave data as applicable to wave-data analysis for simulated wind waves. It was interesting to note that some corrections were necessary when the method proposed by Draper at the 10th Coastal Engineering Conference was used for analyzing waves generated in the laboratory. Approximately a positive 20% correction was necessary for this study in which the wave spectra distribution is of very narrow range, the wave width parametere = V1-(T /T ) varles from 0.25 to 0.50, where Tc and T2 represent crest wave period ana zero-crossing wave period, respectively. However, only a negative 5% correction was necessary when the method was used to analyze sea waves (e = 0 73 to 0 76) measured off the shoreline near Look Laboratory Therefore, it was concluded that the Tucker and Draper Method is quite feasible for engineering purposes in analyzing wind-waves having a spectral width parameter of 0.60 to 0.75 The experimental data were compared with those wave heights predicted by the Darbyshire formulas (Francis, 1959) developed for ocean waves. A significant correction factor was necessary for laboratory waves produced by low-speed wi nds. The "fetch graph" was prepared and compared with those developed theoretically by Hino (1966) and empirically by Ijima and Tang (1966) at the 10th Conference on Coastal Engineering, Tokyo, Japan Comparison was also made with the previous empirical formulae by Bretschneider (1951, 1957), Sverdrup and Munk (1947), and Wilson (1961,1962). The experimental results compared well with the Hino theory for both wave heights and wave periods, and fairly well with Bretschneider's fetch graph for wave heights The difference in the comparison of wave data with other investigators is illustrated in this paper. It is recommended that further study be made with emphasis on (a) theoretical and experimental studies of wind-wave characteristics on pre-existing waves, particularly moving storms, (b) wave-energy spectra involving stochastic characteristics and extreme values of wind waves

scholarly journals Regional Downscaling of Copernicus ERA5 Wave Data for Coastal Engineering Activities and Operational Coastal Services

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 859
Author(s):  
Giorgio Bellotti ◽  
Leopoldo Franco ◽  
Claudia Cecioni
Keyword(s):  
Time Series ◽  
National Level ◽  
Wave Model ◽  
Wave Climate ◽  
Tyrrhenian Sea ◽  
Computational Domain ◽  
Multiple Wave ◽  
Space Resolution ◽  
Wave Data ◽  
Fundamental Information

Hindcasted wind and wave data, available on a coarse resolution global grid (Copernicus ERA5 dataset), are downscaled by means of the numerical model SWAN (simulating waves in the nearshore) to produce time series of wave conditions at a high resolution along the Italian coasts in the central Tyrrhenian Sea. In order to achieve the proper spatial resolution along the coast, the finite element version of the model is used. Wave data time series at the ERA5 grid are used to specify boundary conditions for the wave model at the offshore sides of the computational domain. The wind field is fed to the model to account for local wave generation. The modeled sea states are compared against the multiple wave records available in the area, in order to calibrate and validate the model. The model results are in quite good agreement with direct measurements, both in terms of wave climate and wave extremes. The results show that using the present modeling chain, it is possible to build a reliable nearshore wave parameters database with high space resolution. Such a database, once prepared for coastal areas, possibly at the national level, can be of high value for many engineering activities related to coastal area management, and can be useful to provide fundamental information for the development of operational coastal services.

scholarly journals Hurricane Gustav (2008) Waves and Storm Surge: Hindcast, Synoptic Analysis, and Validation in Southern Louisiana

2011 ◽  
Vol 139 (8) ◽  
pp. 2488-2522 ◽  
Author(s):  
J. C. Dietrich ◽  
J. J. Westerink ◽  
A. B. Kennedy ◽  
J. M. Smith ◽  
R. E. Jensen ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Hurricane Katrina ◽  
Storm Surge ◽  
Unstructured Mesh ◽  
Wind Waves ◽  
Wave Model ◽  
Small Scale ◽  
Research Division ◽  
Time Histories ◽  
Southern Louisiana

AbstractHurricane Gustav (2008) made landfall in southern Louisiana on 1 September 2008 with its eye never closer than 75 km to New Orleans, but its waves and storm surge threatened to flood the city. Easterly tropical-storm-strength winds impacted the region east of the Mississippi River for 12–15 h, allowing for early surge to develop up to 3.5 m there and enter the river and the city’s navigation canals. During landfall, winds shifted from easterly to southerly, resulting in late surge development and propagation over more than 70 km of marshes on the river’s west bank, over more than 40 km of Caernarvon marsh on the east bank, and into Lake Pontchartrain to the north. Wind waves with estimated significant heights of 15 m developed in the deep Gulf of Mexico but were reduced in size once they reached the continental shelf. The barrier islands further dissipated the waves, and locally generated seas existed behind these effective breaking zones.The hardening and innovative deployment of gauges since Hurricane Katrina (2005) resulted in a wealth of measured data for Gustav. A total of 39 wind wave time histories, 362 water level time histories, and 82 high water marks were available to describe the event. Computational models—including a structured-mesh deepwater wave model (WAM) and a nearshore steady-state wave (STWAVE) model, as well as an unstructured-mesh “simulating waves nearshore” (SWAN) wave model and an advanced circulation (ADCIRC) model—resolve the region with unprecedented levels of detail, with an unstructured mesh spacing of 100–200 m in the wave-breaking zones and 20–50 m in the small-scale channels. Data-assimilated winds were applied using NOAA’s Hurricane Research Division Wind Analysis System (H*Wind) and Interactive Objective Kinematic Analysis (IOKA) procedures. Wave and surge computations from these models are validated comprehensively at the measurement locations ranging from the deep Gulf of Mexico and along the coast to the rivers and floodplains of southern Louisiana and are described and quantified within the context of the evolution of the storm.

scholarly journals Non-linear wave data assimilation with an ANN-type wind-wave model and Ensemble Kalman Filter (EnKF)

2010 ◽  
Vol 34 (8) ◽  
pp. 1984-1999 ◽  
Author(s):  
Ahmadreza Zamani ◽  
Ahmadreza Azimian ◽  
Arnold Heemink ◽  
Dimitri Solomatine
Keyword(s):  
Kalman Filter ◽  
Data Assimilation ◽  
Ensemble Kalman Filter ◽  
Wind Wave ◽  
Wave Model ◽  
Linear Wave ◽  
Wave Data ◽  
Non Linear

Hydrodynamic Сonditions of the Bakalskaya Spit Degradation (Western Crimea) over the Past 30 Years

2021 ◽  
Vol 37 (3) ◽  
Author(s):  
B. V. Divinsky ◽  
R. D. Kosyan ◽  
◽  
Keyword(s):  
Discriminant Analysis ◽  
Coastal Zone ◽  
Satellite Images ◽  
Wind Waves ◽  
Total Duration ◽  
Wave Model ◽  
Statistical Characteristics ◽  
Wave Impact ◽  
Annual Variability ◽  
The Impact

Purpose. The paper is aimed at studying the morphodynamic features of the Bakalskaya Spit evolution being influenced by the sea wind waves and swell, namely assessment of inter-annual variations in the alluvial (erosion) areas of the Bakalskaya Spit coastline, analysis of inter-annual variability of the wind wave parameters, determination of the surface wave characteristics (or a combination of a few ones) responsible for the processes of the bottom material erosion or accumulation in the coastal zone. Methods and Results. Based on the analysis of satellite images for 1984–2016, the areas of the bottom material accumulation or erosion of the Bakalskaya Spit coastline were determined. Application of the spectral wave model permitted to obtain time series of the main parameters of wind waves and swell (significant wave heights and propagation directions) in the Bakalskaya Spit coastal zone with the 1 hr time resolution for the period from 1984 to 2016. The characteristics of surface waves responsible for the coastline deformation were revealed using the discriminant analysis. Conclusions. Analysis of satellite images of the spit made it possible to distinguish three periods in the history of the Bakalskaya Spit evolution: 1985–1997, 1998–2007 and 2007–2016. The first period was characterized by relative stability. The strongest erosion took place in 1998; after that the alluvial and erosion cases alternated for 10 years weakly tending to general erosion that constituted the second period. The third one that began in 2007 can be defined as the period of spit degradation accompanied by the irreversible loss of beach material. The basic parameters conditioning hydrodynamics of the Bakalskaya Spit water area are: total duration of storms; average and maximum values of significant heights of wind waves and swell. Statistical characteristics of the wind waves’ parameters are of a fairly strong inter-annual variability. According to the average and maximum indices, the wind waves directed close to the normal to the coastline (WSW and WNW) are the most developed. The applied discriminant analysis permitted to draw a statistically reliable conclusion that the direction of the final (average annual) wave impact on the coastal zone, conditioning the processes of sand accumulation or erosion was set by the waves directed to NNW, at that the swell contribution was dominant. The impact degree is conditioned by strong storms with the directions close to the normal to the coastline, namely, the WSW ones

Variational Wave Data Assimilation in a Third-Generation Wave Model

1994 ◽  
Vol 11 (5) ◽  
pp. 1350-1369 ◽  
Author(s):  
Miriam M. De Las Heras ◽  
Gerrit Burgers ◽  
Peter A. E. M. Janssen
Keyword(s):  
Data Assimilation ◽  
Wave Model ◽  
Third Generation ◽  
Wave Data ◽  
Variational Wave

scholarly journals Marine Heatwaves in the Arabian Sea

2021 ◽  
Author(s):  
Abhisek Chatterjee ◽  
Gouri Anil ◽  
Lakshmi R. Shenoy
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Heat Budget ◽  
Monsoon Season ◽  
Fold Increase ◽  
Recent Decade ◽  
Ocean Basin ◽  
Significant Heterogeneity ◽  
Indian Ocean Basin Mode ◽  
Budget Analysis

Abstract. Marine heatwaves (MHWs) are prolonged warm sea condition events that cause a destructive impact on marine ecosystems. The documentation of MHWs and assessment of their impacts are largely confined to a few regional seas or in global mean studies. The Indian Ocean received almost no attention in this regard despite the fact that this ocean basin, particularly the Arabian Sea, is warming at the most rapid pace among the other tropical basins in recent decades. This study shows the characteristics MHWs for the Arabian Sea during 1982–2019. Our analysis shows that the duration of MHWs exhibit a rapidly increasing trend of ~20 days/decade (1.5–2 count/decade) in the northern Arabian Sea and in the southeastern Arabian Sea close to the west coast of India; which is more than 15 fold increase in the MHW days from the early 80s'. At the same time increase in MHW frequency is ~1.5–2 count/decade i.e an increase of ~6 fold, indicating more frequent and much longer heatwave events in the recent decade. Notably, since the beginning of the satellite record, the year 2010 and 2016 saw the maximum number of heatwave days with more than 75 % of days of the pre-monsoon and summer monsoon season experienced heatwaves. The accelerated trend of the heatwave days is found to be driven by the rapid rise of the mean SST of the Arabian Sea in the recent decade. Moreover, longer heatwave days are also associated with the dominant climate modes and among them, Indian Ocean Basin mode via the decaying phase of the El-Niño is found to be the most influencing mode contributing in more than 70–80 % of observed heatwave days in this basin. Mixed layer heat budget analysis suggests significant heterogeneity in the dominant processes across the years; however, weakening of latent heat loss is in general one of the key mechanism in the genesis of most of the MHWs.

scholarly journals Monitoring and Analysis of Wave Characteristics during Pipeline End Termination Installation

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 569
Author(s):  
Duanfeng Han ◽  
Ting Cui ◽  
Lihao Yuan ◽  
Yingfei Zan ◽  
Zhaohui Wu
Keyword(s):  
Real Time ◽  
Wave Motion ◽  
Fourier Transforms ◽  
Classical Method ◽  
Suitable Model ◽  
Wave Data ◽  
Wave Characteristics ◽  
Environmental Monitoring System ◽  
Spreading Function ◽  
Marine Environmental

Pipeline end termination (PLET) installation is an essential part of offshore pipe-laying operation. Pipe-laying operations are sensitive to pipe-laying barge motion and marine environmental conditions. Monitoring the field environment can provide a reasonable basis for planning pipe-laying. Therefore, the measurement and analysis of sea wave motion is helpful for the control and operational safety of the pipeline and vessels. In this study, an environmental monitoring system was established to measure wave motion during PLET operation. Fourier transforms were used to process images that were acquired by ultra-high-frequency X-band marine radar to extract wave parameters. The resulting wave spectra, as measured each minute, were used to simulate real-time wave data and calculate wave characteristics and regressed wave frequency and direction spectrum throughout the PLET operation. The regressed frequency, spectral density, and direction spectra were compared with the theoretical spectra to evaluate their similarity and find the most similar spreading function in the operational area (the South China Sea). Gaussian fitting of real-time wave data was tested while using a classical method. The marginal distribution and joint density of the wave characteristics were estimated and then compared with theoretical distributions to find the most suitable model for improving marine environmental forecasting.

Wind waves modeling in the polar law weather conditions

2020 ◽  
Author(s):  
Alexandra Kuznetsova ◽  
Evgeny Poplavsky ◽  
Nikita Rusakov ◽  
Yuliya Troitskaya
Keyword(s):  
Wind Waves ◽  
Rapid Development ◽  
Free Water ◽  
Wave Model ◽  
Weather Conditions ◽  
Reanalysis Data ◽  
The Arctic ◽  
Geophysical Research ◽  
Polar Lows ◽  
Adverse Weather

<p>Arctic storms pose a great danger to developing commercial and passenger shipping, coastal infrastructure, and also for oil production from offshore platforms. This is primarily due to high waves and extreme winds. Such episodes of adverse weather conditions due to their rapid development are poorly predicted by modern models. For this purpose, the representation of the event of polar law is studied in the wave model WAVEWATCH III.</p><p>Wind waves were simulated under conditions of polar depression on ice-free water. To simulate wind waves under conditions of polar depression, the Barents Sea was selected, where, according to the data of [1, 2], a large number of polar hurricanes are observed. Among the identified polar hurricanes, for example, in [3], a hurricane that took place on 05.02.2009, observed at coordinates 69 N 40 E is chosen. The preliminary results in the wave model are obtained without the ice influence consideration. The developed model was configured using the CFSR wind reanalysis data. The resulting distribution of significant wave heights is obtained. Then, to consider the attenuation by sea ice, the reanalysis data of the Arctic System Reanalysis Version 2 (ASRv2), which is based on Polar WRF with a resolution of 15 km for the Arctic region, is used. Modeling the destruction of ice by waves during an intense arctic storm will be implemented using WW3 models with an IS2 module.</p><p>The work is supported by RFBR grant 18-05-60299.</p><ol><li>Smirnova, J. E., Golubkin, P. A., Bobylev, L. P., Zabolotskikh, E. V., & Chapron, B. (2015). Polar low climatology over the Nordic and Barents seas based on satellite passive microwave data. Geophysical Research Letters, 42(13), 5603-5609.</li> <li>Smirnova, J., & Golubkin, P. (2017). Comparing polar lows in atmospheric reanalyses: Arctic System Reanalysis versus ERA-Interim. Monthly Weather Review, 145(6), 2375-2383.</li> <li>Noer, G., & Lien, T. (2010). Dates and Positions of Polar lows over the Nordic Seas between 2000 and 2010. Norwegian Meteorological Institute Rep.</li> </ol>

Calibration of SWAN Model for Wave Simulation in Bohai Sea

2013 ◽  
Vol 423-426 ◽  
pp. 1344-1350
Author(s):  
Xiang Cui Lv ◽  
Dao Sheng Wang ◽  
De Kui Yuan ◽  
Jian Hua Tao
Keyword(s):  
Water Waves ◽  
Bohai Sea ◽  
Sensitivity Analyses ◽  
Short Term ◽  
Wave Source ◽  
The Bohai Sea ◽  
Swan Model ◽  
Wave Data ◽  
Wave Characteristics

It is necessary to obtain a further understanding of the behaviors and characteristics of water waves in the Bohai Sea for the coastal engineering construction and environment protection in this area. The SWAN (Simulating Waves Nearshore) model, a third-generation wave spectral model on the basis of wave action conservation has been applied to study the water waves in the Bohai Sea by several researchers, and encouraging results have been obtained. However, the calibrated parameter for a wave process at an individual station does not have universal applicability for other stations, which causing problems to anyalyze the wave characteristics in the Bohai Sea. Thus, in this study how to calibrate the SWAN model in the Bohai Sea was analyzed carefully in terms of five sets of short-term wave data and one set of long-term wave data at Tanggu. It was found that wind, whitecapping, bottom mechanisms of wave source function and tide current are the four main factors in the process of wave development. A set of optimized parameters suitable for both long-term and short-term wave processes in the Bohai Sea is suggested through the sensitivity analyses of these elements. Comparisons between the simulated results and the field measured data show that the validated model can provide more accurate results for both long-term and short-term simulations and can be used to study the wave characteristics in the Bohai Sea.

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