scholarly journals Wave height and period on 16 March, 21 April, and 22 September 2019, in the Ujung Batee coastal waters and Lampanah coastal waters, Aceh Besar District, Indonesia

2021 ◽  
Vol 869 (1) ◽  
pp. 012040
Author(s):  
I Setiawan ◽  
S M Yuni ◽  
M Ulfah ◽  
S Purnawan ◽  
H A Haridhi ◽  
...  
Keyword(s):  
Wave Height ◽  
Coastal Waters ◽  
Measurement Data ◽  
Research Station ◽  
Wave Data ◽  
Wave Measurements ◽  
Wave Measurement ◽  
Wave Heights ◽  
Station Location ◽  
Sea Wave

Abstract Waves are one of the sea parameters that affect the rate of retreat of the coastline. This research investigation was carried out in the coastal waters of Ujong Batee and Lampanah, Aceh Besar District on 16 March, 21 April, and 22 September 2019, with the aim of examining wave parameters, namely wave height and period. Then the wave measurement data sampled at the research station location was carried out by purposive random sampling method. Sea wave data were taken using a scale board that has been labeled with numbers and a stopwatch. Wave measurements were carried out approximately 1000 times. Then the sea wave data is processed to obtain the wave height and period and then analyzed. The results obtained that the wave heights on 16 March, 21 April, and 22 September 2019 were 67 cm, 83 cm, and 80 cm in Ujong Batee and 55 cm, 67 cm, and 66 cm in Lampanah. While the wave period is 12 seconds on March 16, April 21, and September 22 in Ujong Batee and Lampanah. Thus, the wave height and period at both locations ranged from 50 cm to 80 cm and 12 s.

scholarly journals Comparison of Design Wave Heights Determined on the Basis of Long- and Short-term Measurement Data

2018 ◽  
Vol 65 (2) ◽  
pp. 123-142
Author(s):  
Marek Szmytkiewicz ◽  
Piotr Szmytkiewicz ◽  
Tomasz Marcinkowski
Keyword(s):  
Measurement Data ◽  
Research Station ◽  
Short Term ◽  
Wave Data ◽  
Wave Parameters ◽  
Wave Heights ◽  
Short And Long Term ◽  
Wave Trains ◽  
Coastal Research

AbstractThe objective of this study is to determine differences between design wave heights determined on the basis of short- and long-term wave trains. Wave parameters measured over a period of 7.47 years in the vicinity of Coastal Research Station Lubiatowo were used as short-term wave data, while wave parameters determined through the so-called wave reconstruction for a period of 44 years for the same region and depth were used as long-term wave data. The results of the calculations lead to the conclusions the significant wave height distributions obtained for short and long-term wave data are similar.

An Idealization of Wave Scatter Diagram for Spectral Fatigue Analysis

2009 ◽  
Author(s):  
Min Han Oh ◽  
Ki Myung Lee ◽  
Young Sik Jang
Keyword(s):  
Fatigue Analysis ◽  
Scatter Diagram ◽  
Analysis Method ◽  
Sea State ◽  
Environmental Loads ◽  
Wave Data ◽  
Wave Measurements ◽  
Spectral Models ◽  
Wave Heights ◽  
Significant Wave Heights

A spectral fatigue analysis method is most popularly applied for the detailed design of FPSOs. As the environmental loads at the installation site are directly calculated in the spectral analysis, this method gives the most reliable results although it needs much time-consuming works to fully reflect the environmental loads. As the technology of wave measurements advances, the measured wave data increase. Also their spectral models are very complicated because these include many wave components such as swells and wind seas. Since much time and effort are needed to treat these enormous and complicated wave data for the spectral fatigue analysis, a rational idealization of wave data is definitely required. In this paper, wave scatter diagram at Offshore Nigeria was reviewed and their idealization method was proposed. The influence level of each sea state of the wave scatter diagram was identified considering the fatigue damage levels estimated from the significant wave heights and dominant fatigue load RAOs. The sea states giving small fatigue damages were lumped symmetrically by merging or disregarding while those giving large fatigue damages were kept as original. For the validation of this method, the comparisons of dominant fatigue loads and representative fatigue damages were presented for the idealized wave scatter diagram and the original one. From these comparison works, it was confirmed that the idealized wave scatter diagram gives reliable results with reduced amount of calculation work.

scholarly journals Wave measurements with a modified HydroBall® buoy using different GNSS processing strategies

GEOMATICA ◽  
2019 ◽  
Vol 73 (1) ◽  
pp. 1-14
Author(s):  
Benoit Crépeau Gendron ◽  
Mohamed Ali Chouaer ◽  
Rock Santerre ◽  
Mathieu Rondeau ◽  
Nicolas Seube
Keyword(s):  
Precise Point Positioning ◽  
Reference Station ◽  
Controlled Environment ◽  
Wave Measurements ◽  
Wave Measurement ◽  
Processing Strategies ◽  
Wave Heights ◽  
Kinematic Ppp ◽  
Gnss Processing

One of the CIDCO’s (The Interdisciplinary Center for the Development of Ocean Mapping) HydroBall® GNSS buoys has been specifically adapted to evaluate its potential for wave measurement at centimeter accuracy level. Multiple GNSS processing strategies were tested, namely PPK (Post-Processed Kinematic), PPP (Precise Point Positioning), and TRP (Time Relative Positioning). Experiments were carried out in a hydraulic flume where waves of different amplitudes and periods were generated in a controlled environment. The wave heights obtained by the various GNSS solutions were compared with ultrasonic gauge measurements placed along the flume. The best results were obtained with the PPK and TRP solutions with root mean squared (RMS) values of 2 cm (on average). The main advantages of the TRP solution are that it does not require any reference station nearby (contrary to PPK) or precise ephemerides (required by PPP). A sinusoidal regression comparison of the wave height time series allowed determination of the wave period and amplitude with mean errors of 0.06 s and 0.8 cm, respectively.

Quality Control Issues in Estimating Wave Climate From Hindcast and Satellite Data

2008 ◽  
Author(s):  
Elzbieta M. Bitner-Gregersen ◽  
Cees de Valk
Keyword(s):  
Quality Control ◽  
Wave Height ◽  
Measurement Data ◽  
Building Blocks ◽  
Wave Climate ◽  
Wave Condition ◽  
Wave Hindcast ◽  
Wave Measurements ◽  
Project Site

Accuracy of an estimated design wave condition such as the 100-year significant wave height is important information for risk assessment in design of marine structures. Assessment of accuracy of design conditions is already not simple when they have been derived from in-situ wave measurements at the project site. When using wave hindcast data this task is even less straightforward due to often a lack of sufficiently reliable measurement data near the project site for comparison. Different hindcasts may give significant discrepancies in prediction of extremes. Also, the quality of the hindcast may vary over time. In practice, we often do not much more than illustrating the quality of the data, for example by scatter plots of hindcast data versus measurements far away from the project site. In order to assess the quality of a design wave height from a hindcast systematically, errors in both the local hindcast data and in the extrapolation from these data need to be addressed. The paper discusses the overall idea and some building blocks for such an approach, while realising that there will not be one simple recipe applicable in all situations. One of the issues is the selection and use of observational data in quality control. Satellite wave data are an attractive data source for this purpose. For illustration, data from the seas around Norway are used.

scholarly journals Geologic and Oceanographic Data Determining the "Old Foreshore Zone", of the Heraklion Coastal Area, Crete Island

2013 ◽  
Vol 6 (2) ◽  
pp. 157-166
Keyword(s):  
Wave Height ◽  
Coastal Area ◽  
Field Measurements ◽  
Wave Prediction ◽  
Wave Measurements ◽  
Sea Bottom ◽  
Crete Island ◽  
Wind Measurements ◽  
Run Up ◽  
Sea Wave

Geologic, oceanographic and topographic data and field measurements, of the coastal area in front of Heraklion City, Crete Island, as well as deep sea wave measurements and shallow wave prediction numerical modelling were used for the determination of the 1884 foreshore. Data from numerous drills performed in the coastal area of Heraklion City used for the stratigraphic study of the area. For the calculation of the shallow area wave height, the deep area wave height and wind measurements in the of Cretan Sea were used, as input data of the shallow wave prediction model, taking into account the archive data about the sea bottom bathymetry and the topography of Heraklion area. Then, the maximum wave run up on the coastal area in 1884, which determines the limit of the old foreshore zone was calculated, and the critical requirements of the Act 2971/2001 and the Compulsory Law 2344/1940 "the bigger however unexceptional sea wave run up" were estimated. Finally the innermost limit of the foreshore zone during 1884 was defined, as the 3.5 m level.

Experimental Determination of the Effect of Bow Shape on the Wave Drift Load

2017 ◽  
Author(s):  
Anne Boorsma ◽  
Kees Aalbers ◽  
Riaan van ‘t Veer ◽  
René Huijsmans
Keyword(s):  
Linear Theory ◽  
Wave Height ◽  
Measurement Data ◽  
Ship Motions ◽  
Hull Form ◽  
Small Motion ◽  
Water Line ◽  
Wave Drift ◽  
Wave Heights ◽  
The Mean

In the last forty years wave drift loads have been calculated with methods based on the near-field theory (hull pressure integration, Pinkster [4]) and/or the far field method (linear momentum theory). Both methods use linear theory and through its formulation ignore the ship’s hull form above the mean water line. It is evident that in survival sea-states the small motion assumptions are violated and the hull form above the mean water line can affect the motion characteristics of the ship and the drift loads. In order to get more insight in this effect, SBM has conducted a systematic model test campaign at the TU Delft using an Aframax size tanker. The campaign included tests with two different bow shapes: the original bow with flare, and a wall-sided bow. Horizontal loads on the complete vessel and a section of the bow only were measured accompanied by measurements of the ship motions and relative wave heights. Measurements were performed for various wave heights and periods. Numerous repeat tests were conducted to establish the confidence level of the measurement data. Measurements have shown motions and relative wave heights are dependent on wave height. It was suggested that viscous damping may play a part in this. The relative wave height in high waves is affected by bow shape; namely the finite draft, the flare and the bulb. How this departure from linear theory affects the forces on the vessel should be investigated further.

scholarly journals Surface Wave Measurements from Subsurface Floats

2015 ◽  
Vol 32 (4) ◽  
pp. 816-827 ◽  
Author(s):  
Eric D’Asaro
Keyword(s):  
Surface Wave ◽  
Pressure Gradient ◽  
Surface Waves ◽  
Wave Height ◽  
Vertical Motion ◽  
Sampling Interval ◽  
Height Measurement ◽  
Significant Wave ◽  
Wave Measurements ◽  
Wave Heights

AbstractPressure gradient measurements on a subsurface Lagrangian float are used to measure the spectrum of surface waves for 100 days of measurements at Ocean Weather Station Papa. Along Lagrangian trajectories of surface waves, the pressure is constant and the vertical pressure gradient fluctuations equal the Eulerian fluctuations at the mean float depth to second order in wave height. Measurement of the pressure difference between the top and the bottom of the float can thus be used to measure the waves. Corrections for the wave decay with depth, for the vertical motion of the float, for the finite sampling interval, and for the sampling noise (among others) are necessary to obtain accurate results. With these corrections, scalar spectra accurately match those from a nearby Waverider buoy for significant wave heights greater than about 3 m. For smaller wave heights, noise in the pressure measurements biases the float spectral measurements. Significant wave height is measured with an rms error of 0.37 m over the measured range of 1–9 m. This demonstrates that Lagrangian floats accurately follow the Lagrangian trajectories of surface waves. More detailed and quieter measurements of float motion could likely measure directional wave spectra from below the surface. Similar methods could be used to infer surface wave properties from other subsurface vehicles.

Weather Window Analysis of Irish and Portuguese Wave Data With Relevance to Operations and Maintenance of Marine Renewables

2013 ◽  
Author(s):  
Michael O’Connor ◽  
Tony Lewis ◽  
Gordon Dalton
Keyword(s):  
Wave Height ◽  
Wave Energy ◽  
West Coast ◽  
Atlantic Coast ◽  
The West ◽  
Wave Data ◽  
Window Analysis ◽  
Operations And Maintenance ◽  
Wave Heights ◽  
Waiting Periods

This paper presents the results of a weather window analysis of wave data from the west coast of Ireland and the Atlantic coast of Portugal in order to quantify the levels of access to ocean energy renewables, which may be deployed there, for operation and maintenance activities. In order to operate and maintain offshore marine renewables, a device will have to be accessible for a certain period of time. This will require a weather window consisting of a consecutive period of wave heights low enough and long enough for the device to be accessed. It is important to quantify what the levels of access are off the Irish west coast and Portuguese Atlantic coast given their high wind and wave resource. Wave data from two wave buoys, the M3 buoy located 56km off the west coast of Ireland and the Leixoes buoy located 19km off the Portuguese coast, are analysed to quantify the levels of access that exist. The data is used to quantify the general regimes at both sites by presenting the wave energy resource, the mean annual exceedance and the wave height frequency at both sites. The levels of access are quantified at operations and maintenance (O/M) access limits of Hs 1.0, 1.5, 2.0 and 2.5m wave height, by presenting the number of windows and the percentage of the year that these windows make up as well as the total number of hours, monthly and annual, that the wave heights are below these limits. Also presented are the waiting periods between windows by showing both the longest individual waiting periods between windows in a year and also the total intervals between windows in a year. The levels of access observed off Ireland and Portugal are then compared to levels of access observed at other marine renewable locations, namely the North Sea, Irish East Coast and Pacific North-western US coast. The results indicate that the levels of access off Ireland and Portugal are far below those observed at other marine renewable locations, and at the lower wave height access limits, there are very few suitable weather windows and considerable winter waiting periods between these windows. The implications of these low levels of access suggest that maintaining wave energy converters, off the west coast, may not be feasible and devices will need to be brought ashore for O/M activities.

scholarly journals A Wave Measurements HF Radar Data Set in the Malta-Sicily Channel: Data Quality, Validation and Gap Filling

10.29007/wg8s ◽  
2018 ◽  
Author(s):  
Marco Picone ◽  
Arianna Orasi ◽  
Aldo Drago ◽  
Fulvio Capodici ◽  
Giuseppe Ciraolo ◽  
...  
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Missing Values ◽  
Hf Radar ◽  
Data Set ◽  
Significant Wave ◽  
Wave Data ◽  
Wave Measurements ◽  
Sicily Channel ◽  
Radar Wave

The CALYPSO HF radar network is a permanent and fully operational observing system currently composed of four CODAR HF stations. The system is providing real- time hourly maps of sea surface currents and wave data in the Malta-Sicily Channel since 2012. Significant wave height derived from the HF radar wave measurements are confirmed to be a reliable source of wave information even in case of extreme events. However, it is noticed that the HF radar wave data are subject to differing interfering noise in the signal from unknown sources that may be competing with transmissions in the same frequency band. These interferences lead to frequent gaps and/or outliers that affect the continuity and reliability of the data set. The aim of this work is to estimate missing values and to detect possible outliers building and fitting a Markov chain mixture model on the significant wave height data collected at the four stations. It is verified that the proposed procedure is sufficiently robust since the model estimates succeed to classify radar observations with a high percentage of missing data and to equally highlight spikes and outliers.

scholarly journals Freaque waves during Typhoon Krosa

2009 ◽  
Vol 27 (7) ◽  
pp. 2633-2642 ◽  
Author(s):  
P. C. Liu ◽  
H. S. Chen ◽  
D.-J. Doong ◽  
C. C. Kao ◽  
Y.-J. G. Hsu
Keyword(s):  
North Sea ◽  
Coastal Waters ◽  
Measurement Data ◽  
Conventional Approach ◽  
Wave Measurement ◽  
Further Development

Abstract. This paper presents a subjective search for North Sea Draupner-like freaque waves from wave measurement data available in the northeastern coastal waters of Taiwan during Typhoon Krosa, October 2007. Not knowing what to expect, we found rather astonishingly that there were more Draupner-like freaque wave types during the build-up of the storm than we ever anticipated. As the conventional approach of defining freaque waves as Hmax/Hs>2 is ineffective to discern all the conspicuous cases we found, we also tentatively proposed two new indices based on different empirical wave grouping approaches which hopefully can be used for further development of effective indexing toward identifying freaque waves objectively.

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