scholarly journals Validation of Drifting Buoy Data for Ocean Wave Observation

2021 ◽  
Vol 9 (7) ◽  
pp. 729
Author(s):  
Yukiharu Hisaki
Keyword(s):  
Reference Data ◽  
Wave Data ◽  
Wave Parameters ◽  
Drifting Buoy ◽  
Wave Observation ◽  
Gps Buoy ◽  
Wave Heights ◽  
Buoy Data ◽  
Drifting Buoys ◽  
Better Than

Drifting buoys collect wave data in the open ocean far from land and in areas with strong currents. However, the validation of the drifting buoy wave data is limited. Here, we compared the drifting buoy wave data, ERA5 wave data, and moored GPS buoy wave data. Data from 2009 to 2018 near the coast of Japan were used. The agreement of the drifting buoy-observed wave parameters with the moored GPS buoy-observed wave parameters is better than that of ERA5 wave parameters, which is statistically significant. In particular, the accuracy of the ERA5 wave heights tends to be lower where the ocean currents are fast. On the other hand, the agreement between the drifting buoy-observed wave heights and the moored GPS buoy-observed wave heights was good even in the areas with strong currents. It is confirmed that the drifting buoy wave data can be used as reference data for wave modeling study.

scholarly journals Validation of Sentinel-3A/3B and Jason-3 Altimeter Wind Speeds and Significant Wave Heights Using Buoy and ASCAT Data

2020 ◽  
Vol 12 (13) ◽  
pp. 2079 ◽  
Author(s):  
Jungang Yang ◽  
Jie Zhang ◽  
Yongjun Jia ◽  
Chenqing Fan ◽  
Wei Cui
Keyword(s):  
Ocean Waves ◽  
Global Ocean ◽  
Spatial And Temporal Scales ◽  
Significant Wave ◽  
Wind Speeds ◽  
Wave Heights ◽  
Buoy Data ◽  
Over Time ◽  
Moored Buoy ◽  
Better Than

This study validated wind speed (WS) and significant wave height (SWH) retrievals from the Sentinel-3A/3B and Jason-3 altimeters for the period of data beginning 31 October 2019 (to 18 September 2019 for Jason-3) using moored buoy data and satellite Meteorological Operational Satellite Program (MetOp-A/B) Advanced Scatterometer (ASCAT) data. The spatial and temporal scales of the collocated data were 25 km and 30 min, respectively. The statistical metrics of root mean square error (RMSE), bias, correlation coefficient (R), and scatter index (SI) were used to validate the WS and SWH accuracy. Validation of WS against moored buoy data indicated errors of 1.19 m/s, 1.13 m/s and 1.29 m/s for Sentinel-3A, Sentinel-3B and Jason-3, respectively. The accuracy of Sentinel-3A/3B WS is better than that of Jason-3. All three altimeters underestimated WS slightly in comparison with the buoy data. Errors in WS at different speeds or SWHs increased slightly as WS or SWH increased. Over time, the accuracy of the Jason-3 altimeter-derived WS improved, whereas that of Sentinel-3A showed no temporal dependence. The WSs of the three altimeters were compared with ASCAT wind data for validation purposes over the global ocean without in situ measurements. On average, the WSs of the three altimeters were lower in comparison with the ASCAT data. The accuracy of the three altimeters was found to be consistent and stable at low/medium speeds but it decreased when the WS exceeded 15 m/s. Validations of SWH against buoy wave data indicated that the accuracy of Jason-3 SWH was better than that of Sentinel-3A/3B. However, the accuracy of all three altimeters decreased when the SWH exceeded 4 m. The accuracy of Sentinel-3A and Jason-3 SWH was temporally stable, whereas that of Sentinel-3B SWH improved over time. Analyses of SWH accuracy as a function of wave period showed that the Jason-3 altimeter was better than the Sentinel-3A/3B altimeters for long-period ocean waves. Generally, the accuracy of WS and SWH data derived by the Sentinel-3A/3B and Jason-3 altimeters satisfies their mission requirements. Overall, the accuracy of WS (SWH) derived by Sentinel-3A/3B (Jason-3) is better than that retrieved by Jason-3 (Sentinel-3A/3B).

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.

Measured Metocean Characteristics of Gulf of Mexico Hurricanes

2015 ◽  
Author(s):  
George Z. Forristall ◽  
Jason McConochie
Keyword(s):  
Gulf Of Mexico ◽  
Wave Height ◽  
Storm Track ◽  
Significant Wave ◽  
Wind Speeds ◽  
Hurricane Wind ◽  
Wave Parameters ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Buoy Data

A wealth of Gulf of Mexico hurricane wind and wave data has been measured in recent years. We have constructed a database that combines HURDAT storm track information with NDBC buoy data for the years 1978–2010. HURDAT contains 141 storms for that period of which 67 had measured significant wave heights greater than 5 m. Industry measurements in Hurricanes Camille, Lili, Ivan, Katrina, Rita, Gustav and Ike have been added to the buoy data. We have used this data base to study the relationships between wind and wave parameters in hurricanes. Specifically, we have calculated regressions and equal probability contours for significant wave height and peak spectral periods, first and second moment periods, wave height and Jonswap gamma values, wind speeds and wave heights, and wave and wind directions. All of these calculations have been done for azimuthal quadrants of the storm and radial distances near and far from the storm center.

scholarly journals THREE-WAY ERROR ANALYSIS OF SEA SURFACE TEMPERATURE (SST) BETWEEN HIMAWARI-8, BUOY, AND MUR SST IN SAVU SEA

2018 ◽  
Vol 15 (1) ◽  
pp. 25 ◽  
Author(s):  
Bambang Sukresno ◽  
Rizki Hanintyo ◽  
Denny Wijaya Kusuma ◽  
Dinarika Jatisworo ◽  
Ari Murdimanto
Keyword(s):  
Error Analysis ◽  
Reference Data ◽  
Sea Surface ◽  
Time Data ◽  
Night Time ◽  
Multi Scale ◽  
Level 3 ◽  
Buoy Data ◽  
Better Than

Variance errors of Himawari-8, buoy, and Multi-scale Ultra-high Resolution (MUR) SST in Savu Sea have been investigated. This research used level 3 Himawari-8 hourly SST, in situ measurement of buoy, and daily MUR SST in the period of December 2016 to July 2017. The data were separated into day time data and night time. Skin temperature of Himawari-8 and subskin tempertaure of MUR SST were corrected with the value of 15∆Tdept">  before compared with buoy data. Hourly SST of Himawari-8 and buoy data were converted to daily format by averaging process before collocated with MUR SST data. The number of 2,264 matchup data are obtained. Differences average between Himawari-8, buoy and MUR SST were calculated to get the value of variance (Vij).  Using three-way error analysis, variance errors of each observation type can be known. From the analysis results can be seen that the variance error of Himawari-8, buoy and MUR SST are 2.5 oC, 0.28oC and 1.21oC respectively. The accuracy of buoy data was better than the other. With a small variance errors, thus buoy data can be used as a reference data for validation of SST from different observation type.

scholarly journals Validation of Sentinel-3A/3B Satellite Altimetry Wave Heights with Buoy and Jason-3 Data

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2914 ◽  
Author(s):  
Jungang Yang ◽  
Jie Zhang
Keyword(s):  
Wave Height ◽  
Wave Climate ◽  
Global Ocean ◽  
National Data ◽  
M Wave ◽  
Wave Heights ◽  
Slight Upward Trend ◽  
Buoy Data ◽  
Climate Studies ◽  
Better Than

The validation of significant wave height (SWH) data measured by the Sentinel-3A/3B SAR Altimeter (SRAL) is essential for the application of the data in ocean wave monitoring, forecasting and wave climate studies. Sentinel-3A/3B SWH data are validated by comparisons with U. S. National Data Buoy Center (NDBC) buoys, using a spatial scale of 25 km and a temporal scale of 30 min, and with Jason-3 data at their crossovers, using a time difference of less than 30 min. The comparisons with NDBC buoy data show that the root-mean-square error (RMSE) of Sentinel-3A SWH is 0.30 m, and that of Sentinel-3B is no more than 0.31 m. The pseudo-Low-Resolution Mode (PLRM) SWH is slightly better than that of the Synthetic Aperture Radar (SAR) mode. The statistical analysis of Sentinel-3A/3B SWH in the bin of 0.5 m wave height shows that the accuracy of Sentinel-3A/3B SWH data decreases with increasing wave height. The analysis of the monthly biases and RMSEs of Sentinel-3A SWH shows that Sentinel-3A SWH are stable and have a slight upward trend with time. The comparisons with Jason-3 data show that SWH of Sentinel-3A and Jason-3 are consistent in the global ocean. Finally, the piecewise calibration functions are given for the calibration of Sentinel-3A/3B SWH. The results of the study show that Sentinel-3A/3B SWH data have high accuracy and remain stable.

scholarly journals Wave Height Distributions and Rogue Waves in the Eastern Mediterranean

2021 ◽  
Vol 9 (6) ◽  
pp. 660
Author(s):  
Sagi Knobler ◽  
Daniel Bar ◽  
Rotem Cohen ◽  
Dan Liberzon
Keyword(s):  
Wave Height ◽  
Eastern Mediterranean ◽  
Rogue Waves ◽  
Distribution Model ◽  
Storm Events ◽  
Order Model ◽  
Deep Seawater ◽  
Wave Heights ◽  
Storm Characteristics ◽  
Buoy Data

There is a lack of scientific knowledge about the physical sea characteristics of the eastern part of the Mediterranean Sea. The current work offers a comprehensive view of wave fields in southern Israel waters covering a period between January 2017 and June 2018. The analyzed data were collected by a meteorological buoy providing wind and waves parameters. As expected for this area, the strongest storm events occurred throughout October–April. In this paper, we analyze the buoy data following two main objectives—identifying the most appropriate statistical distribution model and examining wave data in search of rogue wave presence. The objectives were accomplished by comparing a number of models suitable for deep seawater waves. The Tayfun—Fedele 3rd order model showed the best agreement with the tail of the empirical wave heights distribution. Examination of different statistical thresholds for the identification of rogue waves resulted in the detection of 99 unique waves, all of relatively low height, except for one wave that reached 12.2 m in height which was detected during a powerful January 2018 storm. Characteristics of the detected rogue waves were examined, revealing the majority of them presenting crest to trough symmetry. This finding calls for a reevaluation of the crest amplitude being equal to or above 1.25 the significant wave height threshold which assumes rogue waves carry most of their energy in the crest.

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 Characterization of downwelling radiance measured from a ground-based microwave radiometer using numerical weather prediction model data

2016 ◽  
Vol 9 (1) ◽  
pp. 281-293 ◽  
Author(s):  
M.-H. Ahn ◽  
H. Y. Won ◽  
D. Han ◽  
Y.-H. Kim ◽  
J.-C. Ha
Keyword(s):  
Prediction Model ◽  
Numerical Weather Prediction ◽  
Reference Data ◽  
Weather Prediction ◽  
Numerical Weather Prediction Model ◽  
Radiosonde Data ◽  
Absolute Calibration ◽  
Observation Data ◽  
Numerical Weather ◽  
Better Than

Abstract. The ground-based microwave sounding radiometers installed at nine weather stations of Korea Meteorological Administration alongside with the wind profilers have been operating for more than 4 years. Here we apply a process to assess the characteristics of the observation data by comparing the measured brightness temperature (Tb) with reference data. For the current study, the reference data are prepared by the radiative transfer simulation with the temperature and humidity profiles from the numerical weather prediction model instead of the conventional radiosonde data. Based on the 3 years of data, from 2010 to 2012, we were able to characterize the effects of the absolute calibration on the quality of the measured Tb. We also showed that when clouds are present the comparison with the model has a high variability due to presence of cloud liquid water therefore making cloudy data not suitable for assessment of the radiometer's performance. Finally we showed that differences between modeled and measured brightness temperatures are unlikely due to a shift in the selection of the center frequency but more likely due to spectroscopy issues in the wings of the 60 GHz absorption band. With a proper consideration of data affected by these two effects, it is shown that there is an excellent agreement between the measured and simulated Tb. The regression coefficients are better than 0.97 along with the bias value of better than 1.0 K except for the 52.28 GHz channel which shows a rather large bias and variability of −2.6 and 1.8 K, respectively.

Prévision des vagues dans l'estuaire du Saint-Laurent à l'aide d'un modèle bidimensionnel

1999 ◽  
Vol 26 (6) ◽  
pp. 713-723 ◽  
Author(s):  
L Dupuis ◽  
Y Ouellet
Keyword(s):  
Water Waves ◽  
Wave Climate ◽  
Wave Direction ◽  
Limited Region ◽  
Lawrence Estuary ◽  
Wave Data ◽  
Modèle Bidimensionnel ◽  
Wave Heights ◽  
Wave Hindcasting ◽  
2D Model

Until now, wave hindcasting in the Estuary and Gulf of St. Lawrence has been done with one-dimensional models. The objective of the present paper is to verify if the two-dimensional model WAWSP, developed to predict waves on the Great Lakes, could be used in the St. Lawrence estuary, a semi-open fetch limited region. Waves (significant wave heights, peak periods, and directions) hindcast by this 2D model are compared with wave data observed at two buoys in 1991, 1992, and 1993, as well as with the ones obtained with 1D models SPM-77 and SPM-84. As a whole, the 2D model gives better results than 1D models. Wave heights are well reproduced, as long as wind data are well represented. However, wave periods are much smaller than those measured, and wave directions are not accurate, mainly because of the presence of swell in the estuary. This study shows the need to obtain more wave data with better quality in order to validate wave hindcasting models.Key words: water waves, numerical modeling, wave hindcasting, 2D model, wave climate, wave height, wave period, wave direction, calculated versus measured waves.

STATISTIC STUDY ON JOINT DISTRIBUTION OF OFFSHORE WAVES AND WINDS IN JAPAN USING NOWPHAS GPS BUOY DATA

2013 ◽  
Author(s):  
Toshihiko Nagai ◽  
Koji Kawaguchi ◽  
Yutaka Yoshimura ◽  
Takeshi Yoshioka ◽  
Ryoichi Tanikawa ◽  
...  
Keyword(s):  
Joint Distribution ◽  
Gps Buoy ◽  
Statistic Study ◽  
Buoy Data
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