A global high-resolution ocean wave model improved by assimilating the satellite altimeter significant wave height

Author(s):  
Huaming Yu ◽  
Jiangyu Li ◽  
Kejian Wu ◽  
Zhifeng Wang ◽  
Haiqing Yu ◽  
...  
1995 ◽  
Vol 117 (4) ◽  
pp. 294-297 ◽  
Author(s):  
J. C. Teixeira ◽  
M. P. Abreu ◽  
C. Guedes Soares

Two wind models were developed and their results were compared with data gathered during the Wangara experiment, so as to characterize their uncertainty. One of the models was adopted to generate the wind fields used as input to a second generation wave model. The relative error in the wind speed was considered in order to assess the uncertainties of the predictions or the significant wave height. Different time steps for the wind input were also used to determine their effect on the predicted significant wave height.


Author(s):  
Johannes Schulz-Stellenfleth ◽  
Susanne Lehner ◽  
Thomas Ko¨nig ◽  
Stephan Brusch

It is well known that satellite radar systems as flown on the ERS-2 or ENVISAT satellite are capable of providing high resolution information on the near surface ocean wind field and ocean waves independent of light or cloud conditions. In this presentation an overview is given of the retrieval of different geophysical parameters which are relevant for the optimal siting, the design and the operation of offshore wind farms and wave energy plants. Different examples of high resolution wind fields acquired over the wind parks “Horns Rev” and “Butendiek” in the North Sea are presented. Both image mode scenes of 100 km by 100 km size as well as wide swath images of 500 km by 500 km size are used for the investigation. Special emphasis is put on the use of the radar data for the analysis of small scale atmospheric phenomena like shadowing or turbulence as well as the estimation of ocean wave parameters like the significant wave height. High resolution maps of ocean wave parameters like significant wave height or wave period are presented. The presentation will also include the application of more sophisticated techniques like the use of Dual-Polarisation data available from ENVISAT. The final part of the presentation will deal with the next generation radar satellite TerraSAR-X launched in 2007. The spatial resolution of this instrument is in the order of 1 m, which is an order of magnitude better than the ENVISAT and ERS satellites used up to now. It has furthermore interferometric capabilities, which enable the derivation of ocean current information. The potential as well as the limitations of this new instrument with respect to the offshore windfarming and wave farming sector will be discussed.


Author(s):  
Adil Rasheed ◽  
Jakob Kristoffer Süld ◽  
Mandar Tabib

Accurate prediction of near surface wind and wave height are important for many offshore activities like fishing, boating, surfing, installation and maintenance of marine structures. The current work investigates the use of different methodologies to make accurate predictions of significant wave height and local wind. The methodology consists of coupling an atmospheric code HARMONIE and a wave model WAM. Two different kinds of coupling methodologies: unidirectional and bidirectional coupling are tested. While in Unidirectional coupling only the effects of atmosphere on ocean surface are taken into account, in bidirectional coupling the effects of ocean surface on the atmosphere are also accounted for. The predicted values of wave height and local wind at 10m above the ocean surface using both the methodologies are compared against observation data. The results show that during windy conditions, a bidirectional coupling methodology has better prediction capability.


2015 ◽  
Vol 74 (5) ◽  
Author(s):  
Muhammad Zikra ◽  
Noriaki Hashimoto ◽  
Kodama Mitsuyasu ◽  
Kriyo Sambodho

Over recent years, ocean wave climate change due to global warming has attracted a lot of attention not only coastal and offshore engineer but also stakeholders in the marine industry. There is a wide range of application in ocean environment that require information on ocean wave climate data, such as ships design, design of offshore platforms and coastal structures or naval industry. In this research, monthly variation in significant wave height is studied using MRI-AGCM3.2 wind climate data for 25 year period from 1979-2003. The 25 year significant wave height simulation derived from JMA/MRI-AGCM wind climate data. The JMA/MRI-AGCM climate data were input into WAM model. The results showed that the monthly variability of significant wave height in the Northern Hemisphere is greater than in the Southern Hemisphere. Meanwhile, most of the equatorial regions are in calm condition all year. 


2021 ◽  
Vol 13 (19) ◽  
pp. 3833
Author(s):  
Meng Sun ◽  
Jianting Du ◽  
Yongzeng Yang ◽  
Xunqiang Yin

Accurate numerical simulation of ocean waves is one of the most important measures to ensure shipping safety, offshore engineering construction, etc. The use of wave observations from satellite is an efficient way to correct model results. The goal of this paper is to assess the performance of assimilation in the MASNUM wave model for the Indian Ocean. The assimilation technique is based on Ensemble Adjusted Kalman Filter, with a variable ensemble constructed by the dynamic sampling method rather than ensemble members of wave model. Observations of significant wave height from satellites Jason-3 and CFOSAT are regarded as assimilation data and independent validation data, respectively. The results indicate good performance in terms of absolute mean error for significant wave height. Model error decreases by roughly 20–40% in high-sea conditions.


Author(s):  
Andreas Sterl ◽  
Sofia Caires

The European Centre for Medium Range Weather Forecasts (ECMWF) has recently finished ERA-40, a reanalysis covering the period September 1957 to August 2002. One of the products of ERA-40 consists of 6-hourly global fields of wave parameters like significant wave height and wave period. These data have been generated with the Centre’s WAM wave model. From these results the authors have derived climatologies of important wave parameters, including significant wave height, mean wave period, and extreme significant wave heights. Particular emphasis is on the variability of these parameters, both in space and time. Besides for scientists studying climate change, these results are also important for engineers who have to design maritime constructions. This paper describes the ERA-40 data and gives an overview of the results derived. The results are available on a global 1.5° × 1.5° grid. They are accessible from the web-based KNMI/ERA-40 Wave Atlas at http://www.knmi.nl/waveatlas.


2017 ◽  
Author(s):  
M. M. Amrutha ◽  
V. Sanil Kumar

Abstract. The growth and decay of surface wind-waves during one-month period in a typical Indian summer monsoon is investigated based on the data collected at 9 to 15 m water depth at 4 locations in the nearshore waters of the eastern Arabian Sea covering a spatial distance of ~ 350 km. The significant wave height varied from 0.7 to 5.5 m during the data collection considered in the analysis. The heights of waves during the measurement period often exceed 3 m. The most extreme wave height is 1.50 to 1.62 times the significant wave height and the most extreme crest height of the wave is 1.23 to 1.35 times the significant wave height of the same 30-minutes record. The average ratio of crest height of the wave to the height of the same wave is 0.58 to 0.67. The height of waves having maximum crest height is smaller than the maximum wave height during 30 minutes period. Measured waves are predominantly swell, but since the majority of wave generation during the monsoon is adjacent to the study area and the wind–wave coupling is strong, wave periods are rarely above 15 s. The numerical wave model could estimate the wave height reasonably well during the wave growth compared to the wave decay period. Hovmöller diagrams show a considerable spatial variability in the wave and wind pattern in the Indian Ocean during the high wave event at the eastern Arabian Sea.


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