scholarly journals ASSESSING THE ACCURACY OF SHALLOW WATER DEPTH ESTIMATION BY USING MULTISPECTRAL SATELLITE IMAGES

2021 ◽  
pp. 180-197
Author(s):  
Ratna Sari DEWI ◽  
Aldino RIZALDY ◽  
Prayudha HARTANTO ◽  
Suprajaka SUPRAJAKA
2015 ◽  
Vol 69 (1) ◽  
pp. 113-126 ◽  
Author(s):  
Xiaolin Bian ◽  
Yun Shao ◽  
Wei Tian ◽  
Chunyan Zhang

This paper presents a shallow water depth estimation methodology using S-band Synthetic Aperture Radar (SAR) data from the HJ-1C satellite. It is based on the shoaling and refraction of long surface gravity waves as they propagate shoreward. A two-scale Bragg scattering model is used to describe the imaging process of long waves by SAR. By computing the Fast Fourier Transformation (FFT) for the selected sub image, wavelength and direction of the long wave can be retrieved from the two-dimensional (2D) spectra with wave tracking technology. Shallow water depths are then obtained from the linear dispersion relation with the calculated angular wave frequency obtained from other sources or first guesses of initial water depths or wave periods. Applicability and effectiveness are tested in the near-shore area of the Fujian province, China. Comparison between the derived results and water depths from an Electronic Navigational Chart (ENC) indicates that HJ-1C SAR is capable of higher resolution underwater topography detection, and the methodology can be used for shallow water depth estimation with good accuracy. The average absolute error and average relative error of the estimated results is 0·86 m and 11·05%, respectively.


2009 ◽  
Vol 30 (23) ◽  
pp. 6241-6260 ◽  
Author(s):  
Hung-Ming Kao ◽  
Hsuan Ren ◽  
Chao-Shing Lee ◽  
Chung-Pa Chang ◽  
Jiun-Yee Yen ◽  
...  

2011 ◽  
Vol 2 (2) ◽  
pp. 320-333
Author(s):  
F. Van den Abeele ◽  
J. Vande Voorde

The worldwide demand for energy, and in particular fossil fuels, keeps pushing the boundaries of offshoreengineering. Oil and gas majors are conducting their exploration and production activities in remotelocations and water depths exceeding 3000 meters. Such challenging conditions call for enhancedengineering techniques to cope with the risks of collapse, fatigue and pressure containment.On the other hand, offshore structures in shallow water depth (up to 100 meter) require a different anddedicated approach. Such structures are less prone to unstable collapse, but are often subjected to higherflow velocities, induced by both tides and waves. In this paper, numerical tools and utilities to study thestability of offshore structures in shallow water depth are reviewed, and three case studies are provided.First, the Coupled Eulerian Lagrangian (CEL) approach is demonstrated to combine the effects of fluid flowon the structural response of offshore structures. This approach is used to predict fluid flow aroundsubmersible platforms and jack-up rigs.Then, a Computational Fluid Dynamics (CFD) analysis is performed to calculate the turbulent Von Karmanstreet in the wake of subsea structures. At higher Reynolds numbers, this turbulent flow can give rise tovortex shedding and hence cyclic loading. Fluid structure interaction is applied to investigate the dynamicsof submarine risers, and evaluate the susceptibility of vortex induced vibrations.As a third case study, a hydrodynamic analysis is conducted to assess the combined effects of steadycurrent and oscillatory wave-induced flow on submerged structures. At the end of this paper, such ananalysis is performed to calculate drag, lift and inertia forces on partially buried subsea pipelines.


2010 ◽  
Vol 49 (36) ◽  
pp. 6995 ◽  
Author(s):  
Steven Mitchell ◽  
Jeffrey P. Thayer ◽  
Matthew Hayman

2013 ◽  
Vol 36 (4) ◽  
pp. 365-376 ◽  
Author(s):  
Ariyo Kanno ◽  
Yoji Tanaka ◽  
Akira Kurosawa ◽  
Masahiko Sekine

Author(s):  
Yen Phan Quoc

Remote sensing technology has an important role to provide information for the establishment of habitat and bathymetry maps in shallow water areas. However, sun glint on the water surface has changed spectral reflectance in body water recorded by the sensor, thus seriously distorting water column and benthic properties. So, the sun glint should be removed prior to image analysis to improve the accuracy. This study aims to remove the sun glint from Sentinel-2 multi-spectral satellite images by two common methods of Lyzenga and Hedley for shallow waters in the surrounding areas of the Spratly islands archipelago. The experimental results were evaluated by spectrographic comparison after calibration by the two methods. In addition, the efficiency of the two methods was clearly shown in the application of depth estimation using the Lyzenga method for image data at two points. The result increases the R2 correlation coefficient and decreases the root-mean-square RMSE of the model estimate of the significant amount of depth after calibration.


Author(s):  
F F Puristiawan ◽  
R Maftukhah ◽  
D R Ningrum ◽  
B D A Nugroho

Author(s):  
Jiasheng XU ◽  
Guoqing ZHOU ◽  
Qiaobo Cao ◽  
Sikai SU ◽  
Zhou Tian ◽  
...  

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