Maximum entropy modelling of extreme significant wave heights on the Portuguese coast

2012 ◽  
pp. 511-518 ◽  
Keyword(s):  
Maximum Entropy ◽  
Significant Wave ◽  
Portuguese Coast ◽  
Wave Heights ◽  
Maximum Entropy Modelling ◽  
Significant Wave Heights

Prediction of extreme significant wave heights using maximum entropy

2013 ◽  
Vol 74 ◽  
pp. 1-10 ◽  
Author(s):  
V. Petrov ◽  
C. Guedes Soares ◽  
H. Gotovac
Keyword(s):  
Maximum Entropy ◽  
Significant Wave ◽  
Wave Heights ◽  
Significant Wave Heights

Return Value Estimation of Significant Wave Heights With Maximum Entropy Distribution

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
S. Dong ◽  
W. Liu ◽  
L. Z. Zhang ◽  
C. Guedes Soares
Keyword(s):  
Maximum Entropy ◽  
North Sea ◽  
Significant Wave ◽  
The North ◽  
Compound Distribution ◽  
Wave Heights ◽  
The North Sea ◽  
Significant Wave Heights ◽  
Maximum Entropy Distribution ◽  
Return Value

The maximum entropy distribution is proposed to fit the long term and extreme distribution of significant wave heights from which return value estimates are derived. The maximum entropy distribution is applied to data from two sites of different characteristics, namely from Japan characterized by the occurrence of typhoons and from the North Sea with continuous variation of sea state intensity. The compound distribution, Poisson-maximum entropy distribution, is described and adopted to model the data from these two locations. It is shown that in the case of continuous data from the North Sea, this model does not bring any advantage over the direct application of the maximum entropy distribution to adjust the significant wave heights larger than different thresholds. For this case the maximum entropy distribution provides good fits.

scholarly journals Numerical Analysis of the Effect of Binary Typhoons on Ocean Surface Waves in Waters Surrounding Taiwan

2021 ◽  
Vol 8 ◽  
Author(s):  
Tzu-Yin Chang ◽  
Hongey Chen ◽  
Shih-Chun Hsiao ◽  
Han-Lun Wu ◽  
Wei-Bo Chen
Keyword(s):  
Surface Waves ◽  
Ocean Surface ◽  
Separation Distance ◽  
Ocean Surface Waves ◽  
Significant Wave ◽  
Storm Wave ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
The One ◽  
Along Track

The ocean surface waves during Super Typhoons Maria (2018), Lekima (2019), and Meranti (2016) were reproduced using hybrid typhoon winds and a fully coupled wave-tide-circulation modeling system (SCHISM-WWM-III). The hindcasted significant wave heights are in good agreement with the along-track significant wave heights measured by the altimeters aboard the SARAL (Satellite with ARgos and ALtiKa) and Jason-2 satellites. Two numerical experiments pairing Super Typhoons Maria (2018) and Meranti (2016) and Super Typhoons Lekima (2019) and Meranti (2016) were conducted to analyze the storm wave characteristics of binary and individual typhoons. Four points located near the tracks of the three super typhoons were selected to elucidate the effects of binary typhoons on ocean surface waves. The comparisons indicate that binary typhoons not only cause an increase in the significant wave height simulations at four selected pints but also result in increases in the one-dimensional wave energy and two-dimensional directional wave spectra. Our results also reveal that the effects of binary typhoons on ocean surface waves are more significant at the periphery of the typhoon than near the center of the typhoon. The interactions between waves generated by Super Typhoons Maria (2018) and Meranti (2016) or Super Typhoons Lekima (2019) and Meranti (2016) might be diminished by Taiwan Island even if the separation distance between two typhoons is <700 km.

scholarly journals HYDRODYNAMIC AND BOUSSINESQ WAVE MODELING FOR THE N219 AMPHIBIOUS AIRCRAFT SEAPLANE DOCK DEVELOPMENT PLAN IN PANJANG ISLAND

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Hanah Khoirunnisa ◽  
Mardi Wibowo ◽  
Wahyu Hendriyono ◽  
Khusnul Setia Wardani
Keyword(s):  
Flight Test ◽  
The Other ◽  
Waveform Modeling ◽  
Significant Wave ◽  
Other Hand ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Wave Conditions ◽  
The Difference ◽  
Mike 21

The flight test of N219 Amphibious aircraft will be targeted in 2003/2024. For flight tests, these aircraft need a seaplane dock. One of the potential locations for the seaplane dock is Panjang Island at Seribu Islands. This study aims to know the characteristic of hydrodynamic and wave conditions and to determine whether Panjang Island is suitable for the seaplane dock. This study uses a modeling method with MIKE 21 FM HD-SW module and MIKE 21 Boussinesq Wave (BW)  module. The bathymetry data were obtained from the Indonesian Navy Hydrographic and Oceanographic Center (Pushidrosal), tide data is generated from Tide Model Driver (TMD), wave and wind data from ECMWF. The result of surface elevation validation between hydrodynamic modeling and TMD is 92%. During the west monsoon and spring conditions, the difference in the largest and lowest current velocity is quite large (0.018-0.199 m/s), on the other hand, when the tides are in neap conditions (0.008-0.144 m/s). Meanwhile, during the east monsoon and spring conditions, the difference in the largest and lowest current velocities is quite large (0.02-0.193 m/s), on the other hand, when the tides are in neap conditions (0.008-0.146 m/s). The maximum wave height resulting from the 50-year return period waveform modeling between 1.139 - 1.474 m. Meanwhile, the significant wave heights between 0.679 - 0.741 with a significant wave period of 13.45 seconds. In general, the current and wave conditions of the two locations are suitable for the construction of the seaplane dock, except that the dominant wave heights are still above the requirements.

Wave climate change in the Gulf of Bothnia

2021 ◽  
Author(s):  
Jan-Victor Björkqvist ◽  
Jani Särkkä ◽  
Hedi Kanarik ◽  
Laura Tuomi
Keyword(s):  
Climate Change ◽  
Wave Model ◽  
Wave Climate ◽  
Atmospheric Forcing ◽  
Simulation Data ◽  
Significant Wave ◽  
Gulf Of Bothnia ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Projected Changes

<p>Wave climate change in the Gulf of Bothnia in 2030–2059 was investigated using regional wave climate projections. For the simulations we used wave model WAM. As the atmospheric forcing for the wave model we had three global climate scenarios (HADGEM2-ES, MPI-ESM, EC-EARTH) downscaled with RCA4-NEMO regional model. The ice concentration for the wave model was obtained from NEMO ocean model simulations using the same atmospheric forcing. We used both RCP4.5 and RCP8.5 greenhouse gas scenarios. The spatial resolution of the simulation data was 1.8 km, enabling detailed analyses of the wave properties near the coast. From the simulation data we calculated statistics and return levels of significant wave heights using extreme value analysis, and assessed the projected changes in the wave climate in the Gulf of Bothnia. The projected increase in the significant wave heights is mainly due to the decreasing ice cover, especially in the Bothnian Bay. Projected changes in the most prevalent wind direction impacts the spatial pattern of the wave heights in the Bothnian Sea.</p>

scholarly journals Spatial Variation in Coastal Dune Evolution in a High Tidal Range Environment

2020 ◽  
Vol 12 (22) ◽  
pp. 3689
Author(s):  
Iain Fairley ◽  
Jose Horrillo-Caraballo ◽  
Ian Masters ◽  
Harshinie Karunarathna ◽  
Dominic E. Reeve
Keyword(s):  
Spatial Scales ◽  
Coastal Dunes ◽  
Sediment Supply ◽  
Tidal Range ◽  
Coastal Protection ◽  
Dune System ◽  
Pressure Transducers ◽  
Significant Wave ◽  
Wave Heights ◽  
Significant Wave Heights

Coastal dunes have global importance as ecological habitats, recreational areas, and vital natural coastal protection. Dunes evolve due to variations in the supply and removal of sediment via both wind and waves, and on stabilization through vegetation colonization and growth. One aspect of dune evolution that is poorly understood is the longshore variation in dune response to morphodynamic forcing, which can occur over small spatial scales. In this paper, a fixed wing unmanned aerial vehicle (UAV), is used to measure the longshore variation in evolution of a dune system in a megatidal environment. Dune sections to the east and west of the study site are prograding whereas the central portion is static or eroding. The measured variation in dune response is compared to mesoscale intertidal bar migration and short-term measurements of longshore variation in wave characteristics during two storms. Intertidal sand bar migration is measured using satellite imagery: crescentic intertidal bars are present in front of the accreting portion of the beach to the west and migrate onshore at a rate of 0.1–0.2 m/day; episodically the eastern end of the bar detaches from the main bar and migrates eastward to attach near the eastern end of the study area; bypassing the central eroding section. Statistically significant longshore variation in intertidal wave heights were measured using beachface mounted pressure transducers: the largest significant wave heights are found in front of the dune section suffering erosion. Spectral differences were noted with more narrow-banded spectra in this area but differences are not statistically significant. These observations demonstrate the importance of three-dimensionality in intertidal beach morphology on longshore variation in dune evolution; both through longshore variation in onshore sediment supply and through causing longshore variation in near-dune significant wave heights.

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