scholarly journals WIND SPECIFICATION FOR SPECTRAL OCEAN-WAVE MODELS

1986 ◽  
Vol 1 (20) ◽  
pp. 28
Author(s):  
M.L. Khandekar ◽  
B.M. Eid
Keyword(s):  
Weather Prediction ◽  
Wave Model ◽  
Numerical Weather Prediction Model ◽  
Ocean Wave ◽  
Operational Mode ◽  
Spectral Models ◽  
Ocean Wave Model ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Wave Models

This paper investigates the utility of winds obtainable from a numerical weather prediction model for driving a spectral ocean-wave model in an operational mode. Wind inputs for two operational spectral wave models were analyzed with respect to observed winds at three locations in the Canadian east coast offshore. Also, significant wave heights obtainable from the two spectral models were evaluated against measured wave data at these locations. Based on this analysis, the importance of appropriate wind specification for operational wave analysis and forecasting is demonstrated.

scholarly journals Evaluation of Global Wave Probabilities Consistent with Official Forecasts

2021 ◽  
Author(s):  
Charles R. Sampson ◽  
Efren A. Serra ◽  
John A. Knaff ◽  
Joshua H. Cossuth
Keyword(s):  
Tropical Cyclone ◽  
Weather Prediction ◽  
Forecast Accuracy ◽  
Numerical Weather Prediction Model ◽  
Lead Times ◽  
Significant Wave ◽  
Wave Heights ◽  
High Bias ◽  
Significant Wave Heights ◽  
The U.S

AbstractThe U.S. Navy is keenly interested in analyses and predictions of waves at sea due to their effects on important tasks such as shipping, base preparedness and disaster relief. U.S. Tropical Cyclone (TC) Forecast Centers routinely disseminate wind probabilities consistent with official TC forecasts worldwide, but do not do the same for wave forecasts. These probabilities are especially important at longer leads where TC forecast accuracy diminishes. This work describes global wave probabilities consistent with both the official TC forecasts and their wind probabilities. Real-time runs for 84 TCs between May 2018 and March 2019, with probabilities generated for 12-ft and 18-ft significant wave heights are used to calculate verification statistics. This results in 347, 319, 261, 214, 155, and 112 verification cases at lead times of 1, 2, 3, 4, and 5 days where each verification case consists of a 20x20 degree latitude longitude grid around the verifying TC position. When compared with wave probabilities generated solely by a global numerical weather prediction model, the wind probability-based algorithm demonstrates improved consistency with official forecasts and provides additional benefits. Those benefits include an improved capability to discriminate between 12-ft and 18-ft significant wave events and non-events. The verification statistics also shows that the wind probability-based algorithm has a consistent high bias. How these biases can be reduced in future efforts is also discussed.

scholarly journals Long and Short-Term Simulations of Seto Inland Sea by Coupled Ocean-Wave Model

2013 ◽  
Vol 69 (2) ◽  
pp. I_511-I_515
Author(s):  
Yusuke TANAKA ◽  
Nobuhito MORI ◽  
Junichi NINOMIYA ◽  
Koichi SUGIMATSU ◽  
Hiroshi YAGI ◽  
...  
Keyword(s):  
Wave Model ◽  
Ocean Wave ◽  
Seto Inland Sea ◽  
Short Term ◽  
Ocean Wave Model

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.

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>

TYPHOON EARLY WARNING SYSTEM BASED ON A COUPLED ATMOSPHERE-OCEAN-WAVE MODEL

2007 ◽  
Author(s):  
Jun Yoshino ◽  
Tomokazu Murakami ◽  
Masanori Hayashi ◽  
Takashi Yasuda
Keyword(s):  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Wave Model ◽  
Ocean Wave ◽  
Ocean Wave Model

scholarly journals Impact of the Reduced Drag Coefficient on Ocean Wave Modeling under Hurricane Conditions

2008 ◽  
Vol 136 (3) ◽  
pp. 1217-1223 ◽  
Author(s):  
Il-Ju Moon ◽  
Isaac Ginis ◽  
Tetsu Hara
Keyword(s):  
Drag Coefficient ◽  
Hurricane Katrina ◽  
Wind Wave ◽  
Wave Model ◽  
High Wind ◽  
Model Surface ◽  
Wind Speeds ◽  
Tank Experiment ◽  
Wave Heights ◽  
Significant Wave Heights

Abstract Effects of new drag coefficient (Cd) parameterizations on WAVEWATCH III (WW3) model surface wave simulations are investigated. The new parameterizations are based on a coupled wind–wave model (CWW) and a wave tank experiment, and yields reduced Cd at high wind speeds. Numerical experiments for uniform winds and Hurricane Katrina (2005) indicate that the original Cd parameterization used in WW3 overestimates drag at high wind speeds compared to recent observational, theoretical, and numerical modeling results. Comparisons with buoy measurements during Hurricane Katrina demonstrate that WW3 simulations with the new Cd parameterizations yield more accurate significant wave heights compared to simulations with the original Cd parameterization, provided that accurate high-resolution wind forcing fields are used.

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