Evolution of Directional Wave Spectra in the Marginal Ice Zone: A New Model Tested with Legacy Data

2016 ◽  
Vol 46 (10) ◽  
pp. 3121-3137 ◽  
Author(s):  
Vernon A. Squire ◽  
Fabien Montiel

AbstractField experimental data from a 1980s program in the Greenland Sea investigating the evolution of directional wave spectra in the marginal ice zone are reanalyzed and compared with the predictions of a new, phase-resolving, three-dimensional model describing the two-dimensional scattering of the waves by the vast number of ice floes that are normally present. The model is augmented with a dissipative term to account for the nonconservative processes affecting wave propagation. Observations reported in the experimental study are used to reproduce the ice conditions and wave forcing during the experiments. It is found that scattering alone underestimates the attenuation experienced by the waves during their passage through the ice field. With dissipation, however, the model can replicate the observed attenuation for most frequencies in the swell regime. Model predictions and observations of directional spreading are in agreement for short to midrange wave periods, where the wave field quickly becomes isotropic. For larger wave periods, little spreading can be seen in the model predictions, in contrast to the isotropic or near-isotropic seas reported in the experimental study. The discrepancy is conjectured to be a consequence of the inaccurate characterization of the ice conditions in the model and experimental errors.

2010 ◽  
Vol 662 ◽  
pp. 1-4 ◽  
Author(s):  
C. M. LINTON

Over the past forty or so years, considerable advances have been made in our understanding of the effects of ocean waves on sea ice, and vice versa, with observations, experiments and theory all playing their part. Recent years have seen the development of ever more sophisticated mathematical models designed to represent the physics more accurately and incorporate new features. What is lacking is an approach to three-dimensional scattering for ice floes that is both accurate and efficient enough to be used as a component in a theory designed to model the passage of directional wave spectra through the marginal ice zone. Bennetts & Williams (J. Fluid Mech., 2010, this issue, vol. 662, pp. 5–35) have brought together a number of solution techniques honed on simpler problems to provide just such a component.


Author(s):  
Zahra Ranji ◽  
Mohsen Soltanpour ◽  
Tomoya Shibayama

Extensive field measurements along the north coast of the Gulf of Oman are analyzed to study the spectral characteristics of the generated waves of Ashobaa along the path of cyclone. The data showed a maximum significant wave height of about 3.2 meters on Iranian coasts. MLMST algorithm was used to process the directional wave. The measured wave spectra were bimodal (or trimodal) when the cyclone was far from the measuring stations. Approaching closer to the stations, the waves turned to unimodal spectra, with the highest measured wave energies at the time of minimum distance between the cyclone eye and the stations. Wave spectrum became bimodal again at the time of landfall, including the local seas and swell waves of the cyclone. After dissipation of the cyclone, swell waves dominate resulting in unimodal wave spectra. Study of 2D wave spectra reveals that minimum values of directional spreading correspond to peak frequencies.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/k9Bs4TebgdE


2021 ◽  
Vol 230 ◽  
pp. 109057
Author(s):  
Mohammad Adibzade ◽  
Mehdi Shafieefar ◽  
Hassan Akbari ◽  
Roozbeh Panahi

2010 ◽  
Vol 40 (1) ◽  
pp. 155-169 ◽  
Author(s):  
Heidi Pettersson ◽  
Kimmo K. Kahma ◽  
Laura Tuomi

Abstract In slanting fetch conditions the direction of actively growing waves is strongly controlled by the fetch geometry. The effect was found to be pronounced in the long and narrow Gulf of Finland in the Baltic Sea, where it significantly modifies the directional wave climate. Three models with different assumptions on the directional coupling between the wave components were used to analyze the physics responsible for the directional behavior of the waves in the gulf. The directionally decoupled model produced the direction at the spectral peak correctly when the slanting fetch geometry was narrow but gave a weaker steering than observed when the fetch geometry was broader. The method of Donelan estimated well the direction at the spectral peak in well-defined slanting fetch conditions, but overestimated the longer fetch components during wave growth from a more complex shoreline. Neither the decoupled nor the Donelan model reproduced the observed shifting of direction with the frequency. The performance of the third-generation spectral wave model (WAM) in estimating the wave directions was strongly dependent on the grid resolution of the model. The dominant wave directions were estimated satisfactorily when the grid-step size was dropped to 5 km in the gulf, which is 70 km in its narrowest part. A mechanism based on the weakly nonlinear interactions is proposed to explain the strong steering effect in slanting fetch conditions.


1992 ◽  
Vol 114 (3) ◽  
pp. 727-734 ◽  
Author(s):  
W. C. Lee ◽  
O. A. Plumb ◽  
L. Gong

An experimental study has been conducted to provide a data base for drying packed beds of granular, nonhygroscopic materials. Experimental results for drying rate, saturation distribution, temperature distribution, and surface saturation are reported for drying glass beads under carefully documented drying conditions. Capillary pressure for both imbibition and drainage was measured for the glass beads, whose size ranged from 65 μm to 450 μm. The drying results demonstrate that, contrary to available model predictions, porous materials do not necessarily exhibit saturation gradients that always increase with distance from the drying surface. Under certain conditions the capillary potential is sufficient to create an internal drying front. The measurements of surface saturation are the first to be reported. They are utilized to speculate on the reasons for the failure of drying models to compare well with experiment without adjusting the convective heat or mass transfer coefficients.


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