Analysis and Interpretation of Frequency–Wavenumber Spectra of Young Wind Waves
| Autor: | Fabrice Ardhuin, Fabien Leckler, Alvise Benetazzo, Filippo Bergamasco, Charles Peureux, V. A. Dulov |
|---|---|
| Přispěvatelé: | Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Istituto di Scienze Marine [Venezia] (ISMAR-CNR), Istituto di Science Marine (ISMAR ), Consiglio Nazionale delle Ricerche (CNR)-Consiglio Nazionale delle Ricerche (CNR), University of Ca’ Foscari [Venice, Italy], Marine Hydrophysical Institute (MHI), National Academy of Sciences of Ukraine (NASU) |
| Rok vydání: | 2015 |
| Předmět: |
Infragravity wave
Settore GEO/12 - Oceanografia e Fisica dell'Atmosfera Seismic noise Oceanography Circulation/Dynamics Optics Observational techniques and algorithms Oceanic Remote sensing Waves Wind wave Circulation/ Dynamics Wavenumber 14. Life underwater Gravity wave [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Physics Settore INF/01 - Informatica business.industry Swell Dynamics Computational physics Circulation Wavelength Mechanical wave business oceanic |
| Zdroj: | Journal of Physical Oceanography Journal of Physical Oceanography, American Meteorological Society, 2015, 45 (10), pp.2484-2496. ⟨10.1175/JPO-D-14-0237.1⟩ Journal Of Physical Oceanography (0022-3670) (Amer Meteorological Soc), 2015-10, Vol. 45, N. 10, P. 2484-2496 Journal of physical oceanography 45 (2015): 2484–2496. doi:10.1175/JPO-D-14-0237.1 info:cnr-pdr/source/autori:Leckler, Fabien; Ardhuin, Fabrice; Peureux, Charles; Benetazzo, Alvise; Bergamasco, Filippo; Dulov, Vladimir/titolo:Analysis and Interpretation of Frequency-Wavenumber Spectra of Young Wind Waves/doi:10.1175%2FJPO-D-14-0237.1/rivista:Journal of physical oceanography/anno:2015/pagina_da:2484/pagina_a:2496/intervallo_pagine:2484–2496/volume:45 |
| ISSN: | 1520-0485 0022-3670 |
| Popis: | The energy level and its directional distribution are key observations for understanding the energy balance in the wind-wave spectrum between wind-wave generation, nonlinear interactions, and dissipation. Here, properties of gravity waves are investigated from a fixed platform in the Black Sea, equipped with a stereo video system that resolves waves with frequency f up to 1.4 Hz and wavelengths from 0.6 to 11 m. One representative record is analyzed, corresponding to young wind waves with a peak frequency fp = 0.33 Hz and a wind speed of 13 m s−1. These measurements allow for a separation of the linear waves from the bound second-order harmonics. These harmonics are negligible for frequencies f up to 3 times fp but account for most of the energy at higher frequencies. The full spectrum is well described by a combination of linear components and the second-order spectrum. In the range 2fp to 4fp, the full frequency spectrum decays like f−5, which means a steeper decay of the linear spectrum. The directional spectrum exhibits a very pronounced bimodal distribution, with two peaks on either side of the wind direction, separated by 150° at 4fp. This large separation is associated with a significant amount of energy traveling in opposite directions and thus sources of underwater acoustic and seismic noise. The magnitude of these sources can be quantified by the overlap integral I(f), which is found to increase sharply from less than 0.01 at f = 2fp to 0.11 at f = 4fp and possibly up to 0.2 at f = 5fp, close to the 0.5π value proposed in previous studies. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|