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Pierre Larouche and Claude Cariou

synthetic aperture radar (SAR) image of a wave field penetrating a marginal ice zone offNewfoundlandwas analyzed in order to get ins'tght into the physical processes responsible for the swell attenuation. The analysiswas done using a parametric speetral-density estimation technique based on linear prediction. This approachallows the estimation of the directional spectrum of the swell on small images with a better low-frequencydefinition than nonparametric spectral estimation methods like fast Fourier

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A. D. Heathershaw, J. Small, and C. E. Stretch

energctics and spectra of the simulatedenvironments have confirmed the effect ofbiharmonic friction in suppressing small-scale motion while maintainingthe mesoscale. However, a new result concerns the impact of this scale selectivity on simulated underwateracoustic fields and the possible consequences of this for ocean forecast models and acoustic tomography applications. Acoustic effects have been quantified in terms of the differences in predicted sound intensity levels betweenharmonic and

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Kunio Rikiishi

set to be approximately 10 or 12 m s-~at the pitot tube station.3. Simultaneous determination of the directional spectrum and phase velocity So far, three techniques have been used to determine the phase velocity of wind waves. The first one,used by Hamada et al. (1953) and Plate and Trawle(1970), determines the phase velocity of individualwave by measuring the time required for each wavecrest to pass through a given distance. The technique of Hidy and Plate (1966) using succesiveframes of a

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Fabrice Veron, W. Kendall Melville, and Luc Lenain

). Thus the waves are central to improved models of momentum transfer between the atmosphere and the ocean. In the late 1990s, following extensive study of the significance of the waves on the drag coefficient, the European Centre for Medium-Range Weather Forecasts (ECMWF) included wave effects in its parameterization of the air–sea drag coefficient in its coupled general circulation modeling. With the recent interest in air–sea heat fluxes and satellite sea surface temperature (SST) measurements in

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A. M. Moore, N. S. Cooper, and D. L. T. Anderson

years. Such climate forecasts arc likelyto be made using coupled general circulation models(CGCM), composed of an atmospheric componentsimilar to existing atmospheric general circulationmodels (AGCMs) and an ocean component similar toexisting ocean GCMs. Before a climate forecast can be made, both oceanicand atmospheric components of the coupled modelmust be initialized. Meteorologists have developed dataassimilation and initialization schemes that arc usedoperationally (scc, for instance, the

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Fabrice Ardhuin, T. H. C. Herbers, Kristen P. Watts, Gerbrant Ph van Vledder, R. Jensen, and Hans C. Graber

1. Introduction Wave forecasting and hindcasting is based on a large body of theory (e.g., Komen et al. 1994 ; Janssen 2004 ), which is often insufficient to fully account for complex flows near the ocean surface. For engineering purposes and to provide a benchmark for modeling wave growth, many studies have used dimensional analysis following Kitaigorodskii (1962) and established empirical relations between the wave spectrum and the fetch or duration of wind forcing, water depth, and wind

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W. G. Large, J. Morzel, and G. B. Crawford

between wind stresses inferred from observed profiles and coincident stresses obtained fromthe eddy correlation technique (Dittmer 1977). Thec 1995 American Meteorological Society2960 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME25wind-wave tank results of Tseng et al. (1992) can beinterpreted in a similar fashion, even though they formulate the problem in terms of the height of

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Andrew M. Moore

One of the main objectives of the Tropical OceanGlobal Atmosphere program (TOGA) is to develop aclimate forecasting capability for timescales rangingfrom a few months to a few years, so that we can eventually predict, with certainty, approaching climateanomalies such as E1 Nifio. To achieve this objective,there is an urgent need to develop effective four-dimensional data assimilation schemes for tropical oceanmodels which will ultimately be incorporated into theCoupled atmosphere

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J. H. Lee, J. P. Monty, J. Elsnab, A. Toffoli, A. V. Babanin, and A. Alberello

flows require further investigation to improve predictions of dissipation in breaking waves. Whitecapping (breaking) dissipation is one of the three major source terms for wave-forecast models, but it is very difficult to measure because of the sporadic nature of the wave-breaking events. To estimate the total dissipation, the volumetric dissipation rate through the water column is required and then integrated. However, the profile of the volumetric dissipation rate diverges near the surface, and

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Andrew M. Moore

models in a predictive mode,they must be initialized using data assimilation techniques, and whatever observational data is available.When it comes to selecting observational data formodel initialization, oceanographers cannot afford tobe as selective as meteorologists about what observations they use, and they must try to use whatever information is at hand. The approach of oceanographersto data assimilation is therefore somewhat differentfrom that of meteorologists. Many investigators have

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