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1.
One-dimensional theory of the wave boundary layer 总被引：2，自引：0，他引：2
Results obtained in a 2-D modeling of the statistical structure of the wave boundary layer (WBL) are used for elaboration of the general approach to 1-D modeling taking into account the spectral properties of wave drag for an arbitrary wave field. In the case of the wave field described by the JONSWAP spectrum, the momentum and energy spectral density exchange, vertical profiles of the wave-induced momentum flux and dependence of total roughness parameter and drag coefficient on peak frequency are given. The reasons that the total roughness parameter increases with decreasing fetch are explained. The role of wind waves as an active element of the ocean-atmosphere dynamic system is also discussed. 相似文献
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Models of the wave boundary layer 总被引：2，自引：1，他引：1
A general approach to model the structure of the wave boundary layer, based on the nonlinear Reynolds equations in a curvilinear system of coordinates, is described. Both spectral and numerical grid models are used. The energetic interactions between wind and wave in terms of Miles' parameter are studied. For waves outrunning or running against the wind, the range of the inverse flux of energy is found. For waves running slower than the wind, quadratic growth of is established. Vertical profiles of the wave momentum flux for different fetches are given. Following P. Janssen, a one-dimensional analytical model of the wave boundary layer is suggested. The effect of waves on the drag coefficient is analyzed. 相似文献
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PER MÖLLER DMITRY YU. BOLSHIYANOV HELENE BERGSTEN 《Boreas: An International Journal of Quaternary Research》1999,28(1):92-114
The Taymyr Peninsula constitutes the eastern delimitation of a possible Kara Sea basin ice sheet. The existence of such an ice sheet during the last global glacial maximum (LGM), i.e. during the Late Weichselian/Upper Zyryansk, is favoured by some Russian scientists. However, a growing number of studies point towards a more minimalistic view concerning the areal extent of Late Weichselian/Upper Zyryansk Siberian glaciation. Investigations carried out by us along the central Byrranga Mountains and in the Taymyr Lake basin south thereof, reject the possibility of a Late Weichselian/Upper Zyryansk glaciation of this area. Our conclusion is based on the following: Dating of a continuous lacustrine sediment sequence at Cape Sabler on the Taymyr Lake shows that it spans at least the period 39-17 ka BP. Even younger ages have been reported, suggesting that this lacustrine environment prevailed until shortly before the Holocene. The distribution of these sediments indicates the existence of a paleo-Taymyr lake reaching c. 60 m above present sea level. A reconnaissance of the central part of the Byrranga Mountains gave no evidence of any more recent glacial coverage. The only evidence of glaciation - an indirect one - is deltaic sequences around 100-120 m a.s.l., suggesting glacio-isostatic depression and a large input of glacial meltwater from the north. However, 14C and ESR datings of these marine sediments suggest that they are of Early Weichselian/Lower Zyryansk or older age. As they are not covered by till and show no glaciotectonic disturbances, they support our opinion that there was no Late Weichselian/Lower Zyryansk glaciation in this area. We thus suggest that the Taymyr Peninsula was most probably glaciated during the early part of the last glacial cycle (when there was only small- to medium-scale glaciation in Scandinavia), but not glaciated during the later part of that cycle (which had the maximum ice-sheet coverage over north-western Europe). This fits a climatic scenario suggesting that the Taymyr area, like most of Siberia, would come into precipitation shadow during times with large-scale ice-sheet coverage of Scandinavia and the rest of north-western Europe. 相似文献
4.
D. V. Chalikov 《Boundary-Layer Meteorology》1986,34(1-2):63-98
A new approach to investigations of the structure of the boundary layer above waves is discussed. The approach is based on direct numerical simulation of wave motions in the boundary layer produced by a moving curved surface. Model equations are derived, which are the Reynolds equations in a curvilinear nonstationary system of co-ordinates, evolution equations for turbulent kinetic energy, and Kolmogorov's approximate similarity formulae relating the coefficient of turbulent viscosity to the dissipation of turbulent energy; the length scale is assumed to grow linearly with increasing distance from the surface. Principles of constructing the model numerical scheme are described. Results are given of modelling the structure of the boundary layer above a nonsteady surface, which, in a general case, is a superposition of progressive waves with assigned dispersion relations and amplitudes. Mechanisms of energy and momentum transfer to the surface, effects of density stratification and energy structure in the boundary layer are studied. Merits and demerits of the approach are discussed. 相似文献
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We show that interaction of two monochromatic waves at the water surface enters a different dynamic regime if their wavenumbers become very close. The study is conducted by means of a fully nonlinear wave model. In the course of evolution of the two waves, downshifting of the initial wave energy and growth of the first mode occur depending on wave steepness and dk/k. Behaviour of these features changes if dk/k?<?0.0025: both downshifting and growth rate become independent of dk/k, accompanied by rapid transfer of wave energy to large scales. 相似文献
7.
A simple and exact numerical scheme for long-term simulations of 3D potential fully nonlinear periodic gravity waves is suggested. The scheme is based on the surface-following nonorthogonal curvilinear coordinate system. Velocity potential is represented as a sum of analytical and nonlinear components. The Poisson equation for the nonlinear component of velocity potential is solved iteratively. Fourier transform method, the second-order accuracy approximation of vertical derivatives on a stretched vertical grid and the fourth-order Runge–Kutta time stepping are used. The scheme is validated by simulation of steep Stokes waves. A one-processor version of the model for PC allows us to simulate evolution of a wave field with thousands degrees of freedom for hundreds of wave periods. The scheme is designed for investigation of nonlinear 2D surface waves, generation of extreme waves, and direct calculations of nonlinear interactions. 相似文献
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Ocean Dynamics - A Correction to this paper has been published: https://doi.org/ https://doi.org/10.1007/s10236-021-01450-3 相似文献
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ELISABETH ISAKSSON DMITRY DIVINE JACK KOHLER TONU MARTMA VEIJO POHJOLA HIDEAKI MOTOYAMA OKITSUGU WATANABE 《Geografiska Annaler: Series A, Physical Geography》2005,87(1):203-214
ABSTRACT. We apply two different time series analytical tools to ω18 O records from two Svalbard ice cores. One ice core is from Lomonosovfonna at 1250 ma.s.l. and the other from Austfonna at 750 m a.s.l. These cores are estimated to cover at least the past 800 years and have been dated using a combination of known reference horizons and glacial modelling. Wavelet analysis reveals low frequency oscillations on the 60–120–year scale on the lower elevation site Austfonna while the higher altitude site on Lomonosovfonna does not reveal such variability throughout the record. The second method, Significant Zero Crossing of Derivates (SiZer) does not resolve the low-frequency periodicity seen in the wavelet analysis. The low-frequency variability resolved by the wavelet analysis is similar to what has been found in various climate records including instrumental temperatures and tree-rings, and has been proposed as the most important oscillation for the observed trends in Arctic air temperatures. 相似文献