A layered numerical model for simulating the generation and propagation of internal tides over continental slope III. Numerical experiments and simulation

2000 ◽  
Vol 18 (1) ◽  
pp. 18-24
Author(s):  
Du Tao ◽  
Fang Xin-hua ◽  
Fang Guo-hong
Keyword(s):  
Numerical Model ◽  
Continental Slope ◽  
Numerical Experiments ◽  
Internal Tides

Axisymmetric Hurricane in a Dry Atmosphere: Theoretical Framework and Numerical Experiments

2011 ◽  
Vol 68 (8) ◽  
pp. 1607-1619 ◽  
Author(s):  
Agnieszka A. Mrowiec ◽  
Stephen T. Garner ◽  
Olivier M. Pauluis
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Numerical Model ◽  
Numerical Experiments ◽  
Momentum Flux ◽  
Theoretical Framework ◽  
Moist Processes ◽  
Energy And Momentum ◽  
The Relationship ◽  
Theoretical Insight

Abstract This paper discusses the possible existence of hurricanes in an atmosphere without water vapor and analyzes the dynamic and thermodynamic structures of simulated hurricane-like storms in moist and dry environments. It is first shown that the “potential intensity” theory for axisymmetric hurricanes is directly applicable to the maintenance of a balanced vortex sustained by a combination of surface energy and momentum flux, even in the absence of water vapor. This theoretical insight is confirmed by simulations with a high-resolution numerical model. The same model is then used to compare dry and moist hurricanes. While it is found that both types of storms exhibit many similarities and fit well within the theoretical framework, there are several differences, most notably in the storm inflow and in the relationship between hurricane size and intensity. Such differences indicate that while water vapor is not necessary for the maintenance of hurricane-like vortices, moist processes directly affect the structure of these storms.

scholarly journals Impact of Channel Geometry and Rotation on the Trapping of Internal Tides

2007 ◽  
Vol 37 (11) ◽  
pp. 2740-2763 ◽  
Author(s):  
Sybren Drijfhout ◽  
Leo R. M. Maas
Keyword(s):  
Continental Slope ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Ocean Model ◽  
Internal Tides ◽  
Open Boundary ◽  
Kelvin Wave ◽  
Channel Geometry ◽  
Channel Slope ◽  
The Cross

Abstract The generation and propagation of internal tides has been studied with an isopycnic three-dimensional ocean model. The response of a uniformly stratified sea in a channel, which is forced by a barotropic tide on its open boundary, is considered. The tide progresses into the channel and forces internal tides over a continental slope at the other end. The channel has a length of 1200 km and a width of 191.25 km. The bottom profile has been varied. In a series of four experiments it is shown how the cross-channel geometry affects the propagation and trapping of internal tides, and the penetration scale of wave energy, away from the continental slope, is discussed. In particular it is found that a cross-channel bottom slope constrains the penetration of the internal tidal energy. Most internal waves refract toward a cross-channel plane where they are trapped. The exception is formed by edge waves that carry part of the energy away from the continental slope. In the case of rotation near the continental slope, the Poincaré waves that arise in the absence of a cross-channel slope no longer bear the characteristics of the wave attractor predicted by 2D theory, but are almost completely arrested, while the right-bound Kelvin wave preserves the 2D attractor in the cross-channel plane, which is present in the nonrotating case. The reflected, barotropic right-bound Kelvin wave acts as a secondary internal wave generator along the cross-channel slope.

Internal Tides and Turbulence along the 3000-m Isobath of the Hawaiian Ridge

2006 ◽  
Vol 36 (6) ◽  
pp. 1165-1183 ◽  
Author(s):  
Craig M. Lee ◽  
Thomas B. Sanford ◽  
Eric Kunze ◽  
Jonathan D. Nash ◽  
Mark A. Merrifield ◽  
...  
Keyword(s):  
Numerical Model ◽  
Dissipation Rate ◽  
Internal Tide ◽  
Internal Tides ◽  
Energy Fluxes ◽  
Density Profiles ◽  
Turbulent Dissipation ◽  
Model Average ◽  
Diapycnal Diffusivity ◽  
Hawaiian Ridge

Abstract Full-depth velocity and density profiles taken along the 3000-m isobath characterize the semidiurnal internal tide and bottom-intensified turbulence along the Hawaiian Ridge. Observations reveal baroclinic energy fluxes of 21 ± 5 kW m−1 radiating from French Frigate Shoals, 17 ± 2.5 kW m−1 from Kauai Channel west of Oahu, and 13 ± 3.5 kW m−1 from west of Nihoa Island. Weaker fluxes of 1–4 ± 2 kW m−1 radiate from the region near Necker Island and east of Nihoa Island. Observed off-ridge energy fluxes generally agree to within a factor of 2 with those produced by a tidally forced numerical model. Average turbulent diapycnal diffusivity K is (0.5–1) × 10−4 m2 s–1 above 2000 m, increasing exponentially to 20 × 10−4 m2 s–1 near the bottom. Microstructure values agree well with those inferred from a finescale internal wave-based parameterization. A linear relationship between the vertically integrated energy flux and vertically integrated turbulent dissipation rate implies that dissipative length scales for the radiating internal tide exceed 1000 km.

scholarly journals Speed and Evolution of Nonlinear Internal Waves Transiting the South China Sea

2010 ◽  
Vol 40 (6) ◽  
pp. 1338-1355 ◽  
Author(s):  
Matthew H. Alford ◽  
Ren-Chieh Lien ◽  
Harper Simmons ◽  
Jody Klymak ◽  
Steve Ramp ◽  
...  
Keyword(s):  
South China Sea ◽  
Continental Slope ◽  
Internal Waves ◽  
South China ◽  
The South China Sea ◽  
Internal Tides ◽  
Deep Basin ◽  
Nonlinear Internal Waves ◽  
The Waves ◽  
Upper Slope

Abstract In the South China Sea (SCS), 14 nonlinear internal waves are detected as they transit a synchronous array of 10 moorings spanning the waves’ generation site at Luzon Strait, through the deep basin, and onto the upper continental slope 560 km to the west. Their arrival time, speed, width, energy, amplitude, and number of trailing waves are monitored. Waves occur twice daily in a particular pattern where larger, narrower “A” waves alternate with wider, smaller “B” waves. Waves begin as broad internal tides close to Luzon Strait’s two ridges, steepening to O(3–10 km) wide in the deep basin and O(200–300 m) on the upper slope. Nearly all waves eventually develop wave trains, with larger–steeper waves developing them earlier and in greater numbers. The B waves in the deep basin begin at a mean speed of ≈5% greater than the linear mode-1 phase speed for semidiurnal internal waves (computed using climatological and in situ stratification). The A waves travel ≈5%–10% faster than B waves until they reach the continental slope, presumably because of their greater amplitude. On the upper continental slope, all waves speed up relative to linear values, but B waves now travel 8%–12% faster than A waves, in spite of being smaller. Solutions of the Taylor–Goldstein equation with observed currents demonstrate that the B waves’ faster speed is a result of modulation of the background currents by an energetic diurnal internal tide on the upper slope. Attempts to ascertain the phase of the barotropic tide at which the waves were generated yielded inconsistent results, possibly partly because of contamination at the easternmost mooring by eastward signals generated at Luzon Strait’s western ridge. These results present a coherent picture of the transbasin evolution of the waves but underscore the need to better understand their generation, the nature of their nonlinearity, and propagation through a time-variable background flow, which includes the internal tides.

scholarly journals Investigation of Seiche Oscillations in the Adjacent Bays by the Example of the Sevastopol and the Quarantine Bays

2020 ◽  
Vol 27 (3) ◽  
Author(s):  
Yu. V. Manilyuk ◽  
D. I. Lazorenko ◽  
V. V. Fomin ◽  
◽  
◽  
...  
Keyword(s):  
Numerical Model ◽  
Numerical Experiments ◽  
Energy Exchange ◽  
Mutual Influence ◽  
Open Boundary ◽  
Computational Domain ◽  
Sea Level Fluctuations ◽  
Wave Disturbances ◽  
Sevastopol Bay ◽  
Seiche Oscillations

Purpose. The paper is aimed at studying the seiche structure in the adjacent bays' system of real configuration. Methods and Results. The response of the Sevastopol and Quarantine bays (Black Sea) to sea level fluctuations set at the open boundary of the computational domain has been studied. A number of random harmonics within the range of the eigen periods of these bays were used as fluctuations. The ADCIRC numerical model was applied for simulating. The numerical experiments were performed for three ranges obtained from the analytical estimates: 30–52, 8–30 and 1–15 min. The energy-bearing periods of seiche oscillations were revealed for both bays. The mutual influence of these bays was also studied. Conclusions. The above mentioned wave disturbances lead to generation of the seiche oscillations in the bays. For the Sevastopol Bay, their periods are 48, 22, 16, 10 and 6 min, for the Quarantine Bay – 11.4 and 4.8 min. The number of the generated modes is determined by the interval of the wave disturbance periods. The bays have a mutual influence on each other due to the wave energy exchange through their entrances. At that intensity of the eigen modes of the Sevastopol Bay penetrating the Quarantine Bay can exceed intensity of those of the Quarantine Bay. In both bays, the seiches with the largest amplitudes are induced by the disturbances, the periods of which are in the interval 30–52 min.

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