On the role of SAR for observing "local generation" of internal solitary waves off the Iberian Peninsula

2007 ◽  
Vol 33 (5) ◽  
pp. 388-403 ◽  
Author(s):  
J C.B. da Silva ◽  
A L New ◽  
A. Azevedo
Keyword(s):  
Iberian Peninsula ◽  
Solitary Waves ◽  
Internal Solitary Waves ◽  
Local Generation

scholarly journals Generation of internal solitary waves in a pycnocline by an internal wave beam: a numerical study

2011 ◽  
Vol 676 ◽  
pp. 491-513 ◽  
Author(s):  
N. GRISOUARD ◽  
C. STAQUET ◽  
T. GERKEMA
Keyword(s):  
Solitary Waves ◽  
Western Europe ◽  
Numerical Study ◽  
Western Indian Ocean ◽  
Internal Solitary Waves ◽  
Generation Process ◽  
Hydrostatic Model ◽  
Direct Generation ◽  
Local Generation ◽  
Selection Of

Oceanic observations from western Europe and the south-western Indian ocean have provided evidence of the generation of internal solitary waves due to an internal tidal beam impinging on the pycnocline from below – a process referred to as ‘local generation’ (as opposed to the more direct generation over topography). Here we present the first direct numerical simulations of such a generation process with a fully nonlinear non-hydrostatic model for an idealised configuration. We show that, depending on the parameters, different modes can be excited and we provide examples of internal solitary waves as first, second and third modes, trapped in the pycnocline. A criterion for the selection of a particular mode is put forward, in terms of phase speeds. In addition, another simpler geometrical criterion is presented to explain the selection of modes in a more intuitive way. Finally, results are discussed and compared with the configuration of the Bay of Biscay.

scholarly journals Reflecting tidal wave beams and local generation of solitary waves in the ocean thermocline

2007 ◽  
Vol 593 ◽  
pp. 297-313 ◽  
Author(s):  
T. R. AKYLAS ◽  
R. H. J. GRIMSHAW ◽  
S. R. CLARKE ◽  
ALI TABAEI
Keyword(s):  
Continental Shelf ◽  
Solitary Waves ◽  
Numerical Solutions ◽  
Wave Beam ◽  
Incident Beam ◽  
Tidal Wave ◽  
Internal Solitary Waves ◽  
Long Wave ◽  
Lower Fluid ◽  
Local Generation

It is generally accepted that ocean internal solitary waves can arise from the interaction of the barotropic tide with the continental shelf, which generates an internal tide that in turn steepens and forms solitary waves as it propagates shorewards. Some field observations, however, reveal large-amplitude internal solitary waves in deep water, hundreds of kilometres away from the continental shelf, suggesting an alternative generation mechanism: tidal flow over steep topography forces a propagating beam of internal tidal wave energy which impacts the thermocline at a considerable distance from the forcing site and gives rise to internal solitary waves there. Motivated by this possibility, a simple nonlinear long-wave model is proposed for the interaction of a tidal wave beam with the thermocline and the ensuing local generation of solitary waves. The thermocline is modelled as a density jump across the interface of a shallow homogeneous fluid layer on top of a deep uniformly stratified fluid, and a finite-amplitude propagating internal wave beam of tidal frequency in the lower fluid is assumed to be incident and reflected at the interface. The induced weakly nonlinear long-wave disturbance on the interface is governed in the far field by an integral-differential equation which accounts for nonlinear and dispersive effects as well as energy loss owing to radiation into the lower fluid. Depending on the strength of the thermocline and the intensity of the incident beam, nonlinear wave steepening can overcome radiation damping so a series of solitary waves may arise in the thermocline. Sample numerical solutions of the governing evolution equation suggest that this mechanism is quite robust for typical oceanic conditions.

scholarly journals Numerical simulations of the local generation of internal solitary waves in the Bay of Biscay

2010 ◽  
Vol 17 (5) ◽  
pp. 575-584 ◽  
Author(s):  
N. Grisouard ◽  
C. Staquet
Keyword(s):  
Numerical Simulations ◽  
Solitary Waves ◽  
Generation Mechanism ◽  
Internal Solitary Waves ◽  
Bay Of Biscay ◽  
Two Dimensional ◽  
Background Flow ◽  
Nonhydrostatic Model ◽  
Wave Trains ◽  
Local Generation

Abstract. Oceanic observations from the Bay of Biscay, Portugal, Mozambique Channel and Mascarene Ridge have provided evidence of the generation of internal solitary waves due to an internal tidal beam impinging on the thermocline from below – a process referred to as "local generation". Here we present two-dimensional numerical simulations with a fully nonlinear nonhydrostatic model of situations that are relevant for the Bay of Biscay in summer. We show that a beam impinging on a thermocline initially at rest can induce a displacement of the isopycnals, large enough for internal solitary waves to be generated. These internal solitary waves however differ from those observed in the Bay of Biscay through their amplitude and distance between wave trains. We then show that the latter feature is recovered when the background flow around the thermocline as found in the Bay of Biscay is included in the forcing, thereby yielding a more accurate view on the local generation mechanism.

scholarly journals Conjugate flows and amplitude bounds for internal solitary waves

2009 ◽  
Vol 16 (2) ◽  
pp. 169-178 ◽  
Author(s):  
N. I. Makarenko ◽  
J. L. Maltseva ◽  
A. Yu. Kazakov
Keyword(s):  
Solitary Waves ◽  
Density Profile ◽  
Nonlinear Waves ◽  
Stratified Flows ◽  
Internal Solitary Waves ◽  
Fine Scale ◽  
Strongly Nonlinear ◽  
The Mean ◽  
Conjugate Flows

Abstract. Amplitude bounds imposed by the conservation of mass, momentum and energy for strongly nonlinear waves in stratified fluid are considered. We discuss the theoretical scheme which allows to determine broadening limits for solitary waves in the terms of a given upstream density profile. Attention is focused on the continuously stratified flows having multiple broadening limits. The role of the mean density profile and the influence of fine-scale stratification are analyzed.

The Role of Politics in the Historical Transport Networks of the Iberian Peninsula and the Pyrenees from Roman Times to the Nineteenth Century

2021 ◽  
Vol 45 (2) ◽  
pp. 233-260
Author(s):  
Pau de Soto ◽  
Cèsar Carreras
Keyword(s):  
Iberian Peninsula ◽  
Social Factors ◽  
Transport Network ◽  
Political Organization ◽  
Transport Systems ◽  
The Political ◽  
Political Systems ◽  
Transport Networks ◽  
Political Economic

AbstractTransport routes are basic elements that are inextricably linked to diverse political, economic, and social factors. Transport networks may be the cause or result of complex historical conjunctions that reflect to some extent a structural conception of the political systems that govern each territory. It is for this reason that analyzing the evolution of the transport routes layout in a wide territory allows us to recognize the role of the political organization and its economic influence in territorial design. In this article, the evolution of the transport network in the Iberian Peninsula has been studied in a broad chronological framework to observe how the different political systems of each period understood and modified the transport systems. Subsequently, a second analysis of the evolution of transport networks in the northeast of the Iberian Peninsula is included in this article. This more detailed and geographically restricted study allows us to visualize in a different way the evolution and impact of changes in transport networks. This article focuses on the calculation of the connectivity to analyze the intermodal transport systems. The use of network science analyses to study historical roads has resulted in a great tool to visualize and understand the connectivity of the territories of each studied period and compare the evolution, changes, and continuities of the transport network.

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