Internal wave generation and its impact at the island Shelf
type: CreativeWork
description: This doctoral dissertation provides an integrated analysis of island-shelf circulation and the generation of nonlinear internal waves (NIWs) in the Madeira Archipelago, a region characterized by steep bathymetry, a narrow insular shelf, and strong atmosphere–ocean interactions. Although Madeira has been widely studied in terms of wake dynamics, mesoscale variability, and wind–island interactions, no systematic assessment of internal wave generation had been conducted in this area of the northeastern Atlantic. This thesis addresses this major gap by combining in-situ observations, satellite imagery, and high-resolution numerical modeling. The first component examines island-shelf circulation under different forcing regimes, including tides, local winds, and large-scale background flow. A high-resolution (1 km) COAWST configuration is used together with ADCP measurements, meteorological stations, Sentinel imagery, and surface drifters. Results show that Madeira’s coastal circulation is governed by the superposition of these forcings, producing alternating patterns of retention, recirculation, and coastal transport. The spatial heterogeneity of these patterns is strongly controlled by the steep and irregular island topography. The second component presents the first direct observational evidence of NIW generation along the ridge connecting Madeira and the Desertas Islands. Using long-term mooring data, a Wirewalker profiler, a thermistor chain, and hydrographic observations, the analysis documents isopycnal displacements, internal bores, and phase-dependent variations of the Froude number associated with the barotropic tidal cycle. Both Sentinel-1 SAR and Sentinel-2 optical imagery reveal surface signatures consistent with internal wave fronts aligned with the ridge. Based on these observations, a new conceptual model is proposed linking tidal-phase transitions, subcritical–supercritical flow regimes, and the periodic release of nonlinear internal waves. The third comp…
abstract: This doctoral dissertation provides an integrated analysis of island-shelf circulation and the generation of nonlinear internal waves (NIWs) in the Madeira Archipelago, a region characterized by steep bathymetry, a narrow insular shelf, and strong atmosphere–ocean interactions. Although Madeira has been widely studied in terms of wake dynamics, mesoscale variability, and wind–island interactions, no systematic assessment of internal wave generation had been conducted in this area of the northeastern Atlantic. This thesis addresses this major gap by combining in-situ observations, satellite imagery, and high-resolution numerical modeling. The first component examines island-shelf circulation under different forcing regimes, including tides, local winds, and large-scale background flow. A high-resolution (1 km) COAWST configuration is used together with ADCP measurements, meteorological stations, Sentinel imagery, and surface drifters. Results show that Madeira’s coastal circulation is governed by the superposition of these forcings, producing alternating patterns of retention, recirculation, and coastal transport. The spatial heterogeneity of these patterns is strongly controlled by the steep and irregular island topography. The second component presents the first direct observational evidence of NIW generation along the ridge connecting Madeira and the Desertas Islands. Using long-term mooring data, a Wirewalker profiler, a thermistor chain, and hydrographic observations, the analysis documents isopycnal displacements, internal bores, and phase-dependent variations of the Froude number associated with the barotropic tidal cycle. Both Sentinel-1 SAR and Sentinel-2 optical imagery reveal surface signatures consistent with internal wave fronts aligned with the ridge. Based on these observations, a new conceptual model is proposed linking tidal-phase transitions, subcritical–supercritical flow regimes, and the periodic release of nonlinear internal waves. The third comp…
author: Da Costa Dos Reis, Jesús Leonel
language: eng
keywords: circulación insular, ondas internas no lineales, COAWST, Madeira–Desertas Ridge, estratificación, mezcla vertical, nonlinear internal waves, island-shelf circulation, stratification, vertical mixing
license: http://creativecommons.org/licenses/by-nc-nd/4.0/
date published: 2026
date modified: 2026-07-24T01:29:34Z
provider: Universidad de Cadiz
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universidad de Cadiz

PropertyValue
property ID: Handle
value: http://hdl.handle.net/10498/39781