Analysis of tidal flows through the Strait of Gibraltar using Dynamic Mode Decomposition

The Strait of Gibraltar is a region characterized by intricate oceanic sub-mesoscale features, influenced by topography, tidal forces, instabilities, and nonlinear hydraulic processes, all governed by the nonlinear equations of fluid motion. In this study, we aim to uncover the underlying physics of these phenomena within 3D MIT general circulation model simulations, including waves, eddies, and gyres. To achieve this, we employ Dynamic Mode Decomposition (DMD) to break down simulation snapshots into Koopman modes, with distinct exponential growth/decay rates and oscillation frequencies. Our objectives encompass evaluating DMD's efficacy in capturing known features, unveiling new elements, ranking modes, and exploring order reduction. We also introduce modifications to enhance DMD's robustness, numerical accuracy, and robustness of eigenvalues. DMD analysis yields a comprehensive understanding of flow patterns, internal wave formation, and the dynamics of the Strait of Gibraltar, its meandering behaviors, and the formation of a secondary gyre, notably the Western Alboran Gyre, as well as the propagation of Kelvin and coastal-trapped waves along the African coast. In doing so, it significantly advances our comprehension of intricate oceanographic phenomena and underscores the immense utility of DMD as an analytical tool for such complex datasets, suggesting that DMD could serve as a valuable addition to the toolkit of oceanographers

Program and Abstracts of the Annual Meeting of the Georgia Academy of Science, 2014

The annual meeting of the Georgia Academy of Science took place March 28-29, 2014, at Georgia Regents University, Augusta, Georgia. Presentations were provided by members of the Academy who represented the following sections: I. Biological Sciences II Chemistry III. Earth & Atmospheric Sciences IV. Physics, Mathematics, Computer Science, Engineering & Technology V. Biomedical Sciences VI. Philosophy & History of Science VII. Science Education VIII. Anthropology

Program and Abstracts of the Annual Meeting of the Georgia Academy of Science, 2011

The annual meeting of the Georgia Academy of Science took place March 23–24, 2011, at Gainesville State College, Oakwood, Georgia. Presentations were provided by members of the Academy who represented the following sections: I. Biological Sciences, II. Chemistry, III. Earth & Atmospheric Sciences, IV. Physics, Mathematics, Computer Science, Engineering & Technology, V. Biomedical Sciences, VI. Philosophy & History of Science, VII. Science Education, and VIII. Anthropology

Progression magazine Spring 2013

Progression Magazine is published by the Gupta College of Science at Coastal Carolina University and highlights the marine-related work of the students, faculty, and staff, events, and educational and research information of students and faculty

Program and Abstracts of the Annual Meeting of the Georgia Academy of Science, 2013

The annual meeting of the Georgia Academy of Science took place March 29-30, 2013, at Valdosta State University, Valdosta, Georgia. Presentations were provided by members of the Academy who represented the following sections: I. Biological Sciences II Chemistry III. Earth & Atmospheric Sciences IV. Physics, Mathematics, Computer Science, Engineering & Technology V. Biomedical Sciences VI. Philosophy & History of Science VII. Science Education VIII. Anthropology

Laver and set theory

In this commemorative article, the work of Richard Laver is surveyed in its full range and extent.Accepted manuscrip

ASSESSMENT METHODOLOGY OF PERMEABILITY IN A GRANITIC AQUIFER IN A PILOT BASIN IN THE SOUTH OF SARDINIA (ITALY)

Groundwater circulation in fractured hard rocks aquifer (HRA) is an essential element in the fields of water supply, environment and geotechnics. The fracture properties, as orientation, size, abundance, and quality, influence the circulation of water. The geometry of the fractures makes the hydrogeological environment anisotropic and heterogeneous. Hence, defining the geological model is fundamental to understand spatial variability of permeability, and to define hydrogeological features of the aquifers. The present work aimed to develop a methodology to assess the permeability on crystalline rocks. As a pilot site, the Masoni Ollastru River basin (12,5 km2) in the South of Sardinia was considered. The reconstruction of the fracture network required a multiscale characterisation using field measurements and digital photogrammetry. The fractures field survey consisted in recording the features of discontinuities. The digital photogrammetry workflow produced a high resolution DEM (5m), orthophotos, digital stereo pairs, and a lineaments map. For each 11 geomechanical stations, the set of joints was characterized and the permeability was calculated applying the Darcy’s cubic law (three dimensional Darcy’s law or only cubic law) for each set. Spatial distribution of fracture properties was evaluated to approach the heterogeneity of the medium. For this purpose, two different scenarios in the geological conceptual model were evaluated: the first one concerns a stratiform aquifer with a sub-horizontal and sub-vertical fissured layer in the paleo-weathering profile of the granites; the second one regards valley incision by differential erosion determined by structural features (fractures density). The layer of unconsolidated alterite above the granitic paleo-weathering profile is thin and seems to represent the deeper level where the rocks are less weathered and fractured. Probably, the significant erosion of the large part of the saprolite is related to an uplift after Pliocene time. The permeability calculated with the cubic law was in a range of 10-8 to 10-2 m/s; the highest values are conditioned by the fractures aperture in the surface. According to the geological conceptual model, density and aperture of fractures decreases with depth, thus also permeability. The applied multi-phase methodology with a multiscale approach allowed to provide a hydrogeological conceptual model in a HRA