Estudio de los patrones de circulación sub-mesoescalares en el área del Estrecho de Gibraltar

A través del Estrecho de Gibraltar se realiza un importante intercambio de masas de agua entre las cuencas del océano Atlántico y el Mar Mediterráneo siguiendo el patrón de estuario inverso. De esta forma, existe un flujo medio de masas de agua desde el Atlántico hacia el Mediterráneo en una capa superior y un flujo medio de agua del Mediterráneo dirigiéndose hacia el Atlántico por una capa inferior. Sin embargo, existen indicios de que en la capa superior, de masas de agua predominantemente atlánticas, parecen establecerse contracorrientes y remolinos en los bordes costeros que deben afectar en alguna medida en los cálculos del transporte neto de agua atlántica hacia el Mediterráneo. Una evidencia experimental de la ocurrencia de estos procesos son las relativamente altas concentraciones de clorofila al oeste del Umbral Principal del Estrecho de Gibraltar, que pueden apreciarse en numerosas imágenes de satélite SEAWIF (SEA-viewing WIde Field-of-view sensor) de la zona. En esta memoria se presenta un análisis detallado de los procesos de transporte sub-mesoescalar que se desarrollan en el ámbito del Estrecho de Gibraltar y la región occidental del Mar de Alborán. Para detectar estos posibles patrones de circulación se han analizado registros de velocidad de la corriente obtenidos simultáneamente en los bordes costeros y en el canal central, así como registros de intensidad de corriente a partir de radares de alta frecuencia instalados en las costas de la península y Ceuta. El análisis se centra en la región del Umbral de Camarinal y, como hemos mencionado más arriba, en el Mar de Alborán occidental, haciendo especial hincapié en los procesos de transporte a través del Estrecho, las divergencias y convergencias en la zona central y los pequeños patrones de circulación sobre el margen costero Norte. Además, se estudiarán las consecuencias que tiene la variabilidad de las corrientes superficiales en el Estrecho de Gibraltar en el chorro atlántico, en el desarrollo y posterior separación del giro anticiclónico occidental del Mar de Alborán. Para ello se han empleado (además de los registros de velocidad arriba mencionados) imágenes SST procedentes de sensores AVHRR (de diferentes satélites NOAA) así como imágenes SST de alta resolución (7m) fundamentales en este estudio, adquiridas mediante un escáner hiperespectral aerotransportado. Esta información se complementa con los resultados de un experimento de liberación de rodamina, registros continuos de termosalinógrafo, perfiles de ADCP y la ejecución de un sencillo modelo numérico 2D

A New Method for the Collection of Marine Geomagnetic Information: Survey Application in the Colombian Caribbean

In recent years, the Oceanographic and Hydrographic Research Center (part of the General Maritime Directorate of Colombia (DIMAR) has made important efforts to advance research in the field of marine geophysics, in particular, the techniques of geomagnetism, sub-bottom profiling, and side-scan sonar, the first being the most developed at the present time. A method is presented for the acquisition of geomagnetic data in marine environments, as used by DIMAR in the Colombian maritime territory. The development of the geomagnetic method not only offers the opportunity to advance basic scientific knowledge, but it is also of great importance in support of national sovereignty issues. Among other applications, the most representative uses of the geomagnetic method are the location of pipelines and metal plates, detection of buried ordnance, identification of sites of archaeological interest, and the identification and characterization of geological structures. As a result of testing the method, a grid of geomagnetic data was surveyed in an area close to the Island of San Andres in the north-west of the Colombian maritime territory. The survey was prepared with a regional geometric arrangement, the result of which was compared with survey data obtained from the National Oceanic and Atmospheric Administration (NOAA) magnetic data repository and carried out in the same study area. Despite the long time interval between the two surveys, almost 50 years, no significant differences were observed in terms of the analyzed variables. Finally, results show negligible differences between the magnetic data obtained for the years 1970 and 2018 for all the variables measured, such as the inclination, declination, and total magnetic field. These differences may be attributable to a geological component or also to the acquisition and processing methods used in the 1970s.Caribbean Oceanographic and Hydrographic Research Center (CIOH

“On the shoulders of giants” the history of women and men in Physics as a teaching innovation in Engineering degrees

This paper describes the results of the teaching innovation project. It was putting into practice at the School of Engineering of the University of Cádiz during the academic year 2016/2017. It was called "If I have seen further it is because I am sitting on the shoulders of giants. A little history of Women and Men in the history of Science and Engineering in the classrooms of the Higher School of Engineering". The main objective of the project was to inform the students of the first year of the Degrees of Electricity, Industrial Electronics, Industrial Technology, Aerospace, about the biographies and the contributions of some of the "giants" of the Physics and Engineering. It supposed a recovery of the History of the Physics in the teaching in the Degrees of Engineering. Moreover, we have tried to make visible some of these researches, especially, the feminine scientists. The realization of this project has increased the motivation of the students for the learning of physics. Knowing the biographies, contributions, successes and failures of great scientists, predisposes students to understand more complex concepts and, at the same time, taking those giants as a source of inspiration

Meteorology for maritime students. Literature search for relevant information on meteorological subject and promotion of teamwork

The Teaching Innovation Project to which we refer below has been focused to pupils of the subject "Meteorology", taught in the third year of the degree in Nautical Sciences and Maritime Transport. Furthermore, the general and specific skills enhanced in the students through this project, are very useful for many other subjects on their degree. The implementation of this project sought the achievement of several learning objectives. First, it was intended to improve the student's preparation in the subject, trying to make more attractive for pupils the usually tedious process of searching and analysis of relevant bibliographic information, not only from an academic point of view, but also from the perspective of the future sailor. Secondly but not least, it has been tried to promote studying and working habits through team activities. Although individual work creates habits of personal reflection, since the student marks his own learning patterns, it carries the risk of leading to subjective interpretations that are little contrast; therefore, is necessary to find a way to properly combine individual and group work. To achieve the aforementioned objectives, this teaching project has enhanced the active work of the student by conducting activities of five members designing thematic posters (chosen from a list of proposed topics), which are later exposed and discussed publicly. Through continuous interaction with fellow students in the preparation of the posters, we have sought to foster critical and self-critical capacity, as well as constructive competition. It promotes creativity and increase the investment of the student in improving their training. A poster is a type of academic communication of great educational interest since, in addition to its obvious importance in the academic field, it provides educational benefits that will be briefly explained below. By having a limited space, the student is forced to develop their ability for synthesize, through the use of graphs, tables, images, etc. This in turn requires applying their capacity for analysis, discerning essential and superfluous concepts. At last, the public exposition and discussion increases the responsibility that falls on the student facing their peers, which positively affects to the quality of the work. This teaching project has been carried out throughout the corresponding semester. With this purpose, a certain number of hours of practical classes were assigned. This affords the student to devote more time for the accomplishment of his work, as well as it allows the teacher a punctual and immediate follow-up of its development. The chosen format (poster size) favoured the attainment of several of the didactic objectives sought, at the same time that it served as an introduction to the student in the methodologies and vehicles of knowledge broadcasting at the academic world

Influence of a Reef Flat on Beach Profiles Along the Atlantic Coast of Morocco

The North Atlantic coast of Morocco is characterised by a flat rocky outcrop in the south (Asilah Beach) and a sandy beach free of rocky outcrops in the north (Charf el-Akab). These natural beaches were monitored for a period of two years (April 2005-January 2007) and two different profiles (one for each beach) were analysed based on differences in the substrate. Topographic data were analysed using statistics and empirical orthogonal functions (EOFs) to determine beach slope and volumetric changes over time. Several morphologic phenomena were identified (accretion/erosion and seasonal tilting of beach profiles around different hinge points), attesting to their importance in explaining variability in the data. Periods of accretion were similar in both profiles, but the volumetric rate of change was faster in the sand-rich (SR) profile than in the reef flat (RF) profile. Moreover, the erosion rate for the SR profile was greater than the RF profile (135.18 m(3)/year vs. 55.39 m(3)/year). Therefore, the RF acted as a geological control on the evolution of its profile because of wave energy attenuation. Thus, special attention should be given to the RF profile, which has larger slopes, less amounts of mobilised sand, and slower erosion/accretion rates than the SR profile

The importance of sub-mesoscale processes for the exchange of properties through the Strait of Gibraltar

This article presents a detailed analysis of the sub-mesoscale transport processes in the Strait of Gibraltar. The interest is focussed on the Camarinal Sill region, and special attention is paid to the across-strait transport processes, the divergences and convergences in the central zone, and the small-scale circulation patterns along the northern coastal margin. The analysis is based on high-resolution (7 m) SST images acquired by an air-borne hyper-spectral scanner, and has been complemented with a rhodamine-release experiment, continuous thermo-salinograph records, acoustic Doppler current (ADCP) profiles from both moorings and vessel-mounted experiments, and numerical modelling. It is deduced from the analysis that the coupling between the upwelling processes, induced by the internal tide and the generation of large-amplitude internal waves, and the cyclonic eddies formed on the coastal margin, seems to be the mechanism that explains the chlorophyll maxima frequently found on the coastal margin of the studied area. Further, as a consequence of the small-scale patterns of circulation induced by the internal waves, the suspended substances are displaced from the coastal margins toward the central zones and later are carried by the westward current toward the convergence zones created by the internal waves, where they may be retained and accumulate. Then, in the eastward phase of the tidal current over the Camarinal Sill, these nuclei of concentrated substances (nutrients, chlorophyll, and plankton) are transported toward the Alboran Sea, where they must contribute, in part, to the primary productivity there

Establecimiento de una red limnimetrica en las hidrovías de la Amazonia peruana

La determinacion del nivel de referencia vertical y la pendiente hidraulica en las hidrovias de la Amazonia peruana es un problema que afecta a la seguridad de la navegación y a los proyectos de ingenieria e investigacion. Actualmente, no se cuenta con un nivel de referencia vertical relacionado al nivel medio del mar ni al datum altimetrico de Peru

Aprendizaje procedimental y nuevas tecnologías en la formación de alumnos en la asignatura de formación marítima básica.

La Escuela de Ingenierías Marina, Náutica y Transporte Marítimo y Radioelectrónica de la Universidad de Cádiz (EIMANAR) está en pleno proceso de transición al nuevo sistema educativo acorde al Espacio Europeo de Educación Superior (EEES). Las nuevas tecnologías pueden introducirse en algunas asignaturas profesionales que son fundamentales en la formación del futuro Oficial de Marina Mercante. Su aplicación a casos reales, de una manera objetiva y práctica, nos ofrece la posibilidad de mejorar el aprendizaje y el rendimiento de los estudiantes. Por primera vez en la EIMANAR se va a implementar una práctica experimental en la asignatura de Formación Marítima Básica (FMB) con la utilización de nuevas tecnologías, que facilitará a los alumnos la comprensión de los conceptos fundamentales de navegación costera. Utilizaremos receptores GPS de navegación de bajo costo y herramientas de software libre, entre ellos el Google Earth. La práctica es obligatoria y será evaluada de forma conjunta con las prácticas de navegación a bordo del Velero Escuela Tartessos y otros trabajos prácticos de la asignatura que serán enviados por el campus virtual. Con la práctica además de mejorar los conocimientos de los alumnos en la asignatura, esperamos proporcione las siguientes ventajas en la mejora del proceso de aprendizaje: * Introducir a los alumnos en el e-learning y en el mundo de las nuevas tecnologías y sus aplicaciones en casos reales y profesionales. * Aprender y/o actualizar conceptos fundamentales de navegación costera y aplicarlos de forma objetiva y con la ayuda y el uso de nuevas tecnologías * Comprobar el progreso en el aprendizaje de los alumnos durante la realización de la práctica, mediante controles realizados a través del campus virtual. * Facilitar nuevo material didáctico y el uso de nuevos medios para mejorar la comprensión y el estudio de la asignatura. Al final del curso se evaluará el éxito de esta iniciativa mediante el análisis comparativo de las notas obtenidas en cursos anteriores y la realización de una encuesta sobre la satisfacción de los alumnos con esta nueva metodología

The fate of Guadalquivir River discharges in the coastal strip of the Gulf of Cadiz. A study based on the linking of watershed catchment and hydrodynamic models.

A catchmentmodel for river basins and a hydrodynamicmodelwere combined in order to simulate the spreading of the turbidity plume produced by sediment discharges from the Guadalquivir River basin within the Gulf of Cádiz under different meteorological conditions. The current fields provided by the hydrodynamic model and a transport-diffusion scheme based on tracking virtual particles tracking released at the river mouth have enabled us to simulate turbidity plumes that show great similarity with the plumes observed in satellite images. The most relevant results of the study show that in the absence of winds, the plume tends to spread very slowly, gradually progressing northwards; this is because of the symmetry between the filling and draining flows at the mouth of the Guadalquivir and low intensity of the tidal currents beyond the mouth. In addition, the transport of the plume towards the Strait of Gibraltar requires wind conditions with a northerly, north-westerly or westerly component. Westwards transport, however, requires winds with an easterly, southerly, or south-easterly component. The periods of heaviest rainfall in the Guadalquivir River basin coincide with winds mainly from the west; therefore, the times ofmaximum discharge at the mouth of the river occurwhen there are wind conditions that favour the transport of the matter suspended in the plume, southwards along the coast, towards the Strait of Gibraltar and the Alboran Sea. Linking the watershed catchment and hydrodynamic models has proved its suitability to predict the evolution and reaching of the sediment plumes fromthe Guadalquivir River discharges and the experience encourages the use of that methodology to be applied in a future prediction systemfor the creation and evolution of those sediment plumes.We would like to thank the Regional Government of Andalusia ( P11-RNM-7722 project), the Spanish Government (TRUCO project RTI2018-100865-B-C22 ), the SUDOE INTERREG AGUAMOD and OCASO projects for supporting this work financially. We are also grateful to NASA for distributing the MODIS data used in this study, and to the AERONET project for the MODIS AQUA RGB True Color Images, especially those from the Malaga-San Jose and Huelva stations

Error on the Estimation of Sand Size Parameters When Using Small Diameter Sieves and a Solution

Analyses were carried out to determine the main sand size parameters (median grain size D-50 and sorting sigma) for beach nourishment purposes using the sieving method aboard a dredger. Due to a lack of space and the need to carry and use the material with ease, the sieves are commonly small (10 cm diameter), and the shaking procedure is usually performed by hand. However, the influence of shaking, either mechanically or manually, has not yet been studied with 10 cm diameter sieves. Therefore, 20 samples were taken from inside the hopper of a trailing suction dredger and sieved both manually and mechanically for 10 min. The results showed that manual sieving yielded higher D-50 values than the mechanical procedure. The average error arising from using the manual method was 14%, but it can reach 36.5%. The granulometric analysis carried out for different shaking times has shown that this error is < 5% when at least 20 min of shaking is performed. The mechanical procedure gave always finer sand results. In addition, the overfill ratio calculated for both mechanical and manual results reached differences of up to 48