https://www.um.edu.mt/library/oar/handle/123456789/99839 Thu, 09 Apr 2026 17:20:52 GMT 2026-04-09T17:20:52Z https://www.um.edu.mt/library/oar/handle/123456789/136323 Title: Analysis of enhanced observations made by a SeaExplorer glider deployed in the central Mediterranean Abstract: As the Earth’s atmosphere continues to heat up and change the environment in unpredictable ways, it is necessary to not only have tools that are able to accurately predict future trends, but also to have an exact baseline of the studied properties to be able to accurately measure how these parameters may vary. The aim of this study is to verify existing oceanographic models and satellites in the Mediterranean Sea through the use of primary data collection on temperature, salinity, and chlorophyll-a through the use of an ocean glider. This ocean glider was deployed on a summer mission and a winter mission from areas along the Maltese Islands headed towards the northern coast of Africa, diving to depths of up to 700 metres. Ocean gliders are a branch of Underwater Autonomous Vehicles used for oceanographic measurements on a wide range of properties. During this time, satellite and model products were downloaded from an online service known as Copernicus Marine Environmental Monitoring Service which is widely relied upon across the world for policy making, climate monitoring, forecast predictions, and a realm of other services. All three datasets were uploaded to Matlab where the program could loop through to find the nearest model and satellite measurement in time and space to the nearest glider data point. A series of statistical analyses were performed to test the accuracy of the model and satellite products in comparison to the measured glider data. The accuracy between Missions 1 and 2 were also tested. These measurements included error bar plots, Mann-Whitney tests, correlations and Wilcoxon Signed Rank tests. A unique component of this study was the measure of correlation under certain conditions, this was done to determine if there were certain times or locations that the model or satellite products may be less accurate. These specific conditions measured were the correlation with the duration of the mission, with depth, and with the presence of backscattering. The key findings of this study included the importance of recalibration of the ocean glider perhaps earlier than what was previously predicted. Additionally, the reliability of using an ocean glider rather than model or satellite data when measuring any of the three parameters within the first 200 metres from the surface was realized. Finally, it was found that 95.5 percent of chlorophyll-a data points measured by the ocean glider were greater than the data points measured by the model, indicating there is likely an error with the model used for the chlorophyll-a product. Description: M.Sc.(Melit.) Sat, 01 Jan 2022 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/136323 2022-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/106954 Title: Geophysics and geomatics methods for coastal monitoring and hazard evaluation Abstract: The Maltese archipelago's northern region is experiencing a massive lateral spreading landslide. The region is distinguished by a coastal cliff environment with a hard coralline limestone outcropping layer sitting on a thick layer of clay. This geological formation causes coastal instability that results in rockfall and lateral spreading. This research has developed a methodology for high-precision monitoring of coastal cliff erosion using the integration of geomatics and geophysical techniques. From novel data collected by unmanned aerial vehicle (UAV) digital photogrammetry, a 3D digital model of the Selmun promontory was reconstructed and used to map and measure important geological features such as fractures, joints, and large boulders. Then, geophysical techniques such as electrical resistivity tomography and ground penetrating radar have been used for the identification and mapping of vertical fractures affecting the hard coralline limestone plateau and to validate the 3D geological model. In addition to this, high-precision orthophotos from UAV have been compared with aerial and satellite images captured between 1957 and 2021 and have been georeferenced into a GIS. The movement of boulders and cracks in rocks was then vectorised to highlight and quantify movement in time. The resulting data are then used to derive a qualitative assessment of the coastal variations in the geometric properties of the exposed discontinuity surfaces, to evaluate the volumes and the stop points of the observed rockfalls. Subsequently, a quantitative analysis was carried out through the use of the numerical simulation software RocPro 3D to reproduce the paths followed by the blocks and estimate different values such as speed, energy and stop points of the fallen blocks. Consequently, the source areas of past events were identified as well as potential source areas to simulate future events of unstable blocks on the cliff. The outcomes of this research were finally implemented in a GIS to offer a new approach for the collection and processing of coastal monitoring data which, ultimately, drives the local authorities to address social, economic and environmental issues of pressing importance and facilitates effective planning and mitigation of risks. Description: Ph.D.(Melit.) Sat, 01 Jan 2022 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/106954 2022-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/101445 Title: A preliminary hydrodynamical study around the island of Comino Abstract: The island of Comino is sought after by many tourists, especially in the warmer months between May and September. Its main attraction is the crystal-clear turquoise waters of the Blue Lagoon. Whilst being very picturesque, the water has been a struggle for many tourists over the years. The occasional strong and rapidly changing currents between Comino and Cominotto led to this unrepresented study to better understand the dynamics of the waters surrounding Comino. To carry out this study, two main data sources were utilised: a hydrodynamical coastal numerical model, which provided a three-dimensional hydrodynamic data around Comino, and the in-situ data from the deployed drifters. The sea surface currents and temperatures are processed through tailor-made MATLAB scripts to create trajectories based on the model output data and compared with drifters’ paths. When comparing the tracks produced by a 3 day spin up SHYFEM model and a 5 day spin up SHYFEM model, it was observed that the 5 day spin up modelled was able to reproduce tracks similar to those produced by the drifters. The sea surface temperature data as predicted by the 5 day spin up model was seen to be around 0.5◦C higher when compared to measurements from the deployed drifters. Description: B.Sc. (Hons)(Melit.) Sat, 01 Jan 2022 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/101445 2022-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/101444 Title: Evaluation, sensitivity and comparison of tsunami simulation programmes Abstract: Although large tsunamis in the Mediterranean Sea are not frequent it does not exclude their occurrence. Furthermore, the Maltese islands do not go unaffected by these events, as seen clearly during the 1908 Messina event. The increase in coastal development and enhancement of Malta’s tourist areas has further increased the risk imposed by tsunamis therefore, tsunami early warning systems (EWSs) are of utmost importance for the Maltese islands, as these areas would endure the greatest impact. Hence, the importance of the evaluation of the performance and sensitivity of TOAST (Tsunami Observation and Simulation Terminal), a tsunami simulation software installed at the University of Malta as an EWS. However, for TOAST to produce rapid results it utilizes coarse bathymetry that only extends to the periphery of ports and harbours. Therefore, its results are compared with those produced by HySEA (Tsunami-Hyperbolic Systems and Efficient Algorithms), a high-performance software package, specifically designed to simulate earthquake generated tsunamis that makes use of nested bathymetry data. The 365 AD Crete event was taken as the reference simulated event. Its location of 35.25 °N and 23.53 °E was used, with a magnitude of 8.5 and fault parameters: dip – 35°, strike – 315°, rake – 90°, length – 160 km, width – 80 km and depth – 10 km. It was concluded that the simulated wave heights and inundations were larger from TOAST than from HySEA, with a maximum wave height of 5.39 m (TOAST) and 4.37 m (HySEA). This overestimation from TOAST is attributed to the use of coarser bathymetry data for quick simulations resulting in estimations of run-up and wave heights at the coast. Description: B.Sc. (Hons)(Melit.) Sat, 01 Jan 2022 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/101444 2022-01-01T00:00:00Z