https://www.um.edu.mt/library/oar/handle/123456789/11473 Thu, 22 Oct 2026 14:47:51 GMT 2026-10-22T14:47:51Z https://www.um.edu.mt/library/oar/handle/123456789/150269 Title: Mapping maritime pollution risk and coastal vulnerability around Malta Abstract: Maritime transport is essential to global trade and island connectivity, but it also creates persistent environmental risks for coastal states located near major shipping corridors. Malta is particularly exposed because of its central Mediterranean position, proximity to dense cargo and tanker traffic, and dependence on coastal resources, tourism, fisheries, and marine infrastructure. This project assessed maritime pollution risk and coastal vulnerability around the Maltese Islands by integrating Automatic Identification System (AIS) vessel-position data, OpenDrift oil-spill simulations, and GIS-based shoreline exposure mapping. AIS data were used to identify two maritime corridors of interest; an offshore northern corridor, and a nearshore south-eastern corridor. Randomized release points were generated within these corridor boundaries and used as starting locations for OpenDrift/OpenOil simulations of a 10 cubic meters generic diesel release under selected wind, wave, and surface-current conditions. Model outputs were exported as particle trajectory data and mapped in GIS to evaluate offshore dispersion, nearshore movement, and coastal-contact patterns. Results showed that offshore scenarios generally remained separated from the Maltese coastline during the modelled period, while nearshore scenarios produced greater coastal relevance, including trajectories moving adjacent to Malta and particles classified as stranded or coastal-contact points. Coastal-contact locations were spatially uneven, with exposure concentrated along selected eastern, south-eastern, and southern shoreline sectors. These findings indicate that maritime pollution risk around Malta is shaped by the interaction between vessel location, environmental forcing, release proximity, and coastal receptors. The workflow provides a spatial decision-support framework for monitoring, emergency-response planning, and future coastal vulnerability assessment. Description: MSc. (EMS)(Melit.) Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/150269 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/150267 Title: Marine heatwaves in the central Mediterranean : frequency and spatial distribution (2008-2025) Abstract: The Mediterranean Sea is warming faster than the global ocean average, making its semi enclosed, relatively shallow basin particularly exposed to extreme thermal events. Marine Heatwaves (MHWs), prolonged periods of anomalously high ocean temperature, offer an ecologically meaningful way to characterize this warming because they capture disruptive extremes rather than gradual mean trends. This study quantifies the frequency of surface MHWs in the waters around the Maltese Islands, including the 12-nautical-mile territorial sea and the 25-nautical-mile Fisheries Management Zone (FMZ), over a 17-year period from 2008-2025. Daily ultra-high-resolution sea surface temperature analyses from the Copernicus Marine Service were used to construct, for every grid cell, a seasonally varying daily 90thpercentile threshold. Following the minimum-duration criterion of Hobday et al. (2016), periods in which temperature exceeded this threshold for at least five consecutive days were classified as MHW events, and events were counted for every grid cell and mapped across the domain. A representative cell south of Malta was used to validate the detection procedure. Across the domain, the mid-August 90th-percentile threshold ranged from 27.7 °C to 29.6 °C (mean 28.6 °C), and the number of detected events per grid cell over the study period ranged from 26 to 53, with a domain mean of approximately 40. Exposure was spatially uneven. Event frequency was highest in the western and northwestern waters and lowest in the waters immediately south and southeast of the Maltese Islands. At the validation cell, 37 events were detected, and threshold exceedances recurred in most summers, becoming more frequent toward the end of the record, with the warmest peak in 2023. These results show that recurrent surface thermal extremes are pervasive but spatially structured across Maltese waters, with direct relevance to fisheries management, marine spatial planning, and climate-adaptation planning. Methodological limitations, including a simplified climatology, a surface-only focus, and a baseline drawn from a warming period, are discussed, and depth-resolved analysis is identified as a priority for future work. Description: MSc. (EMS)(Melit.) Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/150267 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/150266 Title: Heat, growth, and space : a geospatial analysis of land use development and thermal change in Malta Abstract: Urban Heat Island (UHI) has become an increasingly important environmental challenge as urbanization intensifies, leading to elevated surface temperatures that affect public health, energy consumption, and environmental sustainability. This study investigates the spatial and temporal evolution of land surface temperature (LST) across Malta between 1985 and 2025 and examines the relationship between land use change and the urban heat island effect. Landsat imagery was processed using Google Earth Engine and ArcGIS products to derive LST datasets, while supervised land cover classifications were used to quantify changes in urban, vegetative, and barren land. Annual averages of monthly median and maximum temperatures were analyzed for individual local councils using zonal statistics and time-series analysis. Results indicate that highly urbanized councils, including Birkirkara, Hamrun, Santa Venera, and Luqa, consistently recorded higher LST than less urbanized councils such as Fontana, Ghasri, and Rabat (Gozo). While regional climate variability produced synchronized warm and cool periods across the islands, urban areas exhibited greater thermal intensity and more pronounced temperature extremes, particularly during warming events in the early 2000’s and mid 2000’s. The findings demonstrate a strong relationship between urban development and elevated LST, confirming the persistence of the urban heat island effect across Malta over the past four decades. This research provides a long-term assessment since Landsat images have become available to assess urban thermal patterns and identify vulnerable regions, and offers evidence to support sustainable planning strategies, including increased vegetation cover and green infrastructure to mitigate future heat-related impacts. Description: MSc. (EMS)(Melit.) Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/150266 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/150229 Title: Green roofs and compact infiltration systems in Malta : a modelled assessment of runoff and peak-flow reduction for urban flash flood mitigation Abstract: Flash flooding is a type of hazard characterised by intense rainfall over a relatively short period (Abegaz et al., 2024), significant economic and health harms (Alipour et al., 2020), and a pattern of accelerating increase in terms of frequency and intensity due to climate change. Additionally, urbanised areas are particularly vulnerable to hazards associated with these extreme weather events, due to their traits of impermeability that increase runoff generation. Within Malta, flood risks have also been intensified by the inconsistent implementation of adaptation measures, particularly the integration of rainwater cisterns into buildings. Although rainwater cisterns have long been required by law and form part of Malta’s traditional approach to rainwater management, periods of rapid development have seen these measures overlooked or inadequately implemented. Consequently, rainfall that could otherwise be stored or managed on site is often discharged directly onto streets, contributing to surface runoff and urban flooding. This study describes and compares the potential benefits of individual and combined green stormwater infrastructure (GSI) measures through their effectiveness in reducing flood impacts, especially flash flooding, in terms of reductions in total runoff contribution and peak flow. The individual and combined impacts of both green roof and compact infiltration system (CIS) GSI are explored. Green roof GSI refers to rooftops that utilise green space, incorporating vegetation and soil, to manage overflowing stormwater through absorption and retention. Alternatively, CISs are infiltration systems developed locally within Malta through a research project named GEO-INF conducted by Ing Marco Cremona, and are characterised by their compact size, low costs, and low maintenance (Green Stormwater Infrastructure Guidance Manual, 2022). These potential benefits in mitigation effectiveness are explored within an 8028 m2 study area within Birkirkara, Malta; a densely populated and heavily urbanised area known for flooding downstream. These GSI types are explored through modelled simulations in Stella Architect, based on Maltese weather data and GSI data from current GSI projects, with the express purpose of testing mitigation effectiveness across a variety of storms that emphasise current averages, increasing intensities, and increasing temporal scales. In total, four scenarios were modelled and tested for effectiveness, including no GSI implementation, green roof, CIS, and integrated green roof and CIS implementation. The results of this study show a substantial runoff contribution reduction across all scenarios featuring GSI, with the integrated green roof and CIS scenario mitigating approximately 100% of runoff contributions and peak flow rates across all storm scenarios. The CIS scenario showed complete mitigation in scenarios where its capacity was reached; however, in other scenarios, increased runoff and especially peak flow rates occurred. Green roofs showed greater resilience across all storms and held an 88% runoff reduction percentage against storm seven, as opposed to the 37% runoff reduction percentage exhibited by the CIS scenario in the same storm event. Finally, the GSI scenarios were analysed under varying roof area and CIS tank size configurations to find further optimisation opportunities, with significant tank size reductions being found to be effective for the combined green roof and CIS scenario. This study holds implications for the tradeoffs present across different GSI configurations, through the comparisons identified and the overall evidence for the effectiveness of alternatives and complements to conventional stormwater drainage infrastructure, including rainwater cisterns. Overall, this study addresses knowledge gaps relating to key GSI types that will be necessary to reduce the increasing impacts of flash flooding events, as they grow in intensity and frequency, due to climate change. Description: MSc. (EMS)(Melit.) Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/150229 2026-01-01T00:00:00Z