CIM3-Livros (ou partes, com ou sem arbitragem científica)
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- Storm impact assessment for Scotland’s wave-dominated sedimentary coastsPublication . Horsburgh, Nicola; Loureiro, Carlos; Hurst, Martin; Rennie, Alistair; Tyler, AndrewAlong wave-dominated sedimentary coasts, risks posed by chronic coastal erosion and rising sea levels during this century have received much atten-tion. However, extreme wave runup during large storms are still poorly charac-terised at large spatial scales, and can contribute significantly to coastal flooding and erosion. This creates an important challenge for coastal management and adaptation planning. This work presents a national-scale storm impact assessment for Scotland’s wave-dominated sand and gravel coasts. It uses readily available national and European datasets to model extreme total water levels that include storm wave runup, tides, storm surge and changes in mean sea level. Future impacts are assessed by integrating likely climate-driven changes to storm forcing and coastal morphology. Outputs estimate the likely storm impact regime at 50 m alongshore transects in Scotland’s natural sand and gravel coasts for the present day, 2050 and 2100, considering climate change scenarios RCP4.5 and RCP8.5. Results indicate 65%, 11% and 4% of transects currently experience collision, overwash and inundation as the most severe storm impact. Towards 2100, tran-sects in overwash and inundation increase to 20% (22%) for RCP4.5 (RCP8.5), but local increases vary considerably between coastal cells. This study contributes to a strategic, national scale understanding of coastal risk that supports the spatial prioritisation of areas in need of proactive adaptation solutions.
- Can global datasets be used to predict storm-induced coastal erosion?Publication . Fanti, Valeria; Ferreira, Óscar; Loureiro, CarlosThe scarcity of high-resolution in situ data hampers effective storm impact assessment and the development of early warning systems for coastal bar riers worldwide. This study introduces a novel methodology utilising a SWAN XBeach modelling chain, leveraging global hydrodynamic (WAVERYS and GTSM) and topo-bathymetric (TanDEM-X and ETOPO2022) datasets to perform first-order, globally applicable storm impact assessments for barrier coasts. The approach is validated with high-resolution data from Duck, North Carolina, using pre- and post-storm topographic LiDAR, recorded wave conditions and water levels. The results indicate that global datasets can reasonably reproduce barrier ero sion patterns, despite underestimation of total water levels and dune morphology due to the coarse resolution and inaccuracies in the GTSM and TanDEM-X data. The simulations effectively capture dune retreat and erosion trends, aligning with measured data, but inconsistencies are observed in morphological changes for the upper beach face. These discrepancies are likely due to differences in intertidal elevation and beach face steepness between the LiDAR data and global models at Duck. Additionally, the approach does not account for short-scale (~100 m) longshore variability, which can contribute to deviations in modelled results. This study demonstrates the potential of global datasets for storm impact mod elling, providing a first-order assessment with relevant information about storm induced erosion, which can be particularly useful in areas lacking high resolution data. However, it also highlights the need for further validation across diverse sites to enhance reliability and address methodological constraints.
- Decoding storm response in geologically controlled coastal barriers using XBeachPublication . Kümmerer, Vincent; Loureiro, Carlos; Ferreira, ÓscarStorm-induced morphological changes in coastal barriers are primar ily driven by hydrodynamic forcing. However, in rock-fronted coasts the pres ence of geological features can modulate storm impacts, but the extent to which these non-dynamic variables influence barrier morphological response to storms is still poorly understood. This study explores the influence of intertidal rock plat forms on storm-driven morphological changes. Using the process-based XBeach model, dune erosion during an energetic winter storm was simulated across dif ferent schematic cross-shore profiles, incorporating variable intertidal rock plat form configurations. The schematic profiles are based on existing barrier pro files in the Outer Hebrides, NW Scotland. Calibration of the model involved adjusting friction coefficients of exposed bedrock surfaces to improve the abil ity to reproduce observed nearshore wave heights and morphological changes in pre- and post-storm profiles. The results show that higher intertidal rock plat forms (above mean sea level) are associated with reduced dune erosion, while lower rock platforms are associated with more extensive dune erosion. This high lights the complex interaction between geological control and storm impacts, with implications for improved understanding of coastal resilience and storm-driven morphosedimentary dynamics in rock-fronted barrier systems.
- Unravelling the response of the Guadiana ebb-tidal delta to extreme wave eventsPublication . Rubio, Carlos; Garel, Erwan; Zarzuelo, Carmen; López-Ruiz, AlejandroThis study investigates the morphodynamic response of the Guadiana ebb-tidal delta to extreme wave storms using a process-based numerical model. Field data including wave climate, wind and bathymetry were integrated into the Delft3D model, calibrated and validated with hydrodynamic data collected at the lower estuary in 2013, 2015 and 2023 and bathymetric maps of the ebb delta from 2016 and 2017. The analysis focuses on the impact of Storm Emma (February-March 2018), characterised maximum wave height up to 7.1 m. Results show that Emma induced a significant shift in sediment dynamics, causing retreat and erosion of the updrift shoal complex (with a net sediment volume loss of 2.40%), sediment transfer to the downdrift complex (that gained sediment volume of 0.32%), and channel rotation.. These changes contrast with the seaward growth of the shoal under mild conditions observed during non-extreme conditions, as between 2016 and 2017. The results highlight the importance that large extreme wave events can have on the morphodynamic evolution of ebb tidal deltas.
- Use of sub-pixel imagery classification to assess salt marsh plants’ adaptationPublication . Carrasco, Rita; Astori, Alexandra; Kombiadou, KaterinaThe inherent heterogeneity of coastal wetlands and the small size of halophytic plants present challenges in accurately sensing plant species, even with very high-resolution satellite imagery. This study used sub-pixel imagery classification methods on high spectral and spatial resolution imagery from Worldview-3 to predict plant species distribution in a mesotidal coastal wetland system. The predicted sub-pixel fractional abundance of plant species is discussed for three targeted wetland categories in the Ria Formosa lagoon: naturally evolving patches, patches modified by human activities, and patches affected by coastal squeeze. The Random Forest Regression algorithm was proven to be highly effective in unmixing the spectral signal of halophytic vegetation, enabling the retrieval of plant species distribution (7 plant species). To train the algorithm, field observations were used to classify satellite images. Differences in band feature importance for key species and bare soil were observed across the various sites. The comparison of species distribution between sites suggests that, in addition to biotic factors, other environmental influences likely affect ecological succession; therefore, large-scale mapping approaches based on remote sensing should be undertaken with caution. The results are important for understanding the diverse ecological behavior of marsh plants within the same system and highlight the variability in plant reflectance and the need for ground truthing when sensing plant cover from satellite data.
- Coastal dynamics in the Black Sea observed from optical and SAR satellite imagesPublication . Jiang, Dalin; Marino, Armando; Ionescu, Maria; Gvilava, Mamuka; Savaneli, Zura; Loureiro, Carlos; Spyrakos, Evangelos; Tyler, Andrew; Stanica, AdrianThis paper presents an overview of the approach developed to detect coastal dynamics by combining Synthetic Aperture Rader (SAR) and optical images. The method was developed with Sentinel-1 SAR and Sentinel-2 MSI images with a spatial resolution of 20 m, to detect the coastline changes in the Black Sea between 2016 and 2023. When compared with in situ measurements, the results showed that our approach provides reliable results with the rate of coastline change having a root mean square error of 1.73 m/year. In the Black Sea, around half the coastline changes are a result of natural process, and around 35% associated with coastal engineering. Natural coastline changes were mainly observed in deltaic areas, such as the Danube Delta. 91% of the artificial changes were found in the southern Black Sea coast on the Turkish coastline, and are a result of airport and harbour construction, and land reclamation activity. The results of this study can provide information on interventions that support the sustainable coastal zone management.
- Parameterised barrier morphological evolution for future storm impact assessmentPublication . Loureiro, Carlos; Horsburgh, Nicola; Ferreira, ÓscarCoastal storm impacts are mainly determined by the interaction of extreme water levels with barrier morphology, particularly the height of the foredune. While future projections of storm hydrodynamic forcing, integrating sea level rise, tides, waves and storm surges, are readily available, predicting future barrier morphology at a decadal scale remains a challenge due to uncertainties in modeling morphodynamic processes. This study proposes a simplified model to predict future foredune morphology at decadal scale and determine storm impacts on coastal barriers, focusing on the critical role of foredune morphology. The model identifies three morphological behavior modes based on the nature of the sediment budget and associated shoreline dynamics, distinguishing between: “keep-up mode” for accreting barriers, “catch-up mode” for stable to mildly accreting barriers, and “give-up mode” for eroding barriers. Application to the Portuguese coast, specifically the eroding barrier of Torrão do Lameiro, demonstrates that even with rising sea level and higher total water levels, storm impacts remain within the same regime by 2050. This simplified model offers a practical approach for considering an evolving foredune morphology, which can support first-order assessments of future storm impacts in changing climate.
- Sensing short-term adaptive cycles in mesotidal energetic beaches from satellite imageryPublication . Costas, Susana; Santos, Jacqueline; Doherty, Yarran; Splinter, Kristen D.; Serrão Bon de Sousa, Maria Luísa; Kombiadou, Katerina; Plomaritis, Theocharis; Taborda, RuiThe rapid development of approaches to automatically detect and extract shorelines from satellite imagery is revolutionizing the way we study coastal systems, offering deeper insights into their dynamic responses and adaptive capacities. This study evaluates the performance of the CoastSat toolkit in detect-ing shoreline retreat and recovery at Praia de Faro beach, South Portugal, following storm Emma in March 2018. The mesotidal, low-tide-terrace beach experienced significant erosion, with an average retreat of 20 m. PlanetScope imagery is used to assess shoreline detection accuracy, due to its higher temporal coverage com-pared to other open-access satellite constellations. This includes understanding the correspondence between the detected waterline and two water levels: the tide level and the instantaneous water level (combined effect of wave runup and tide). Linear water level corrections are applied to horizontally translate the detected water levels to a reference elevation that enables temporal comparisons. Results suggest that beach morphology strongly influences optimal correction approaches due to the type of beach response to storms, such as profile rotation. Under non-storm conditions, detected waterlines generally represent astronomic tide levels. While tide-level-based corrections improve accuracy during storms, runup-based corrections consistently outperform under non-storm conditions. Consequently, applying corrections that account for slope changes, runup levels during non-storm conditions, and tide level under storms enables the detection of storm impacts and recovery with an accuracy of approximately 6 m in Praia de Faro. These findings highlight the importance of tailoring detection methodologies to the morphological state of the beach as it evolves over time.
- Risk communication by coastal geoscientistsPublication . Matias, Ana; Pinto, Bruno; Carrasco, Rita; Areia, NeideStorms often harm coastal communities, a situation expected to worsen due to climate change and urban development. Effectively communicating with diverse audiences is thus critical for adapting to and attenuating increased coastal risks. This research focuses on risk communication by Coastal Geoscientists and Engineers, aiming to assess their perspectives and practices. The method used was an online questionnaire, with data collected in 2022–2023. The sample (n = 133) average age was 45, with slightly more men and mostly from Europe. About 95% of participants reported engaging in public communication, and most do coastal risk communication. Direct interaction with audiences such as public talks (74%) is preferred over indirect communication, and 79% had at least one annual contact with a journalist. Participants believe decision-makers should be more informed about risk location, frequency of occurrence, and how to engage citizens with coastal risk. However, this does not align with their top communication subject (coastal physical processes). Some significant differences were found in how gender, professional roles, and scientific backgrounds influence perceptions and priorities in coastal risk communication.
- Challenges in assessing longshore transport along the gulf of cadiz coast: insights from analysis of different wave data sourcesPublication . Santos, Jacqueline; Costas, Susana; Taborda, Rui; Garzon, Juan L.; Drago, TeresaEstimating coastal sediment budgets presents significant challenges due to the complex nature of coastline configurations and the often-bimodal wave regime. This study investigates longshore sediment transport (LST) along the Gulf of Cadiz by analyzing estimates obtained from various wave data sources and employing various approaches. The sensitivity of transport calculations to different wave data sources and approaches is evaluated, and the impact of easterly waves, or “Levante,” is examined for the different approaches. The nearshore wave regime was simulated using the SWAN model, with offshore conditions from ERA5 hindcast and the Faro buoy. Results were validated using observational data and LST was estimated using a deep water approximation of the CERC formula, extracting the net transport and the two components of the sediment transport: west-east and east-west. The results emphasize the critical importance of selecting appropriate forcing for applied models to simulate the nearshore wave regime and estimate sediment transport.