Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Storm identification for high-energy wave climates as a tool to improve long-term analysisPublication . Kümmerer, Vincent; Ferreira, Óscar; Fanti, Valeria; Loureiro, C.Coastal storms can cause erosion and flooding of coastal areas, often accompanied by significant social-economic disruption. As such, storm characterisation is crucial for an improved understanding of storm impacts and thus for coastal management. However, storm definitions are commonly different between authors, and storm thresholds are often selected arbitrarily, with the statistical and meteorological independence between storm events frequently being neglected. In this work, a storm identification algorithm based on statistically defined criteria was developed to identify independent storms in time series of significant wave height for high wave energy environments. This approach proposes a minimum duration between storms determined using the extremal index. The performance of the storm identification algorithm was tested against the commonly used peak-over-threshold. Both approaches were applied to 40 and 70-year-long calibrated wave reanalyses datasets for Western Scotland, where the intense and rapid succession of extratropical storms during the winter makes the identification of independent storm events notably challenging. The storm identification algorithm provides results that are consistent with regional meteorological processes and timescales, allowing to separate independent storms during periods of rapid storm succession, enabling an objective and robust storm characterisation. Identifying storms and their characteristics using the proposed algorithm allowed to determine a statistically significant increasing long-term trend in storm duration, which contributes to the increase in storm wave power in the west of Scotland. The coastal storm identification algorithm is found to be particularly suitable for high-energy, storm-dominated coastal environments, such as those located along the main global extratropical storm tracks.
- Development of topo-bathymetric continuum profiles for coastal barriers with global open-access dataPublication . Fanti, Valeria; Loureiro, Carlos; Ferreira, ÓscarCoastal barriers are dynamic and vulnerable coastal environments exposed to storms and rising sea levels, requiring a thorough understanding of their physical and geomorphological characteristics. Despite this, high-resolution topo-bathymetric data are not openly available for most of the world's coastal areas, preventing accurate estimation of the exposure to storms and associated risks. Global models of topography and bathymetry, derived from remote sensing techniques, are available worldwide as an open-source solution to characterise coastal morphology. However, their coarse resolution, limited vertical and horizontal accuracy, alongside inconsistencies in the transition from land to the shallow nearshore zone, make their use in coastal areas challenging, requiring careful evaluation. This study investigates the potential and limitations of four recent open-access satellite-derived topographic models (Copernicus GLO-30 DEM, AW3D30, TanDEMX, Euro-Maps 3D) and three bathymetric models (GEBCO_2023, SRTM15+, ETOPO 2022) in five coastal barriers. It proposes a new approach to integrate global models to provide a consistent representation of the topo-bathymetric continuum profile in coastal areas characterised by a barrier morphology. Coastal barrier profiles, representative of natural sectors and characterized by morphological homogeneity, were derived by merging global topographic and bathymetric digital elevation models and implementing an equilibrium profile in the transition zone. The profiles obtained from the global models were compared with higher resolution local or regional topo-bathymetry. The global topographies tend to underestimate the dune top, with TanDEM-X giving the best results in terms of dune crest height and beach slope. The barrier continuum profiles that merged TanDEM-x and ETOPO 2022 global models were found to have the lowest error, with a vertical RMSE of 0.76 m. Based on integration of these remotely sensed models, it is possible to determine average representative coastal barrier profiles suitable for use in global to regional coastal studies or in data-poor areas, potentially serving as a cost-effective tool for preliminary coastal hazard assessments and early warning systems at wide spatial scales.