A changing wave climate in the Mediterranean Sea during 58-years using UERRA-MESCAN-SURFEX high-resolution wind fields

This study unravels 58-years (1961-2018) of wind-waves in the Mediterranean Sea (MS). A wave dataset was developed using the wave model WAVEWATCH III forced with the high-resolution (5.5 km) UERRA-MESCAN-SURFEX downscaled wind fields which better contain the imprint of the local geomorphology compared to other, coarser wind datasets used in previous studies. Thus, improving the reliability and characterization of the wind-wave climate in the basin. Validation results revealed a higher performance than previous datasets, particularly on the wave direction (θm), with a bias<1º. Climate variability at seasonal and interannual scales, wind-seas and swells distribution, and long-term trends in storminess and in the mean and extreme regimes were analysed. Results show a slight swell influence over the wind-sea in the hourly spectra at a large portion of the basin, excluding the wave generation areas. We detected that the western MS is the most storminess region with an average of three storms/year. Moreover, the anomalies of the seasonal mean wave direction relative to θm are large (~60º), with opposing behaviours between the winter and summer. Finally, the long-term trends in the mean and extreme conditions and in storminess are mild with values reaching 6 cm/decade and less than 2% in the absolute value, respectively

Controls of Multimodal Wave Conditions in a Complex Coastal Setting

Coastal hazards emerge from the combined effect of wave conditions and sea level anomalies associated with storms or low-frequency atmosphere-ocean oscillations. Rigorous characterization of wave climate is limited by the availability of spectral wave observations, the computational cost of dynamical simulations, and the ability to link wave-generating atmospheric patterns with coastal conditions. We present a hybrid statistical-dynamical approach to simulating nearshore wave climate in complex coastal settings, demonstrated in the Southern California Bight, where waves arriving from distant, disparate locations are refracted over complex bathymetry and shadowed by offshore islands. Contributions of wave families and large-scale atmospheric drivers to nearshore wave energy flux are analyzed. Results highlight the variability of influences controlling wave conditions along neighboring coastlines. The universal method demonstrated here can be applied to complex coastal settings worldwide, facilitating analysis of the effects of climate change on nearshore wave climate.This work was funded by the U.S. Geological Survey (USGS) Coastal and Marine Geology Program. The authors thank Jorge Perez, IH Cantabria, for providing the GOW wave hindcast and for assistance with wave spectra, and Sean Vitousek, University of Chicago, for a helpful review. This material is based upon work supported by the U.S. Geological Survey under grant/cooperative agreement GI5AC00426. A. R., J. A. A. A., and F. J. M. acknowledge the support of the Spanish “Ministerio de Economía y Competitividad” under grant BIA2014-59643-R. J. A. A. A. was funded by the Spanish “Ministerio de Educación, Cultura y Deporte” FPU (Formación del Profesorado Universitario) studentship BOE-A-2013-12235. Reanalyses of ocean data are available for research purposes through IH Cantabria (contact [email protected]). Southern California Bight look-up table data are available at https://doi.org/10.1594/PANGAEA.880314. Related Southern California nearshore wave data can be found at http://dx.doi.org/10.5066/F7N29V2V

A multiscale climate emulator for long-term morphodynamics (MUSCLE-morpho)

Interest in understanding long-term coastal morphodynamics has recently increased as climate change impacts become perceptible and accelerated. Multiscale, behavior-oriented and process-based models, or hybrids of the two, are typically applied with deterministic approaches which require considerable computational effort. In order to reduce the computational cost of modeling large spatial and temporal scales, input reduction and morphological acceleration techniques have been developed. Here we introduce a general framework for reducing dimensionality of wave-driver inputs to morphodynamic models. The proposed framework seeks to account for dependencies with global atmospheric circulation fields and deals simultaneously with seasonality, interannual variability, long-term trends, and autocorrelation of wave height, wave period, and wave direction. The model is also able to reproduce future wave climate time series accounting for possible changes in the global climate system. An application of long-term shoreline evolution is presented by comparing the performance of the real and the simulated wave climate using a one-line model

Un modelo empírico para la estimación del oleaje producido por ciclones tropicales a partir de datos de satélite

Se agradece la financiación del proyecto BIA2014-59643-R del Ministerio de Economía y Competitividad

Respuesta morfodinámica litoral debida a la evolución climática

RESUMEN: Esta tesis propone nuevas metodologías y modelos para la evaluación de los impactos en el sistema costero integrando diferentes escalas espaciales y temporales de variabilidad en respuesta a variaciones climáticas a escala regional (cuenca oceánica). En primer lugar, presentamos un marco general para simular y reducir la dimensionalidad de los forzamientos de oleaje para su uso en modelos morfodinámicos teniendo en cuenta la variabilidad climática. A continuación, definimos un nuevo modelo de ``downscaling estadístico'' para estimar el clima de oleaje a partir de campos de presión atmosférica a nivel del mar, teniendo en cuenta la relación espacio-temporal y, por lo tanto, representando las familias de oleaje. Después, proponemos una metodología híbrida para proyectar la variabilidad climática observada (o futura) a nivel regional en el clima de oleaje local y con ello en la respuesta asociada del sistema costero, e investigamos los cambios en las formas de gran escala presentes en la costa de North y South Carolina (EE.UU.) desde 1870 hasta la actualidad. Finalmente, presentamos un modelo de evolución de línea de costa y erosión de duna teniendo en cuenta procesos longitudinales y de perfil en múltiples escalas de variabilidad temporal, incorporando el efecto del oleaje y el nivel del mar.ABSTRACT: This thesis proposes new methodologies and models for coastal hazard assessment integrating several spatial and temporal scales of variability in response to climate shifts at ocean-basin-scale. First, we introduce a general framework for simulating and reducing dimensionality of wave-driver inputs to morphodynamic models accounting for the climate variability. Next, we define a statistical downscaling model of atmospheric fields to local wave conditions tracking the spatiotemporal relationship and thus accounting for the wave families. Then, we propose a computationally efficient way (combining statistical, data mining and dynamic modeling techniques) to downscale from ocean-basin-scale meteorological climate to the nearshore wave and wind climate affecting any particular coastline, and we investigate shifts in the Carolina's (USA) coastline shape since 1870. Finally, we present a shoreline change - dune erosion model for coastal planning and adaptation accounting for coupled longshore and crosshore processes at different time scales, including seasonal, sequencing and clustering of storm events, and interannual and decadal oscillations of various sorts by incorporating the effects of integrated varying wave action and water levels