Giovanni Quattrocchi

Predicting future thermal habitat suitability of competing native and invasive fish species: From metabolic scope to oceanographic modelling

Global increase in sea temperatures has been suggested to facilitate the incoming and spread of tropical invaders. Here, we determined the effect of temperature on the aerobic metabolic scope of two competing fish species, one native and one invasive, and we predicted their future thermal habitat suitability.

Assessment of oil slick hazard and risk at vulnerable coastal sites.

This work gives an assessment of the hazard faced by Sicily coasts regarding potential offshore surface oil spill events and provides a risk assessment for Sites of Community Importance (SCI) and Special Protection Areas (SPA). A lagrangian module, coupled with a high resolution finite element three dimensional hydrodynamic model, was used to track the ensemble of a large number of surface trajectories followed by particles released over 6 selected areas located inside the Sicily Channel. The analysis was carried out under multiple scenarios of meteorological conditions. Oil evaporation, oil weathering, and shore stranding are also considered. Seasonal hazard maps for different stranding times and seasonal risk maps were then produced for the whole Sicilian coastline. The results highlight that depending on the meteo-marine conditions, particles can reach different areas of the Sicily coast, including its northern side, and illustrate how impacts can be greatly reduced through prompt implementation of mitigation strategies.

Morphological changes of a Mediterranean beach over one year (San Giovanni Sinis, western Mediterranean)

ABSTRACT Simeone, S., De Falco, G., Quattrocchi, G., Cucco, A. 2014. Morphological changes of an Mediterranean beach over one year (San Giovanni Sinis, western Mediterranean).In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 217–222, ISSN 0749-0208. Mediterranean beaches experience major modifications in their morphology and grain size features mainly during intense storms and extreme meteo-marine events. The assessment of beach response to storms can be useful in the evaluation of coastal hazards, and in relation to the efficiency of management projects such as artificial nourishment. This paper aims to establish the subaerial morphological response of a beach located in western Sardinia (western Mediterranean) during the period of a year. Both experimental and numerical approaches were adopted to investigate the beach system. In particular, beach profiles, acquired by means of Differential Positioning System were used to analyze the morphological changes of the beach and wave parameters and current velocity data were collected by means of an Acoustic wave and current meter (ADCP). Numerical techniques were also applied to investigate the hydrodynamics in the area of study. Coupled wind wave - 3D hydrodynamic finite element model were used to reproduce the wave propagation and the wind, tide and wave induced 3D water circulation along the coastal areas, and it displayed a good accuracy. During the year, the beach experienced intense morphological changes in the area where submerged beach is not occupied by rocky outcrops and the model was also able to reproduce the related observed periods of strong wind wave events. The interdisciplinary approach allowed an evaluation to be made about the response of the beach morphology in respect to meteo-marine forcings.

Optimal design of a Lagrangian observing system for hydrodynamic surveys

ABSTRACT In this paper the problem of the optimisation of at-sea campaigns is tackled throughout the implementation of a near real-time decision support system (DSS) for short-term Lagrangian observing platforms. The DSS consisted of two modules: a real-time coastal-ocean forecasting system (CFS), including both hydrodynamic and particle-tracking numerical models, and a module to provide optimised deployment solutions for a set of Lagrangian current-meter buoys. The system was calibrated for a shallow water environment – the Cabras Lagoon in the western Mediterranean Sea. The DSS was then applied to provide in situ optimised measurement strategies during a Lagrangian survey campaign. The different solutions provided by the DSS were verified by real-time measurements and the system was established to be efficient in reducing the cost–benefit ratio and favouring long records and near-synoptic and non-redundant observations.

Wind Fields From C- and X-Band SAR Images at VV Polarization in Coastal Area (Gulf of Oristano, Italy)

This work deals with the spatial characteristics of the wind fields evaluated from synthetic aperture radar (SAR) images and simulated by the weather research and forecasting (WRF) atmospheric model in the Gulf of Oristano, a small coastal area about 10 km × 18 km wide in western coast of Sardinia (Western Mediterranean Sea). The SARderived wind fields have been obtained analyzing images of the COSMO-SkyMed, Radarsat-2, and Sentinel-1A satellites through a fully two-dimensional continuous wavelet transform (2-D-CWT) method. The analysis of the wind directions has shown that the model variability is limited if compared to that inferred by 2-D-CWT method, which mostly respects the variability evidenced by in situ data. As the use of model directions to compute the SAR wind fields is a standard in many studies, the impact on the SAR wind speed retrieval of using the model instead of the SARderived directions has been assessed: differences of wind speed greater than ±10% occur for about the 20% of data. The spatial variability of the SAR and model wind speed fields results quite different at both local and domain scales. The knowledge of the spatial variations of the surface wind fields can be very important for the oceanographic applications and constitutes the added value brought by SAR in the description of the coastal wind. For this reason, the SAR-derived wind fields should be taken as reference in many kind of applications.

The wind-measuring system in the Gulf of Oristano: a support for coastal-scale oceanographic applications

ABSTRACT This paper describes a wind-measuring system (WMS) in the coastal area of the Gulf of Oristano, Sardinia, Italy. In this area, an oceanographic forecasting system based on a high-resolution finite-element hydrodynamic and wave model is operative. The system is forced by the wind fields provided by medium resolution (about 0.1×0.1 deg) atmospheric models. The high spatial resolution of the oceanographic prediction system (between 50 m and 1 km) is not accompanied by a similar resolution for atmospheric forcing. Therefore, the implementation of a WMS, aimed at accurately measuring the three-dimensional wind components, provides an essential tool to evaluate both the performance of the atmospheric models used to force the oceanographic models and the sensitivity of the oceanographic models to wind forcing of different qualities and spatial resolutions, the experimental fields included. This paper describes the WMS, the data collected and the geophysical quantities obtained from the time series of the three components of the wind sampled at high frequency. It also shows the results of comparisons between the experimental wind data and those from the atmospheric model at present used to force the oceanographic forecasting system. The information obtained from the WMS is unique, spanning from the spatial and temporal variability of the wind over the area of investigation to the evaluation of the basic quantities characterising the atmospheric boundary layer.

Predictability of wind‐induced sea surface transport in coastal areas

In this work we investigated the predictability of the wind-induced sea surface transport in coastal areas. The wind fields predicted by two state-of-the-art meteorological models, namely ECMWF and SKIRON, were used as forcing for a hydrodynamic and particle-tracking model applied to reproduce a set of observed drifters trajectories in a coastal area of the Mediterranean Sea. A set of anemometric data derived by in situ measurements were also adopted as model forcing to reproduce the observed drifter paths. This approach provided a baseline that was used as a reference for evaluating the effects of the predicted wind accuracy on the numerical model solution. The accuracy of the simulation results obtained using, as model forcing, the observed wind data was fair and suitable for most of the operational oceanographic purposes. It decreased when using the wind data predicted by the two meteorological models. In particular, the results obtained using ECMWF data were about 3 times more accurate than the ones obtained using SKIRON ones. The uncertainties were strongly dependent on the range of observed wind speed classes with a different behavior depending on the type of adopted wind data. Finally, the amplification of the errors in predicting the sea surface transport generated by the inaccuracies of the predicted wind fields was quantified.

Beaches Morphological Variability Along a Complex Coastline (Sinis Peninsula, western Mediterranean Sea).

ABSTRACT Simeone, S., De Falco, G., Quattrocchi, G., Palombo, L., Cucco, A. 2016. Beaches morphological variability along a complex coastline (Sinis Peninsula, western Mediterranean Sea). In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1302 - 1306. Coconut Creek (Florida), ISSN 0749-0208. Wave climate, sediments, topographic features and tides influence the morphology and the short-term dynamics of beaches. The interactions between these different forcings affect the features of the beach system. In this work the morphological beach responses in relation to the most energetic period of the year were studied in a coastline with high geomorphological complexity. Three beaches, located along the Sinis Peninsula (western Mediterranean Sea, western Sardinia), were monitored for about 6 months. In order to estimate morphological changes, repetitive beach profiles were acquired by means of Differential Global Positioning System. Wave data were collected by an offshore wave buoy and the grainsize features of each beach was determined. A coupled 3D hydrodynamics–wave, finite element model was also applied in order to investigate the current dynamics and the wave propagation along the selected coastal area. During the monitoring period, the beaches experienced relevant changes when consecutive storms occurred. In sediment deprived embayed beaches, the presence of headlands interacting with waves, favored beach rotation and lead to a crenulate shape of the shoreline. In addition, on sediment abundant beach, cross-shore sediment transport and simultaneous shoreline retreats were observed during storms events. Finally, the effects on the wave heights and directions, due complex coastline features of the Sinis Peninsula, were discussed in relation to the morphodynamics response of each beach.

M2, overtides and compound tides generation in the Strait of Messina: the response of a non-hydrostatic, finite-element ocean model

ABSTRACT Quattrocchi, A.; Gorman, J.G., Piggott M.D. and Cucco, A., 2016. M2, overtides and compound tides generation in the Strait of Messina: the response of a non-hydrostatic, finite-element ocean model. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 657–661. Coconut Creek (Florida), ISSN 0749-0208. The nonlinear interactions between the main tidal constituents and geographical constraints are investigated using Fluidity-ICOM, a non-hydrostatic finite-element ocean model that was implemented in the region of the Strait of Messina (Mediterranean Sea). As a first crucial approach, the barotropic tidal dynamics was investigated and the model solution was interpreted in terms of tidal maps and spectra obtained by harmonic analysis of the sea surface elevation. The model domain is represented by an unstructured mesh with variable spatial resolution ranging from two kilometres to fifty meters, in order to resolve the shoreline in the inner part of the Strait. Amplitudes and phases of the main diurnal and semidiurnal tides were prescribed at the off-shore open boundaries. A calibration procedure was carried out with available observations in order to provide a suitable parameterization for bottom drag coefficient and horizontal viscosities. The results gave clear indication that over-harmonics and compound tides are generated in the Strait. The generation mechanism, geographical localization and intensity of these phenomena were described to provide groundwork for further model analyses that would clarify the role of shallow water tides in modifying the hydrological setup in proximity of sea straits.

Wind fields from COSMO-SkyMed and RADARSAT-2 SAR in coastal areas

This paper is aimed to outline the possible uses of SAR derived wind fields in coastal meteorology, taking advantage of two running projects: the first of meteorological flavor, aimed to measure and reproduce the surface wind field in a small coastal area; the second to investigate the possibilities offered by the combined use of simultaneous COSMO-SkyMed and RADARSAT-2 SAR images in the description of the wind field in the same area. The main issues faced in this study and partially solved are: the development of a suitable methodology to extract the wind field from SAR images at different bands, polarization, incidence angle; the understanding of the potentialities of the SAR derived winds to catch the patterns of the spatial variability of the wind over the coastal area; the assessment of the SAR derived wind from comparisons with the simultaneous experimental data. Of course, the results presented here are not exhaustive, but only aim to track the ongoing research on the topic of wind over local coastal areas.