Present and future climate simulation of Mediterranean cyclones with a high resolution AOGCMs

Preliminary results are presented of a study aiming at producing a climatology of Mediterranean cyclones making use of a global AOGCM coupled with an interactive high-resolution model of the Mediterranean Sea. Cyclones are analyzed with both the lagrangian and the eulerian approaches, applied to three different simulations: a control one (present climate conditions) and two IPCC scenarios (A1B and A2). Both the North Atlantic stormtrack and cyclone track and genesis density statistics from the control dataset are analyzed compared to ERA40 reanalysis. Cyclones are grouped according to their genesis location and the corresponding lysis regions are identified. Partic- ular attention is devoted to the effects of sea-surface fields (temperature gradients and heat fluxes). The wet season (October–March) is examined in relation to the decrease in the intensity of cyclogenesis events in the region and trends are investigated

VISIR-I: Small vessels - Least-time nautical routes using wave forecasts

A new numerical model for the on-demand computation of optimal ship routes based on sea-state forecasts has been developed. The model, named VISIR (discoVerIng Safe and effIcient Routes) is designed to support decision-makers when planning a marine voyage. The first version of the system, VISIR-I, considers medium and small motor vessels with lengths of up to a few tens of metres and a displacement hull. The model is comprised of three components: a route optimization algorithm, a mechanical model of the ship, and a processor of the environmental fields. The optimization algorithm is based on a graph-search method with time-dependent edge weights. The algorithm is also able to compute a voluntary ship speed reduction. The ship model accounts for calm water and added wave resistance by making use of just the principal particulars of the vessel as input parameters. It also checks the optimal route for parametric roll, pure loss of stability, and surfriding/broaching-to hazard conditions. The processor of the environmental fields employs significant wave height, wave spectrum peak period, and wave direction forecast fields as input. The topological issues of coastal navigation (islands, peninsulas, narrow passages) are addressed. Examples of VISIR-I routes in the Mediterranean Sea are provided. The optimal route may be longer in terms of miles sailed and yet it is faster and safer than the geodetic route between the same departure and arrival locations. Time savings up to 2.7% and route lengthening up to 3.2% are found for the case studies analysed. However, there is no upper bound for the magnitude of the changes of such route metrics, which especially in case of extreme sea states can be much greater. Route diversions result from the safety constraints and the fact that the algorithm takes into account the full temporal evolution and spatial variability of the environmental fields

Coastal ocean forecasting with an unstructured grid model in the southern Adriatic and northern Ionian seas

Abstract. SANIFS (Southern Adriatic Northern Ionian coastal Forecasting System) is a coastal-ocean operational system based on the unstructured grid finite-element three-dimensional hydrodynamic SHYFEM model, providing short-term forecasts. The operational chain is based on a downscaling approach starting from the large-scale system for the entire Mediterranean Basin (MFS, Mediterranean Forecasting System), which provides initial and boundary condition fields to the nested system. The model is configured to provide hydrodynamics and active tracer forecasts both in open ocean and coastal waters of southeastern Italy using a variable horizontal resolution from the open sea (3–4 km) to coastal areas (50–500 m). Given that the coastal fields are driven by a combination of both local (also known as coastal) and deep-ocean forcings propagating along the shelf, the performance of SANIFS was verified both in forecast and simulation mode, first (i) on the large and shelf-coastal scales by comparing with a large-scale survey CTD (conductivity–temperature–depth) in the Gulf of Taranto and then (ii) on the coastal-harbour scale (Mar Grande of Taranto) by comparison with CTD, ADCP (acoustic doppler current profiler) and tide gauge data. Sensitivity tests were performed on initialization conditions (mainly focused on spin-up procedures) and on surface boundary conditions by assessing the reliability of two alternative datasets at different horizontal resolution (12.5 and 6.5 km). The SANIFS forecasts at a lead time of 1 day were compared with the MFS forecasts, highlighting that SANIFS is able to retain the large-scale dynamics of MFS. The large-scale dynamics of MFS are correctly propagated to the shelf-coastal scale, improving the forecast accuracy (+17 % for temperature and +6 % for salinity compared to MFS). Moreover, the added value of SANIFS was assessed on the coastal-harbour scale, which is not covered by the coarse resolution of MFS, where the fields forecasted by SANIFS reproduced the observations well (temperature RMSE equal to 0.11 °C). Furthermore, SANIFS simulations were compared with hourly time series of temperature, sea level and velocity measured on the coastal-harbour scale, showing a good agreement. Simulations in the Gulf of Taranto described a circulation mainly characterized by an anticyclonic gyre with the presence of cyclonic vortexes in shelf-coastal areas. A surface water inflow from the open sea to Mar Grande characterizes the coastal-harbour scale

Coupling hydrodynamic and wave models: first step and sensitivity experiments in the Mediterranean Sea

This work describes the first step towards a fully coupled modelling system composed of an ocean circulation and a wind wave model. Sensitivity experiments are presented for the Mediterranean Sea where the hydrodynamic model NEMO is coupled with the third-generation wave model WaveWatchIII (WW3). Both models are implemented at 1/16° horizontal resolution and are forced by ECMWF 1/4° horizontal resolution atmospheric fields. The models are two-way coupled at hourly intervals exchanging the following fields: sea surface currents and temperature are transferred from NEMO to WW3 by modifying the mean momentum transfer of waves and the wind speed stability parameter, respectively. The neutral drag coefficient computed by WW3 is then passed to NEMO, which computes the surface stress. Five-year (2009–2013) numerical experiments were carried out in both uncoupled and coupled mode. In order to validate the modelling system, numerical results were compared with coastal and drifting buoys and remote sensing data. The results show that the coupling of currents with waves improves the representation of the wave spectrum. However, the wave-induced drag coefficient shows only minor improvements in NEMO circulation fields, such as temperature, salinity, and currents

EEG-based outcome prediction after cardiac arrest with convolutional neural networks: Performance and visualization of discriminative features.

Prognostication for comatose patients after cardiac arrest is a difficult but essential task. Currently, visual interpretation of electroencephalogram (EEG) is one of the main modality used in outcome prediction. There is a growing interest in computer-assisted EEG interpretation, either to overcome the possible subjectivity of visual interpretation, or to identify complex features of the EEG signal. We used a one-dimensional convolutional neural network (CNN) to predict functional outcome based on 19-channel-EEG recorded from 267 adult comatose patients during targeted temperature management after CA. The area under the receiver operating characteristic curve (AUC) on the test set was 0.885. Interestingly, model architecture and fine-tuning only played a marginal role in classification performance. We then used gradient-weighted class activation mapping (Grad-CAM) as visualization technique to identify which EEG features were used by the network to classify an EEG epoch as favorable or unfavorable outcome, and also to understand failures of the network. Grad-CAM showed that the network relied on similar features than classical visual analysis for predicting unfavorable outcome (suppressed background, epileptiform transients). This study confirms that CNNs are promising models for EEG-based prognostication in comatose patients, and that Grad-CAM can provide explanation for the models' decision-making, which is of utmost importance for future use of deep learning models in a clinical setting

Jadranski prognostički sustav

A regional ocean forecasting system has been implemented in the framework of the ADRIatic sea integrated COastal areaS and river basin Management system Pilot Project (ADRICOSM). The system is composed of a 5 km horizontal resolution model and an observing system collecting coastal and open ocean hydrological data. The numerical model is based on the Princeton Ocean Model using a SMOLARKIEWICZ iterative advection scheme, interactive air-sea flux computation, Po and other Adriatic rivers flow rates and is one-way nested to a general circulation model of the Mediterranean Sea. In this study the data from the observing system are used only for model validation. The results of the first operational year are shown and the model performance has been assessed based on root mean square (RMS) criteria.U okviru projekta “Integralno upravljanje obalnom zonom Jadranskog mora (ADRICOSM)” uspostavljen je regionalni oceanografski prognostički sustav. Sustav se sastoji od oceanografskog modela horizontalne rezolucije 5 km i sustava prikupljanja hidrografskih podataka u priobalnom području i na otvorenom moru. Numerički model je temeljen na Princetonskom Oceanskom Modelu (POM) uz korištenje iterativne SMO-LARKIEWICZ-eve advekcijske sheme, interaktivnog računanja protoka na granici mora i atmosfere, protoka rijeke Po, kao i drugih jadranskih rijeka, te gniježđenja s mediteranskim modelom. U ovom radu podaci iz sustava mjerenja korišteni su samo za ocjenu rezultata modela. Prikazani su rezultati dobiveni tijekom prve godine operativnog sustava, a procjena ponašanja modela i njegovih rezultata dobivena je na temelju RMS (root mean square) pogreške

Climate variability and change in the Euro-Mediterranean Region: results from a global AOGCM coupled with an interactive high-resolution model of the Mediterranean Sea

In this work we present and discuss the results obtained from a set of present and future climate simulations performed with a high-resolution model able to represent the dynamics of the Mediterranean Sea. The ability of the model to reproduce the basic features of the observed climate in the Mediterranean region and the beneficial effects of both atmospheric improved resolution and interactive Mediterranean Sea are assessed. In particular, the major characteristics of the variability in the Mediterranean basin and its connection with the large-scale circulation are investigated. Furthermore, the mechanisms through which global warming might affect the regional features of the climate are explored, focusing especially on the characteristics of the hydrological cycle

EFFECTS OF TROPICAL CYCLONES ON OCEAN HEAT TRANSPORT AS SIMULATED BY A HIGH RESOLUTION COUPLED GENERAL CIRCULATION MODEL

In this study the interplay between Tropical Cyclones (TCs) and the Northern hemispheric Ocean Heat Transport (OHT) is investigated. In particular, results from a numerical simulation of the 20th and 21st Century climate, following the Intergovernmental Panel for Climate Change (IPCC) 20C3M and A1B scenario protocols respectively have been analyzed. The numerical simulations have been performed using a state-of-the-art global atmosphere-ocean-sea-ice coupled general circulation model - CGCM (CMCC-MED, Gualdi et al. 2010, Scoccimarro et al. 2010) with relatively high-resolution (T159) in the atmosphere. The model is an evolution of the INGV-SXG (Gualdi et al. 2008, Bellucci et al. 2008) and the ECHAM-OPA-LIM (Fogli et al. 2009, Vichi et al. 2010) The simulated TCs exhibit realistic structure, geographical distribution (Fig.2) and interannual variability, indicating that the model is able to capture the basic mechanisms linking the TC activity with the large scale circulation. The cooling of the surface ocean observed in correspondence of the TCs is well simulated by the model (Fig.3). TC activity is shown to significantly affect the poleward OHT out of the tropics, and the heat transport into the deep tropics (Fig.4). This effect, investigated by looking at the 100 most intense Northern Hemisphere TCs, is strongly correlated with the TC-induced momentum flux at the ocean surface (Fig.7). TCs frequency and intensity appear to be substantially stationary through the whole 1950-2069 simulated period as well as the effect of the TCs on the meridional OHT

Mediterranean Sea large-scale low-frequency ocean variability and water mass formation rates from 1987 to 2007: A retrospective analysis

We describe a synthesis of the Mediterranean Sea circulation structure and dynamics from a 23-year- long reanalysis of the ocean circulation carried out by Adani et al. (2011). This mesoscale permitting dynamical reconstruction of past ocean variability in the Mediterranean Sea allows the study of the time-mean circulation and its low frequency, decadal, components. It is found that the time-mean circu- lation is composed of boundary and open ocean intensified jets at the border of cyclonic and anticyclonic gyres. The large scale basin circulation is generally characterized in the northern regions by cyclonic gyres and in its southern parts by anticyclonic gyres and eddy-dominated flow fields, with the exception of the Tyrrhenian and the northern Ionian Sea. The time-mean Tyrrhenian Sea circulation is dominated by cyclonic gyres of different intensity and intermittency. The northern Ionian Sea circulation, however, reverses in sign in two ten-year periods, the first in 1987–1996 and the second in 1997–2006, which is here called the Northern Ionian reversal phenomenon. This reversal is provoked by the excursion of the Atlantic-Ionian Stream from the middle to the northern parts of the basin. The decadal variability of other parts of the basin is characterized by changes in strength of the basin scale structures. The water mass formation rates and variability are dominated by event-like periods where the intermediate and deep waters are formed for 2–3 years at higher rates. The largest deep water formation events of the past 23 years occurred separately in the western and eastern Mediterranean basin: the first coincided with the Eastern Mediterranean Transient (Roether et al., 1996) and the second with the western Mediterranean deep water formation event in 2005–2006 (Smith et al., 2008). A new schematic of the basin-scale circu- lation is formulated and commented.Published318-3324A. Oceanografia e climaJCR Journa

MyOcean Scientific Validation Report (ScVR) for WP9 – Med-MFC

This report was written for MyOcean ProjectPublished4.6. Oceanografia operativa per la valutazione dei rischi in aree marinereserve