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Viola F.,Consorzio Interuniversitario Nazionale per la Fisica Delle Atmosfere e Delle Idrosfere | Noto L.V.,Consorzio Interuniversitario Nazionale per la Fisica Delle Atmosfere e Delle Idrosfere | La Loggia G.,Consorzio Interuniversitario Nazionale per la Fisica Delle Atmosfere e Delle Idrosfere
Hydrology and Earth System Sciences | Year: 2013

Changes in rainfall characteristics are one of the most relevant signs of current climate alterations.Many studies have demonstrated an increase in rainfall intensity and a reduction of frequency in several areas of the world, including Mediterranean areas. Rainfall characteristics may be crucial for vegetation patterns formation and evolution in Mediterranean ecosystems, with important implications, for example, in vegetation water stress or coexistence and competition dynamics. At the same time, characteristics of extreme rainfall events are fundamental for the estimation of flood peaks and quantiles that can be used in many hydrological applications, such as design of the most common hydraulic structures, or planning and management of floodprone areas. In the past, Sicily has been screened for several signals of possible climate change. Annual, seasonal and monthly rainfall data in the entire Sicilian region have been analyzed, showing a global reduction of total annual rainfall. Moreover, annual maximum rainfall series for different durations have been rarely analyzed in order to detect the presence of trends. Results indicated that for short durations, historical series generally exhibit increasing trends, while for longer durations the trends are mainly negative. Starting from these premises, the aim of this study is to investigate and quantify changes in rainfall statistics in Sicily, during the second half of the last century. Time series of about 60 stations over the region have been processed and screened by using the nonparametric Mann-Kendall test. In particular, extreme events have been analyzed using annual maximum rainfall series at 1, 3, 6, 12 and 24 h duration, while daily rainfall properties have been analyzed in terms of frequency and intensity, also characterizing seasonal rainfall features. Results of extreme events analysis confirmed an increasing trend for rainfall of short durations, especially for 1 h rainfall duration. Conversely, precipitation events of long durations have exhibited a decreased trend. Increase in shortduration precipitation has been observed especially in stations located along the coastline; however, no clear and welldefined spatial pattern has been outlined by the results. Outcomes of analysis for daily rainfall properties have showed that heavy-torrential precipitation events tend to be more frequent at regional scale, while light rainfall events exhibited a negative trend at some sites. Values of total annual precipitation events confirmed a significant negative trend, mainly due to the reduction during the winter season. © Author(s) 2013.


Mascaro G.,Arizona State University | Mascaro G.,University of Cagliari | Mascaro G.,Consorzio Interuniversitario Nazionale per la Fisica Delle Atmosfere e Delle Idrosfere | Piras M.,University of Cagliari | And 4 more authors.
Hydrology and Earth System Sciences | Year: 2013

The water resources and hydrologic extremes in Mediterranean basins are heavily influenced by climate variability. Modeling these watersheds is difficult due to the complex nature of the hydrologic response as well as the sparseness of hydrometeorological observations. In this work, we present a strategy to calibrate a distributed hydrologic model, known as TIN-based Real-time Integrated Basin Simulator (tRIBS), in the Rio Mannu basin (RMB), a medium-sized watershed (472.5 km2) located in an agricultural area in Sardinia, Italy. In the RMB, precipitation, streamflow and meteorological data were collected within different historical periods and at diverse temporal resolutions. We designed two statistical tools for downscaling precipitation and potential evapotranspiration data to create the hourly, high-resolution forcing for the hydrologic model from daily records. Despite the presence of several sources of uncertainty in the observations and model parameterization, the use of the disaggregated forcing led to good calibration and validation performances for the tRIBS model, when daily discharge observations were available. The methodology proposed here can be also used to disaggregate outputs of climate models and conduct high-resolution hydrologic simulations with the goal of quantifying the impacts of climate change on water resources and the frequency of hydrologic extremes within medium-sized basins. © Author(s) 2013.


Majone B.,University of Trento | Villa F.,University of Trento | Deidda R.,University of Cagliari | Deidda R.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | Bellin A.,University of Trento
Science of the Total Environment | Year: 2015

Climate change is expected to cause alterations of streamflow regimes in the Alpine region, with possible relevant consequences for several socio-economic sectors including hydropower production. The impact of climate change on water resources and hydropower production is evaluated with reference to the Noce catchment, which is located in the Southeastern Alps, Italy. Projected changes of precipitation and temperature, derived from an ensemble of 4 climate model (CM) runs for the period 2040-2070 under the SRES A1B emission scenario, have been downscaled and bias corrected before using them as climatic forcing in a hydrological model. Projections indicate an increase of the mean temperature of the catchment in the range 2-4. K, depending on the climate model used. Projections of precipitation indicate an increase of annual precipitation in the range between 2% and 6% with larger changes in winter and autumn. Hydrological simulations show an increase of water yield during the period 2040-2070 with respect to 1970-2000. Furthermore, a transition from glacio-nival to nival regime is projected for the catchment. Hydrological regime is expected to change as a consequence of less winter precipitation falling as snow and anticipated melting in spring, with the runoff peak decreasing in intensity and anticipating from July to June. Changes in water availability reflect in the Technical Hydropower Potential (THP) of the catchment, with larger changes projected for the hydropower plants located at the highest altitudes. Finally, the impacts on THP of water use policies such as the introduction of prescriptions for minimum ecological flow (MEF) have been analyzed. Simulations indicate that in the lower part of the catchment reduction of the hydropower production due to MEF releases from the storage reservoirs counterbalances the benefits associated to the projected increases of inflows as foreseen by simulations driven only by climate change. © 2015 Elsevier B.V.


Coria C.A.N.,University of Camerino | Coria C.A.N.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | Tesei L.,University of Camerino | Tesei L.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | And 4 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

DISPAS is an agent-based simulator for fish stock assessment developed as a decision making support for the sustainable management of fishery. In this work we enlarge the underlying model of DISPAS allowing it to model and simulate a multi-scale scenario. We retain the currently available spatial scale, able to represent a limited average region of the sea, and we introduce a new spatial macro-scale, able to represent the whole sea. At the macro-scale a single agent represents an area of five square nautical miles and manages groups of fish in different age classes. The interactions among the macro agents permit the exchange of individuals of each class among neighbor areas. A case study regarding the Solea solea (Linnaeus, 1758; Soleidae) stock of the northern Adriatic Sea is used to show the intended approach, taking into account the available data, coming from fishery independent scientific surveys. © Springer International Publishing Switzerland 2015.


Besio G.,University of Genoa | Mentaschi L.,University of Genoa | Mentaschi L.,National Institute of Nuclear Physics, Italy | Mazzino A.,University of Genoa | And 2 more authors.
Energy | Year: 2016

A state-of-the-art, in terms of spatio-temporal resolution (about 10 km and on a hourly basis) and temporal span (35 years), wave hindcast is exploited to update existing assessments of wave energy potential in the Mediterranean Sea. The hindcast, covering the period 1979-2013, has been obtained using WavewatchIII with calibrated source-term parameters recently proposed by L. Mentaschi et al. (2015) [1]. The main advantage of such a calibration is that it takes into account the peculiarity of the Mediterranean basin with respect to other calibrations carried out in the oceans. The high resolution allowed to perform a detailed analysis of wave energy potential characteristics providing information on seasonal and longer term variability necessary for reliable and optimal design of wave energy conversion devices. As a result, the identification of areas where the mean wave power reaches values of the order of 10 kW/m clearly emerge. However, these regions are not necessarily optimal in relation to the efficiency of energy extraction, due to possible relevant time variation of the energy availability. The high temporal resolution allows to address issues related to the time variability of the available resource and thus to provide a complete set of statistical information to carry out optimal design of WEC (wave energy converter). © 2015 Elsevier Ltd.


Mentaschi L.,University of Genoa | Mentaschi L.,National Institute of Nuclear Physics, Italy | Besio G.,University of Genoa | Cassola F.,University of Genoa | And 5 more authors.
Ocean Modelling | Year: 2013

In order to evaluate the reliability of numerical simulations in geophysical applications it is necessary to pay attention when using the root mean square error (RMSE) and two other indicators derived from it (the normalized root mean square error (NRMSE), and the scatter index (SI)). In the present work, in fact, we show on a general basis that, in conditions of constant correlation coefficient, the RMSE index and its variants tend to be systematically smaller (hence identifying better performances of numerical models) for simulations affected by negative bias. Through a geometrical decomposition of RMSE in its components related to the average error and the scatter error it can be shown that the above mentioned behavior is triggered by a quasi-linear dependency between these components in the neighborhood of null bias. This result suggests that smaller values of RMSE, NRMSE and SI do not always identify the best performances of numerical simulations, and that these indicators are not always reliable to assess the accuracy of numerical models. In the present contribution we employ the corrected indicator proposed by Hanna and Heinold (1985) to develop a reliability analysis of wave generation and propagation in the Mediterranean Sea by means of the numerical model WAVEWATCH III®, showing that the best values of the indicator are obtained for simulations unaffected by bias. Evidences suggest that this indicator provides a more reliable information about the accuracy of the results of numerical models. © 2013 Elsevier Ltd.


Deidda R.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | Deidda R.,University of Cagliari | Marrocu M.,Centro Of Ricerca | Caroletti G.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | And 10 more authors.
Hydrology and Earth System Sciences | Year: 2013

This paper discusses the relative performance of several climate models in providing reliable forcing for hydrological modeling in six representative catchments in the Mediterranean region. We consider 14 Regional Climate Models (RCMs), from the EU-FP6 ENSEMBLES project, run for the A1B emission scenario on a common 0.22° (about 24 km) rotated grid over Europe and the Mediterranean region. In the validation period (1951 to 2010) we consider daily precipitation and surface temperatures from the observed data fields (E-OBS) data set, available from the ENSEMBLES project and the data providers in the ECA&D project. Our primary objective is to rank the 14 RCMs for each catchment and select the four best-performing ones to use as common forcing for hydrological models in the six Mediterranean basins considered in the EU-FP7 CLIMB project. Using a common suite of four RCMs for all studied catchments reduces the (epistemic) uncertainty when evaluating trends and climate change impacts in the 21st century. We present and discuss the validation setting, as well as the obtained results and, in some detail, the difficulties we experienced when processing the data. In doing so we also provide useful information and advice for researchers not directly involved in climate modeling, but interested in the use of climate model outputs for hydrological modeling and, more generally, climate change impact studies in the Mediterranean region. © Author(s) 2013.


Delitala A.M.S.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | Gallino S.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | Villa L.,Consorzio Interuniversitario Nazionale per la Fisica delle Atmosfere e delle Idrosfere | Lagouvardos K.,Institute for Environmental Research | Drago A.,University of Malta
Theoretical and Applied Climatology | Year: 2010

The selection of ship routes based on modern weather forecasting is a mean of computing optimum shipping routes thereby increasing safety and comfort at sea, cutting down on transit time, and reducing fuel consumption. Further empirical research in the effectiveness of modern weather routing applications is required especially in applications concerning shorter routes in enclosed seas of limited geographical extent such as the Mediterranean Sea. The present study used two climatological simulations to test this state-of-the-art approach to ship routing. Simulations represented two theoretical routes: (1) a route between Italy and Greece and (2) a route between Cyprus and Italy. Both routes were analyzed across varying simulated climatic conditions and the results were compared with those of control routes. Furthermore, results were analyzed in terms of passenger and crew comfort, bunker consumption by ships, and time of crossing. The first simulation showed that weather routing would improve ship performance on 37% of days while the second simulation revealed that weather routing would support ship captains virtually all the time. © 2010 Springer-Verlag.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP-SICA | Phase: ENV.2009.1.1.5.2 | Award Amount: 4.16M | Year: 2010

With regard to the objectives specified in ENV-2009.1.1.5.2, modeling capabilities must be improved and appropriate tools developed to advance the capability to assess climate effects on water resources and uses. The project consortium will employ a combination of novel field monitoring concepts, remote sensing techniques, integrated hydrologic (and biophysical) modeling and socioeconomic factor analyses to reduce existing uncertainties in climate change impact analysis and to create an integrated quantitative risk and vulnerability assessment tool. Together, these will provide the necessary information to design appropriate adaptive water resources management instruments and select suitable agricultural practices under climate change conditions. The integrated risk and vulnerability analysis tool will also enable assessment of risks for conflict-inducing actions, e.g. migration. The improved models, new assessment tools, and their results will be evaluated against current methodologies. Improvements will be communicated to stakeholders and decision makers in a transparent, easy-to-understand form, enabling them to utilize the new findings in regional water resource and agricultural management initiatives as well as in the design of mechanisms to reduce potential for conflict (linkage to SSH-2009.4.2.1).


Cotroneo Y.,Parthenope University of Naples | Aulicino G.,Parthenope University of Naples | Ruiz S.,CSIC - Mediterranean Institute for Advanced Studies | Pascual A.,CSIC - Mediterranean Institute for Advanced Studies | And 5 more authors.
Journal of Marine Systems | Year: 2015

Despite an extensive bibliography for the circulation of the Mediterranean Sea and its sub-basins, the debate on mesoscale dynamics and their impacts on bio-chemical processes is still open because of their intrinsic time scales and of the difficulties in their sampling. In order to clarify some of these processes, the "Algerian BAsin Circulation Unmanned Survey-ABACUS" project was proposed and realized through access to the JERICO Trans National Access (TNA) infrastructure between September and December 2014. In this framework, a deep glider cruise was carried out in the area between the Balearic Islands and the Algerian coast to establish a repeat line for monitoring of the basin circulation. During the mission a mesoscale eddy, identified on satellite altimetry maps, was sampled at high-spatial horizontal resolution (4. km) along its main axes and from the surface to 1000. m depth. Data were collected by a Slocum glider equipped with a pumped CTD and biochemical sensors that collected about 100 complete casts inside the eddy. In order to describe the structure of the eddy, in situ data were merged with next generation remotely sensed data: daily synoptic sea surface temperature (SST) and chlorophyll concentration (Chl-a) images from the MODIS satellites, as well as sea surface height and geostrophic velocities from AVISO. From its origin along the Algerian coast in the eastern part of the basin, the eddy propagated northwest at a mean speed of about 4. km/day, with a mean diameter of 112-130. km, mean amplitude of 15.7. cm; the eddy was clearly distinguished from the surrounding waters thanks to its higher SST and Chl-a values. Temperature and salinity values over the water column confirm the origin of the eddy from the Algerian Current (AC) showing the presence of recent Atlantic water in the surface layer and Levantine Intermediate Water (LIW) in the deeper layer. The eddy footprint is clearly evident in the multiparametric vertical sections conducted along its main axis.Deepening of temperature, salinity and density isolines at the center of the eddy is associated with variations in Chl-a, oxygen concentration and turbidity patterns. In particular, at 50. m depth along the eddy borders, Chl-a values are higher (1.1-5.2. μg/l) in comparison with the eddy center (0.5-0.7. μg/l) with maximum values found in the southeastern sector of the eddy.Calculation of geostrophic velocities along transects and vertical quasi-geostrophic velocities (QG-w) over a regular 5. km grid from the glider data helped to describe the mechanisms and functioning of the eddy. QG-w presents an asymmetric pattern, with relatively strong downwelling in the western part of the eddy and upwelling in the southeastern part. This asymmetry in the vertical velocity pattern, which brings LIW into the euphotic layer as well as advection from the northeastern sector of the eddy, may explain the observed increases in Chl-a values. © 2015 Elsevier B.V.

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