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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.

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.

La Jeunesse I.,University of Tours | La Jeunesse I.,University of Angers | Cirelli C.,University of Tours | Sellami H.,Catholic University of Louvain | And 4 more authors.
Ocean and Coastal Management | Year: 2015

The present paper provides a reflection on threats to integrated management of the Thau coastal lagoon due to climate change and the multi-scalar water scarcity adaptation strategy. This study proposes first to depict the Thau water governance assessed through a water use and social network analysis and its capacity to manage water quality. Next, this paper provides a downscaled study on the climate change impacts on the hydrological budget of the entire Thau catchment in 2041-2070 compared with the 1971-2000 reference period, a methodology developed during the CLIMB EU research program. Following local climate change impacts, the importation of a new water resource to secure water uses is presented in regards to the capacity of local water governance to maintain coherence between integrated land planning and integrated water management planning based on water quality issues of the Thau coastal lagoon. The study underlines that although the water uses are currently secured thanks to the regional transfer of water, they are not coherent with local water management and create new vulnerabilities in the context of climate change. Moreover, the regional decision to end financial support for the more efficient, existing network for the water quality survey of regional coastal lagoons breaks up the local water governance. This paper demonstrates why keeping this network would have been absolutely necessary for encouraging a governance capable of proposing sustainable solutions to water quality challenges induced by climate change. © 2015 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.

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.

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