Maria Vittoria Struglia

The Hydrological Cycle in the Mediterranean Region and Implications for the Water Budget of the Mediterranean Sea

Abstract The hydrological cycle in the Mediterranean region is analyzed focusing on climatology and interannual to interdecadal variability, in particular long-term changes related to the well-established North Atlantic Oscillation (NAO) teleconnection. Recent atmospheric reanalyses and observational datasets are used: precipitation, evaporation, and moisture flux from 50 yr of NCEPs and 15 yr of ECMWFs reanalyses; precipitation from the Climate Prediction Center Merged Analysis of Precipitation (CMAP) and the East Anglia University Climate Research Unit (CRU) datasets; and evaporation from the University of Wisconsin—Milwaukee (UWM) Comprehensive Ocean–Atmosphere Data Set (COADS). A budget analysis is performed to study contributions to the freshwater flux into the Mediterranean Sea, including atmospheric as well as river discharge inputs. The total river discharge is derived using historical time series from Mediterranean Hydrological Cycle Observing System (MED-HYCOS) and Global Runoff Data Center (G...

Med-CORDEX initiative for Mediterranean climate studies

The Mediterranean is expected to be one of the most prominent and vulnerable climate change “hot spots” of the 21st century, and the physical mechanisms underlying this finding are still not clear. Furthermore complex interactions and feedbacks involving ocean-atmosphere-land-biogeochemical processes play a prominent role in modulating the climate and environment of the Mediterranean region on a range of spatial and temporal scales. Therefore it is critical to provide robust climate change information for use in Vulnerability/Impact/Adaptation assessment studies considering the Mediterranean as a fully coupled environmental system. The Med-CORDEX initiative aims at coordinating the Mediterranean climate modeling community towards the development of fully coupled regional climate simulations, improving all relevant components of the system, from atmosphere and ocean dynamics to land surface, hydrology and biogeochemical processes. The primary goals of Med-CORDEX are to improve understanding of past climate variability and trends, and to provide more accurate and reliable future projections, assessing in a quantitative and robust way the added value of using high resolution and coupled regional climate models. The coordination activities and the scientific outcomes of Med-CORDEX can produce an important framework to foster the development of regional earth system models in several key regions worldwide.

River Discharge into the Mediterranean Sea: Climatology and Aspects of the Observed Variability

Abstract River discharge across the Mediterranean catchment basin is investigated by means of an extensive dataset of historical monthly time series to represent at-best discharge into the sea. Results give an annual mean river discharge into the Mediterranean of 8.1 × 103 m3 s−1, or at most a value that should not exceed 10.4 × 103 m3 s−1. The seasonal cycle has an amplitude of 5 × 103 m3 s−1, with a dry season in midsummer and a peak flow in early spring. Dominant contributions are from Europe with a climatological annual mean of 5.7 × 103 m3 s−1. Discharge in the Adriatic Sea, the Gulf of Lion, and the Aegean Sea together account for 62% of Mediterranean discharge, which mostly occurs in the Adriatic (2.7 × 103 m3 s−1). The North Atlantic Oscillation (NAO) impacts Mediterranean discharge primarily in winter, with most river discharges across the Mediterranean catchment being anticorrelated with the NAO. Related winter anomalies are about 10%–20% of the winter means. During the period 1960–90, Mediterra...

Future Climate Projections

In this chapter we show results from an innovative multi-model system used to produce climate simulations with a realistic representation of the Mediterranean Sea. The models (hereafter simply referred to as the “CIRCE models”) are a set of five coupled climate models composed by a high-resolution Mediterranean Sea coupled with a relatively high-resolution atmospheric component and a global ocean, which allow, for the first time, to explore and assess the role of the Mediterranean Sea and its complex, small-scale dynamics in the climate of the region. In particular, they make it possible to investigate the influence that local air-sea feedbacks might exert on the mechanisms responsible for climate variability and change in the European continent, Middle East and Northern Africa. In many regards, they represent a new and innovative approach to the problem of regionalization of climate projections in the Mediterranean region.

Impacts of Climate Change on Freshwater Bodies: Quantitative Aspects

In this chapter we present the results of the impact assessment on freshwater bodies in the Mediterranean region. Starting from the characterization of the general features of Mediterranean hydrology, main focus is given on large river basins discharging into the Mediterranean sea as well as to small and medium scale catchments representing almost half of the entire discharging basin. Groundwater representing a fundamental water resource for Mediterranean countries was also considered. Climate change impacts on the hydrological behavior of large river basins is investigated through the IRIS computational tool which was proved to be a versatile instrument for both climate studies and the assessment of model ability to simulate the hydrological cycle at catchment scale, taking advantage of the available observed discharge series to evaluate the reliability of future discharge projections. The results regarding some representative Mediterranean rivers using multiple climate models developed inside Circe have highlighted an open spread among twenty-first century projections. The problem of the effective information content of climate model simulations with respect to small scale impact studies is developed at the scale of medium and small catchments. Particularly at the space-time scales needed to describe the terrestrial water cycle in Mediterranean environments this is recognized among the most difficult problems facing both science and society. Therefore downscaling and bias-correction requirements have been treated in this chapter through specific methodologies which integrate dynamical downscaling with statistical downscaling always adopting ground based observation of climate variables as a powerful means to obtain more robust climate forcing for hydrological models. The assessment of climate change impacts on small and medium size catchments is developed through some representative case studies in which downscaling methodologies have been applied thanks to the availability of dense climate measurement networks. The impact assessment of water resources in the Apulia region (southern Italy) revealed a marked increase in the variability of hydrologic regimes as consequence of the increased rainfall variability predicted for the twenty-first century. Conversely only slight decreasing trends were detected in the annual water balance components. Similar results were found on a carbonate aquifer in Southern Italy in which a large Apennine spring have been selected as a significant hydrogeological systems with minimal anthropogenic pressures in the recharge areas. Finally a specific session is dedicated to the role of artificial dams in reducing the possible impacts of climate change. In particular, methodologies for the assessment of optimal dam dimensioning under climate change are presented as well as a reliability assessment based on water supply and demand imbalances.

Impacts of Climate Change on Water Quality

In this chapter we present the result of two model exercises aiming at simulating the impact of climate change onto two classes of surface aquifers: lakes and rivers. Section 10.1 focuses on the impact of global warming on the thermal structure of two Italian South alpine lakes: Lake Como and Pusiano. Long term hydrodynamic simulations (1953–2050) were performed using the hydrodynamic model DYRESM (Dynamic Reservoir Simulation Model). DYRESM simulations were forced with downscaled regional climate scenarios undertaken within CIRCE. Our model simulations projected a yearly average temperature increase of 0.04°C year−1 for the period 1970–2000 and 0.03°C year−1 for the period 2001–2050 (A1b IPCC scenario). These results are in line with those detected in long term research studies carried out world-wide. This temperature increase is first responsible for a general increase of the water column stability and for a reduction of the mass transfer between deep and surface waters with direct implications on the oxygen and nutrient cycles. The magnitude of the temperature increase is also sufficient to impact on the growth of phytoplankton populations and it is likely one of the concurrent causes promoting the massive cyanobacteria blooms, recently detected in the two Italian case studies and in different lake environments in Europe. Section 10.2 approaches the problem of establishing a methodology to estimate the average yearly nutrient (phosphorus and nitrogen) river loads under present climate conditions and under the forcing of climate change. The case study is the Po River the largest hydrological basin in Italy and the third tributary of the Mediterranean semi-enclosed basin. The methodology developed in this study is based on a hierarchy of different numerical models which allowed to feed the MONERIS model (MOdeling Nutrient Emissions into River System) with the necessary meteorological and hydrological forcing. MONERIS was previously calibrated (1990–1995) and validated (1996–2000) under past conditions and then run under current conditions to define a control experiment (CE). Current nutrient loads have been estimated in 170,000 and 8,000 t year−1 respectively for nitrogen and phosphorus. Approximately 70% of the nitrogen load is from diffuse sources while 65% of the phosphorus load originates from point sources. Nutrient loads projections at 2100 (under different IPCC scenarios) allowed to estimate that both nitrogen and phosphorus loads are strictly dependent on the resident population which is responsible of a 61 and 41% increase respectively for nitrogen and phosphorus. Projected nutrient load variations were found to be negligible when holding the resident population constant. Finally the phosphorus load is markedly influenced by the efficiency of the waste water treatment plants (WWTPs).

Risk Analysis and Crisis Scenario Evaluation in Critical Infrastructures Protection

Critical Infrastructures (CI) are technological systems (encompassing telecommunication and electrical networks, gas and water pipelines, roads and railways) at the heart of citizen’s life. CI protection, issued to guarantee their physical integrity and the continuity of the services they deliver (at the highest possible Quality of Service), is one of the major concern of public authorities and of private operators, whose economic results strictly depend on the way they are able to accomplish this task . Critical Infrastructure Protection (CIP) is thus a major issue of nations as the impact of CIs malfunctioning or, even, their outage might have dramatic and costly consequences for humans and human activities (1; 2). EU has recently issued a directive to member states in order to increase the level of protection to their CIs which, in a EU-wide scale, should be considered as unique, trans-national bodies, as they do not end at national borders but constitute an unique, large system covering all the EU area (3). Activities on CI protection attempt to encompass all possible causes of faults in complex networks: from those produced by deliberate human attacks to those occurring in normal operation conditions up to those resulting from dramatic events of geological or meteorologic origin. Although much effort has been devoted in realizing new strategies to reduce the risks of occurrence of events leading to the fault of CI elements, a further technological activity is related to the study of possible strategies to be used for predicting and mitigating the effects produced by CI crisis scenarios. To this aim, it is evident that a detailed knowledge of what is going to happen might enormously help in preparing healing or mitigation strategies in due time, thus reducing the overall impact of crises, both in social and economic terms. CIP issues are difficult to be analyzed as one must consider the presence of interdependence effects among different CIs. A service reduction (or a complete outage) on the electrical system, for instance, has strong repercussions on other infrastructures which are (more or less) tightly related to the electrical system. In an electrical outage case, for instance, also vehicular traffic might have consequences as petrol pumps need electrical power to deliver petrol; pay tolls do need electrical current to establish credit card transactions. As such, also Risk Analysis and Crisis Scenario Evaluation in Critical Infrastructures Protection

Marine Energy Exploitation in the Mediterranean Region: Steps Forward and Challenges

Technologies for the conversion of Marine Energy (ME) into electricity are now ready for full-scale deployment in farms of devices, making the final step from demonstration to operability and commercial exploitation. Although marine energy is more abundant along the Atlantic and Nordic European coasts, significant resources are also available in the Mediterranean Sea, opening up new perspectives for sustainable energy production in sensitive coastal areas and for the economic development of Southern Europe. The implementation of ME converters in the Mediterranean is also liable to induce significant technological advancements, as the low energy levels impose more restrictive constraints on device efficiency and environmental compatibility, while the milder climate allows the testing of concepts and prototypes in the natural environment at more affordable costs. Research institutions and industrial players in Mediterranean countries have in fact already taken up the challenge. The energy sector now adds up to the many different traditional maritime activities and to the new ocean-related industries that are developing, potentially exacerbating the competition for the use of marine space in the Mediterranean region. As the prospective sea use patterns are rapidly changing, an adequate international legal and policy framework needs to be designed for the coherent management of sea space, and Marine Spatial Planning needs to be finally implemented. To this end, the creation of transnational clusters of stakeholders is expected to be an effective catalyzer.