http://hdl.handle.net/2122/164 Sat, 25 May 2013 13:29:55 GMT 2013-05-25T13:29:55Z http://hdl.handle.net/2122/8650 Title: Different types of sediment gravity flows detected in the Var submarine canyon (northwestern Mediterranean Sea) Authors: Khripounoff, A.; Ifremer; Crassous, P.; Ifremer; Lo Bue, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Dennielou, B.; Ifremer; Silva Jacinto, R.; Ifremer Abstract: Current velocities and vertical sediment fluxes in the Var submarine canyon were assessed at three stations respectively at 800 m, 1200 m and 1800 m depth, using moorings deployed for 4 months during winter 2008–2009. During this period, we observed three major sediment gravity flows, all characterized by sudden increases in current velocity that lasted 2–5 h and by downward particle fluxes. Each gravity flow, described using a high frequency current meter and two Acoustic Doppler Current Profiler (75 and 300 kHz ADCP) showed distinctive features. The first event, triggered during a flood of the Var River, was determined to be a hyperpycnal current with a large vertical extent (>100 m high) and relatively low velocity (40 cm s 1). The second event, observed after a Var River flood, was more energetic with a maximum horizontal current peak of 60 cm s 1 but with a low vertical extent (30 m high). This event was considered to be a turbidity landslide. The third was the result of a local canyon wall failure. It was characterized by a speed of >85 cm s 1. These peaks of current speed were associated with large clouds of material that transported sediment along the canyon and reached up to 200 g m 2 d 1 of sediment (>1 g m 2 d 1 of organic carbon). Our measurements in the Var canyon show the important role of gravity flows transporting particulate matter to the deep-sea floor. These large inputs of sediment and organic carbon may have a significant impact on deep-sea carbon storage in the Mediterranean Sea. Tue, 18 Sep 2012 22:00:00 GMT http://hdl.handle.net/2122/8650 2012-09-18T22:00:00Z http://hdl.handle.net/2122/8581 Title: Strengthening of the hydrological cycle in future scenarios: atmospheric energy and water balance perspective Authors: Alessandri, A.; ENEA; Fogli, P. G.; CMCC; Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Zeng, N.; University of Mariland Abstract: Future climate scenarios experiencing global warming are expected to strengthen the hydrological cycle during the 21st century (21C). We analyze the strengthening of the global-scale increase in precipitation from the perspective of changes in whole atmospheric water and energy balances. By combining energy and water equations for the whole atmosphere, we obtain constraints for the changes in surface fluxes and partitioning at the surface between sensible and latent components. We investigate the differences in the strengthening of the hydrological cycle in two centennial simulations performed with an Earth system model forced with specified atmospheric concentration pathways. Alongside the Special Report on Emissions Scenario (SRES) A1B, which is a medium-high non-mitigation scenario, we consider a new aggressive-mitigation scenario (E1) with reduced fossil fuel use for energy production aimed at stabilizing global warming below 2 K. Our results show that the mitigation scenario effectively constrains the global warming with a stabilization below 2 K with respect to the 1950–2000 historical period. On the other hand, the E1 precipitation does not follow the temperature field toward a stabilization path but continues to increase over the mitigation period. Quite unexpectedly, the mitigation scenario is shown to strengthen the hydrological cycle even more than SRES A1B till around 2070. We show that this is mostly a consequence of the larger increase in the negative radiative imbalance of atmosphere in E1 compared to A1B. This appears to be primarily related to decreased sulfate aerosol concentration in E1, which considerably reduces atmospheric absorption of solar radiation compared to A1B. The last decades of the 21C show a marked increase in global precipitation in A1B compared to E1, despite the fact that the two scenarios display almost the same overall increase of radiative imbalance with respect to the 20th century. Our results show that radiative cooling is weakly effective in A1B throughout the 21C. Two distinct mechanisms characterize the diverse strengthening of the hydrological cycle in the middle and end- 21C. It is only through a very large perturbation of surface fluxes that A1B achieves a larger increase in global precipitation in the last decades of the 21C. Our energy/water budget analysis shows that this behavior is ultimately due to a bifurcation in the Bowen ratio change between the two scenarios. This work warns that mitigation policies that promote aerosol abatement, may lead to an unexpected stronger intensification of the hydrological cycle and associated changes that may last for decades after global warming is effectively mitigated. On the other hand, it is also suggested that predictable components of the radiative forcing by aerosols may have the potential to effectively contribute to the decadal-scale predictability of changes in the hydrological strength. Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/8581 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8386 Title: Tracking bottom waters in the Southern Adriatic Sea applying seismic oceanography techniques Authors: Carniel, S.; CNR-ISMAR; Bergamasco, A.; CNR-ISMAR; Book, J. W.; NRL; Hobbs, R. W.; Univ. of Durham; Sclavo, M.; CNR-ISMAR Abstract: We present the first results from the Seismic Oceanography (SO) cruise ADRIASEISMIC where we successfully imaged thermohaline fine structures in the shallow water environment (50-150 m) of the southern Adriatic Sea during March 2009 using a compact two GI-gun seismic source. The SO observations are complemented with traditional oceanographic and micro-structure measurements and show that SO can operate over almost the entire water column except (in our experimental layout) for the uppermost 50 m. After processing to enhance the signal-to-noise ratio, the seismic reflection data have a vertical resolution of ~10 m and a horizontal resolution of ~100 m and provide a laterally continuous map of significant thermohaline boundaries that cannot be achieved with conventional physical oceanography measurements alone. ADRIASEISMIC specifically targeted structures in shallow waters, namely along the western margin of the southern Adriatic Sea, between the Gargano peninsula and the Bari canyon, and imaged the Northern Adriatic Dense Water (NAdDW), a bounded cold and relatively dense water mass flowing from the northern Adriatic Sea. The seismic data acquired in Bari canyon and offshore of the Gargano promontory show many regions of strongly reflecting shallow structures, and the incorporation of XBTs measurements with these data demonstrate that they can be interpreted in terms of temperature structures and gradients. In the Gargano region several warm water intrusive structures are mapped along with the offshore transitional edge of cold waters of strong NAdDW influence. In Bari Canyon, waters with NAdDW influence are further mapped extending over the shelf and off the slope into a 5 km long tongue extending offshore between depths of 200-300 m. More generally, even though neither cascading nor open-ocean deep convection process appeared to be evident during March 2009, the SO approach was able to map details of thermal features not resolved by even closely spaced XBT measurements. Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/8386 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8189 Title: Towards validating a last generation, integrated wave-current-sediment numerical model in coastal regions using video measurements Authors: Carniel, S.; CNR-ISMAR; Sclavo, M.; CNR-ISMAR; Archetti, R.; Univ. of Bologna Abstract: his paper presents the first steps in the implementation of a morphological numerical model to be applied in the Bevano River region, a shallow water area in the Adriatic Sea, with the aim of helping the identification and assessment of erosional patterns and bottom morphological modifications induced by severe marine storms. The numerical modeling, performed using a fully 3D coupled wave-current-sediment version of the ROMS model, has been complemented with in situ data analysis and observations: a first ... Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/8189 2010-12-31T23:00:00Z http://hdl.handle.net/2122/8035 Title: Stress-induced temperature variations in groundwater of the Monferrato area (north-western Italy) Authors: De Gregorio, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Federico, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Cappuzzo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Giudice, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Gurrieri, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Boschi, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia Abstract: Although characterized by low seismicity, the Monferrato area of north-western Italy was affected by earthquakes, of magnitude M5.1 and M4.8, in 2000 and 2001. At the same time, marked changes were recorded in water temperature and chemistry in several wells within the epicentral area. In May 2004, an automatic network for the continuous monitoring of groundwater was installed in selected wells to study the phenomenon. Here, we report on data collected during a 3-year period of groundwater monitoring. During the first year, episodes of water heating (by up to 20°C) were observed in one monitored well. The temporal analysis of the seismic activity recorded in the area revealed as almost all seismic events occurred during the period of elevated water temperatures. The similar timing of earthquakes and groundwater-temperature anomalies suggests that both may be triggered by the same processes acting in the crust. Mon, 30 Apr 2012 22:00:00 GMT http://hdl.handle.net/2122/8035 2012-04-30T22:00:00Z http://hdl.handle.net/2122/7312 Title: The driving forces of the biotic processes along an offshore gradient in the Ligurian basin (Portofino Promontory) during 2008 Authors: Locritani, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Gasparini, G. P.; Consiglio Nazionale delle Ricerche ISMAR, La Spezia, Italy; Carmisciano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Castellano, M.; Universita’ degli studi di Genova, Genova, Italy; Povero, P.; Universita’ degli studi di Genova, Genova, Italy Abstract: The marine coastal area of the Portofino Promontory, located in the North-East side of the Ligurian basin (Mediterranean Sea), has been studied since 1980’s to identify its main ecological characteristics. The large physical, chemical and biological dataset available for this site (LTER sites) represents a powerful tool for the reliable reconstruction of seasonal cycles and allow the differentiation of regular and recurrent patterns from occasional and exceptional events. This long-term monitoring reveled an increases in the average monthly temperature along the water column in the last 10 years compare with the previous decade (1985-1995), with a high inter-annual variability and some specific episodic occurrence of thermal anomalies. The physical features of the water column seems to have a strict relation with the phytoplankton biomass fluctuations. A detailed study of 2008 intended to analyze a wider area, in order to compare the driving forces influencing the development of biotic process along an offshore gradient. Sat, 02 Apr 2011 22:00:00 GMT http://hdl.handle.net/2122/7312 2011-04-02T22:00:00Z http://hdl.handle.net/2122/7060 Title: Geochemical monitoring of volcanic lakes. A generalized box model for active crater lakes Authors: Rouwet, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Tassi, F.; Università degli Studi di Firenze, Dipartimento di Scienze della Terra, Firenze, Italy Abstract: In the past, variations in the chemical contents (SO4 2−, Cl−, cations) of crater lake water have not systematically demonstrated any relationships with eruptive activity. Intensive parameters (i.e., concentrations, temperature, pH, salinity) should be converted into extensive parameters (i.e., fluxes, changes with time of mass and solutes), taking into account all the internal and external chemical–physical factors that affect the crater lake system. This study presents a generalized box model approach that can be useful for geochemical monitoring of active crater lakes, as highly dynamic natural systems. The mass budget of a lake is based on observations of physical variations over a certain period of time: lake volume (level, surface area), lake water temperature, meteorological precipitation, air humidity, wind velocity, input of spring water, and overflow of the lake. This first approach leads to quantification of the input and output fluxes that contribute to the actual crater lake volume. Estimating the input flux of the "volcanic" fluid (Qf - kg/s) –– an unmeasurable subsurface parameter –– and tracing its variations with time is the major focus during crater lake monitoring. Through expanding the mass budget into an isotope and chemical budget of the lake, the box model helps to qualitatively characterize the fluids involved. The (calculated) Cl− content and dD ratio of the rising "volcanic" fluid defines its origin. With reference to continuous monitoring of crater lakes, the present study provides tips that allow better calculation of Qf in the future. At present, this study offers the most comprehensive and up-to-date literature review on active crater lakes. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/7060 2010-12-31T23:00:00Z http://hdl.handle.net/2122/6999 Title: Carbonate coastal aquifer of Vlora bay and groundwater submarine discharge (southwestern Albania) Authors: Polemio, M.; CNR-IRPI; Pambuku, A.; Albanian Geological Service; Limoni, P.P.; CNR-IRPI; Petrucci, O.; CNR IRPI Abstract: The study discusses the large karstic coastal aquifer of Vlora Bay. This case is peculiar, as the submarine groundwater discharge has a relevant rate of terrestrial inflow in an almost closed bay that is located in an environmentally valuable area. The study is based on four methodological activities: geological and hydrogeological conceptualisation, climatic study and hydrological balance, numerical modelling, and monitoring. A geodatabase was created considering hundreds of data points (wells, springs, rivers, lagoons, and seas) and monthly time series of rainfall, temperature, and river discharge. Monitoring activity was realised over a hydrological year, installing a rainfall network tool and using a network of tens of sampling points, including springs, wells, lagoons and sea. Chemical-physical and stable isotope determinations were realised. Two main groups of aerial springs are fed by the aquifer, one of which is of a coastal type. The total spring discharge is roughly 4 m3/s. The GSD was assessed as being equal to 1.4 m3/s on the basis of the current rate of anthropic discharge and climatic conditions. The study showed the peculiarities of this carbonate coastal aquifer and the importance of its groundwater, which is the chief water source for the third-largest Albanian town. The groundwater quality was generally high, mainly due to the negligible presence of contamination sources on the relief in which the aquifer outcrops. The rate of seawater intrusion effects was also low, thanks to favourable aquifer 3-D geometry and high recharge levels. The increasing anthropic activities constitute a relevant risk in the absence of the introduction of rigorous land and water management criteria. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/6999 2010-12-31T23:00:00Z http://hdl.handle.net/2122/6990 Title: CARATTERI IDROGEOLOGICI DELLE SORGENTI CIRCOSTANTI IL LAGO DI LESINA (GARGANO) Authors: DI CAGNO, M.; CNR-IRPI; DRAGONE, V.; CNR-IRPI; POLEMIO, M.; CNR-IRPI; VIRGA, R.; CNR IRPI Abstract: Si studia il contributo alla Laguna di Lesina proveniente da tre principali sorgenti alimentate dal vasto acquifero carsico del Gargano. Con un approccio idrologico-statistico si determina l'estensione dell'area di alimentazione delle sorgenti. Tue, 30 Nov 1999 23:00:00 GMT http://hdl.handle.net/2122/6990 1999-11-30T23:00:00Z http://hdl.handle.net/2122/6595 Title: Groundwaters of Mt. Vulture volcano, southern Italy: Chemistry and sulfur isotope composition of dissolved sulfate Authors: Paternoster, M.; Dipartimento di Chimica, Universitá degli Studi della Basilicata, Campus Macchia Romana, I-85100 Potenza, Italy; Parisi, S.; Dipartimento di Scienze Geologiche, Universitá degli Studi della Basilicata, Campus Macchia Romana, I-85100 Potenza, Italy; Caracausi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Mongelli, G.; Dipartimento di Chimica, Universitá degli Studi della Basilicata, Campus Macchia Romana, I-85100 Potenza, Italy Abstract: We report the chemical composition of groundwaters—including the first data on the sulfur isotopic composition of dissolved sulfate—from the volcanic aquifers of Mt. Vulture, one of the most important hydrological basins of southern Italy. A total of 27 water samples taken at different altitudes among drilled wells and springs were collected. The majority of groundwaters have a bicarbonate alkaline and bicarbonate alkaline-earth composition. High-salinity waters are sulfatebicarbonate alkaline in composition. The water-rock interaction process is mainly affected from uprising of CO2-rich gases which cause an increase of the water acidity promoting basalt weathering with an enrichment in certain chemical species (i.e., Na+, Ca2+, SO4 2–) and a high total carbon content. The δ34S values of dissolved sulfate ranging from +4‰ to +8.6‰ can be explained by leaching of volcanites. Higher δ34S values (from 9.6‰ to 10.4‰) detected in a few water springs can be ascribed either to the interaction with the pyroclastic layer rich in feldspathoids, such as haüyna, that have sulfur isotopic compositions up to +10.6‰ or animal manure contamination inducing localized bacterial sulfate reduction with an increase in the δ34S of sulfate. Taking into account that Upper Triassic evaporite deposits have higher δ34S values (from +13.5‰ to +17.4‰,) than those measured in all water samples the dissolution of these deposits could be excluded. Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2122/6595 2009-12-31T23:00:00Z