http://hdl.handle.net/2122/156 2013-05-20T22:37:55Z http://hdl.handle.net/2122/8587 Title: Ensemble spread-based assessment of observation impact: Application to a global ocean analysis system Authors: Storto, A.; CMCC; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Dobricic, S.; CMCC Abstract: This article explores an ensemble strategy for evaluating the impact of different observing networks. The impact is represented by the relative ensemble spread increase, in model space, of data-denial ensemble simulations with respect to an ‘all-observation’ ensemble experiment, evaluated independently for each observing network. The forecast-error covariance intercomparison reduces to the ensemble spread intercomparison; thus, the method can be applied to any assimilation system and requires only the proper construction of an ensemble system, although the impact assessment results depend on the specific configuration of the investigated analysis system. Our approach allows us to determine the impact of the observing networks in model space (unlike Observing System Experiments) and for different forecast ranges of the ocean general circulation model. No tangent-linear and adjoint coding of the ocean model are required. The method is applied for demonstration to a large-scale global ocean variational analysis system. The ensemble members are generated by (i) perturbing the observations within the 3D-Var assimilation scheme, (ii) perturbing the surface forcing, and (iii) stochastically perturbing the ocean model parametrisation tendencies. The impact is calculated for CTDs, XBTs, moorings, Argo, sea-level anomaly observations and sea-surface temperature measurements from space-borne microwave instruments within the three-year period from January 2003 to December 2005. It turns out, on the global scale, that altimetry exhibits the largest impact on near-surface temperature and sea-surface height. In contrast, deep-ocean impacts are led by the Argo float network. As expected, space-borne observations (sea-level anomaly and sea-surface temperature observations) increase their impact in the Southern Ocean, due to the lack of a robust network of in situ observations. The results of the impact on the salinity indicate the great importance of Argo floats, especially in the northern Extratropics. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8501 Title: Mazara del Vallo tide gauge observations (1906-1916): land subsidence or sea level rise? Authors: Olivieri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Spada, G.; Dipartimento di Scienze di Base e Fondamenti, Urbino University “Carlo Bo”; Antonioli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Galassi, G.; Dipartimento di Scienze di Base e Fondamenti, Urbino University “Carlo Bo” Abstract: Tide gauge data constitute an invaluable tool for the interpretation of short and long-term sea level changes occurring in the Mediterranean Sea. The complex geophysical environment and the limited amount of sufficiently long records make the interpretation of local signals problematic, since these are often affected by interlacing processes. Starting from newly disclosed tide gauge records from the site of Mazara del Vallo (SW Sicily), we analyze simultaneously the time series available from other locations in Sicily across the beginning of the 20th century (Messina and Palermo). Despite the limited record length, we show that these observations provide new perspectives on the causes of the observed sea level variations in the central Mediterranean region, and in particular they challenge previous tenets regarding the extent of land movements caused by the 1908 Messina Straits earthquake. 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8459 Title: NEMO-SN1 (Western Ionian Sea, off Eastern Sicily): Example of architecture of a cabled observatory Authors: Favali, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Azzarone, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Badiali, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Beranzoli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Qamili, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; De Caro, M.G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Doumaz, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Embriaco, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Falcone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Giovanetti, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Lo Bue, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Marinaro, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Monna, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Montuori, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Sgroi, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Vinci, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; NEMO Collaboration, NEMO Collaboration; INFN - Istituto Nazionale di Fisica Nucleare (INFN), Italy; Chierici, F.; CNR-ISMAR - Consiglio Nazionale delle Ricerche, Istituto delle Scienze Marine; Pignagnoli, L.; CNR-ISMAR - Consiglio Nazionale delle Ricerche, Istituto delle Scienze Marine; Zitellini, N.; CNR-ISMAR - Consiglio Nazionale delle Ricerche, Istituto delle Scienze Marine; Bruni, F.; Tecnomare S.p.A, Italy; Gasparoni, F.; Tecnomare S.p.A, Italy Abstract: NEMO-SN1, located in the central Mediterranean Sea, Western Ionian Sea, off Eastern Sicily Island (Southern Italy) at 2100 m water depth, 25 km from the harbour of the city of Catania, is a prototype of a cabled deep-sea multiparameter observatory and the first operating with real-time data transmission in Europe since 2005. NEMO-SN1 is also the first-established node of EMSO (European Multidisciplinary Seafloor Observatory, http://emso-eu.org), one of the incoming European large-scale research infrastructure included since 2006 in the Roadmap of the ESFRI (European Strategy Forum on Research Infrastructures, http://cordis.europa.eu/esfri/roadmap.htm), which will specifically address long-term monitoring of environmental processes related to Marine Ecosystems, Climate Change and Geo-hazards. NEMO-SN1 has been deployed and developed over the last decade thanks to Italian resources and to the EC project ESONET-NoE (European Seas Observatory NETwork - Network of Excellence, 2007-2011) that funded the LIDO-DM (Listening to the Deep Ocean - Demonstration Mission) and a technological interoperability test (http://www.esonet-emso.org/esonet-noe/). NEMO-SN1 is performing geophysical and environmental long-term monitoring by acquiring seismological, geomagnetic, gravimetric, accelerometric, physico-oceanographic, hydro-acoustic, bioacoustic measurements specifically related to earthquakes and tsunamis generation and ambient noise characterisation in term of marine mammal sounds, environmental and anthropogenic sources. A further main feature of NEMO-SN1 is to be an important test-site for the construction of KM3NeT (Kilometre-Cube Underwater Neutrino Telescope, http://www.km3net.org/), another large-scale research infrastructure included in the ESFRI Roadmap constituted by a large volume neutrino telescope. The description of the observatory and the most recent data acquired will be presented and framed in the general objectives of EMSO. 2011-04-04T22:00:00Z http://hdl.handle.net/2122/8334 Title: NEMO-SN1 Abyssal Cabled Observatory in the Western Ionian Sea Authors: Favali, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Chierici, F.; Istituto di Radio Astronomia-INAF; Marinaro, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Giovanetti, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Azzarone, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Beranzoli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Embriaco, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Monna, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Lo Bue, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Sgroi, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Badiali, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Qamili, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; De Caro, M. G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Falcone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Montuori, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Frugoni, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; NEMO Collaboration; INFN - Istituto Nazionale di Fisica Nucleare; Pignagnoli, L.; CNR-ISMAR - Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, Italy; Zitellini, N.; CNR-ISMAR - Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, Italy; Federico, B.; Bruni, F.; Tecnomare S.p.A, Italy; Gasparoni, F.; Tecnomare S.p.A, Italy; Pavan, G.; CIBRA, Università di Pavia, Italy Abstract: The “NEutrino Mediterranean Observatory - Submarine Network 1” (NEMO-SN1) seafloor observatory is located in the central Mediterranean Sea, Western Ionian Sea, off Eastern Sicily (Southern Italy) at 2100 m water depth, 25 km from the harbour of the city of Catania. It is a prototype of a cabled deep-sea multiparameter observatory and the first one operating with real-time data transmission in Europe since 2005. NEMO-SN1 is also the first-established node of the “European Multidisciplinary Seafloor and water column Observatory” (EMSO, http://www.emso-eu.org), one of the incoming European large-scale research infrastructures included in the Roadmap of the “European Strategy Forum on Research Infrastructures” (ESFRI, http://cordis.europa.eu/esfri/roadmap.htm) since 2006. EMSO will specifically address long-term monitoring of environmental processes related to Marine Ecosystems, Climate Change and Geo-hazards. NEMO-SN1 has been deployed and developed over the last decade thanks to Italian funding and to the EC project “European Seas Observatory NETwork - Network of Excellence” (ESONET-NoE, 2007-2011) that funded the “Listening to the Deep Ocean - Demonstration Mission” (LIDO-DM) and a technological interoperability test (http://www.esonet-emso.org/). NEMOSN1 is performing geophysical and environmental long-term monitoring by acquiring seismological, geomagnetic, gravimetric, accelerometric, physico-oceanographic, hydroacoustic, bio-acoustic measurements. Scientific objectives include studying seismic signals, tsunami generation and warnings, its hydroacoustic precursors, and ambient noise characterisation in terms of marine mammal sounds, environmental and anthropogenic sources. NEMO-SN1 is also an important test-site for the construction of the “Kilometre-Cube Underwater Neutrino Telescope” (KM3NeT, http://www.km3net.org/), another large-scale research infrastructure included in the ESFRI Roadmap based on a large volume neutrino telescope. The description of the observatory and its most recent implementations is presented. On 9th June, 2012 NEMO-SN1 was successfully deployed and is working in real-time. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8067 Title: Towards assessing the Adriatic Sea coastal vulnerability to regional climate change scenarios: preliminary results Authors: Carniel, Sandro Abstract: Preliminary results from numerical climate simulations of the Adriatic sea at high resolution (1/25°), performed during two time-slice integrations, are presented for the period 1960-90 and the 21st century (2070-2100), according to the “A1b” scenario defined by IPCC. This aims at addressing the feasibility of downscaling procedure in a regional basin, resolving features that are generally still not included when using global models and gaining useful indications on climate-change induced impacts on the wave climate and ocean circulation. For this purpose, a fully coupled version of the ROMS-SWAN model has been implemented, using interpolated meteorological forcings from the SINTA Project (SImulations of climate chaNge in the mediTerranean Area, a joint scientific cooperation of CMCC-INGV-Univ. of Belgrade). Within the Impacts on Soil and Water Division (ISC) of the CMCC, the numerical downscaling approach is integrated in a GIS-based Decision Support System (DSS) aimed at the integrated analysis of climate change impacts and risks on coastal zones at the regional, aimed at guiding decision-makers in the definition of adaptation strategies. Despite further experiments are needed to reach definitive results, the outcomes indicate the feasibility of the numerical downscaling approach; nevertheless, they also highlight uncertainties intrinsic to this approach that may be leading, at least at the present state of the art, to results of difficult interpretation. 2010-12-31T23:00:00Z http://hdl.handle.net/2122/7588 Title: Assimilating Along-Track Altimetric Observations through Local Hydrostatic Adjustment in a Global Ocean Variational Assimilation System Authors: Storto, A.; Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna, Italy; Dobricic, S.; Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna, Italy; Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Di Pietro, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: A global ocean three-dimensional variational data assimilation system was developed with the aim of assimilating along-track sea level anomaly observations, along with in situ observations from bathythermographs and conventional sea stations. All the available altimetric data within the period October 1992–January 2006 were used in this study. The sea level corrections were covariated with vertical profiles of temperature and salinity according to the bivariate definition of the background-error vertical covariances. Sea level anomaly observational error variance was carefully defined as a sum of instrumental, representativeness, observation operator, and mean dynamic topography error variances. The mean dynamic topography was computed from the model long-term mean sea surface height and adjusted through an optimal interpolation scheme to account for observation minus first-guess biases. Results show that the assimilation of sea level anomaly observations improves the model sea surface height skill scores as well as the subsurface temperature and salinity fields. Furthermore, the estimate of the tropical and subtropical surface circulation is clearly improved after assimilating altimetric data. Nonnegligible impacts of the mean dynamic topography used have also been found: compared to a gravimeter-based mean dynamic topography the use of the mean dynamic topography discussed in this paper improves both the consistency with sea level anomaly observations and the verification skill scores of temperature and salinity in the tropical regions. Furthermore, the use of a mean dynamic topography computed from the model long-term sea surface height mean without observation adjustments results in worsened verification skill scores and highlights the benefits of the current approach for deriving the mean dynamic topography. 2011-02-28T23:00:00Z http://hdl.handle.net/2122/7562 Title: Global ocean re-analyses for climate applications Authors: Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Di Pietro, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Storto, A.; Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna, Italy; Navarra, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: One of the main objectives of the global ocean modelling activities at Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC) is the production of global ocean re-analyses over multidecadal periods to reconstruct the state of the ocean and the large scale cir- culation over the recent past. The re-analyses are used for climate applications and for the assessment of the benefits of assimilating ocean observations on seasonal and longer predictions. Here we present the main characteristics of an optimal interpola- tion based assimilation system used to produce a set of global ocean re-analyses validated against a set of high quality in situ observa- tions and independent data. Differences among the experiments of the set are analyzed in terms of improvements in the method used to assimilate the data and the quality of observations them- selves. For example, the integrated ocean heat content, which can be taken as an indicator of climate changes, is examined to detect possible sources of uncertainty of its long-term changes. Global and basin scale upper ocean heat content exhibits warming trends over the last few decades that still depend in a significant way on the assimilated observations and the formulation of the background covariances. However, all the re-analyses show a global warming trend of the oceanic uppermost 700 m over the last five decades that falls within the range of the most recent observation-based estimates. The largest discrepancies between our estimates and observational based ones are confined in the upwelling regions of the PacificandAtlanticOceans.Finally,theresultsshow that the climatological heat and salt transports as a function of latitude also fall within the range of the estimates based on observations and atmospheric re-analyses. 2011-08-31T22:00:00Z http://hdl.handle.net/2122/7255 Title: Multidisciplinary Investigations at Panarea (Aeolian Islands) after the Exhalative Crisis of 2002 Authors: Bortoluzzi, G.; CNR-ISMAR; Aliani, S.; CNR-ISMAR; Ligi, M.; CNR-ISMAR; D'Oriano, F.; CNR-ISMAR; Ferrante, V.; CNR-ISMAR; Riminucci, F.; CNR-ISMAR; Carmisciano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cocchi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Muccini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Editors: Enrico Brugnoli, Giuseppe Cavarretta, Salvatore Mazzola, Fabio Trincardi, Mariangela Ravaioli, Rosalia Santoleri; Marine Research at CNR Abstract: Panarea and surrounding Islets form a volcanic edifice, that is part of the Eastern sector of the Aeolian Arc, Southern Tyrrhenian Sea. It is now considered inactive, since last documented activity is 20 Ka old. However, on 2002-11-03, gas started to flow violently from the seafloor in an area E of the Island, mainly along NE and NW structural lineaments, and lasting up to 2003-2004 with a consistent flux, orders of magnitude larger that ’steady-state’ fumarolic activity documented there in historical times. On the same period a strong effusive activity of Stromboli (10 NM to NNE) was present. Since then, several investigations have been conducted at sea and on land, with the aim of focusing on the problem of effusive activity at sea, mainly in the light of volcanic surveillance and risk. Among these investigations, some of which have been repeated over years, we present and discuss some data and results from: (a)visual inspection and sampling by divers and ROV, (b)GPS networks and mapping by multibeam and LIDAR, (c) oceanographical measurements by current meters and CTD, and water flux and dynamics measurements, (d)magnetic and gravimetric surveys, (e) multichannel reflection Seismic with OBS and land station networks. Data were used for compilation of high resolution bathymetric, magnetic and gravimetric maps, including the emerged and submerged portions of the edifice. 2011-10-31T23:00:00Z http://hdl.handle.net/2122/6919 Title: Impact of Multialtimeter Sea Level Assimilation in the Mediterranean Forecasting Model Authors: Pujol, M.-I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Dobricic, S.; CMCC; Pinardi, N.; Adani, M. Abstract: In this article the impact of multisatellite altimeter observations assimilation in a high-resolution Mediterranean model are analyzed. Four different altimeter missions [Jason-1, Envisat, Ocean Topography Experiment (TOPEX)/Poseidon interleaved and Geosat Follow-On] are used over a 7-month period (from September 2004 to March 2005) to study the impact of the assimilation of one to four satellites on the analyses quality. The study highlights three important results. First, it shows the positive impact of the altimeter data on the analyses. The corrected fields capture missing structures of the circulation, and eddies are modified in shape, position, and intensity with respect to the model simulation. Second, the study demonstrates the improvement in the analyses induced by each satellite. The impact of the addition of a second satellite is almost equivalent to the improvement given by the introduction of the first satellite: the second satellite’s data bring a 12% reduction of the root-mean-square of the differences between the analyses and observations for the sea level anomaly (SLA). The third and fourth satellites also improve the rms, with a more than 3% reduction for each of them. Finally, it is shown that Envisat and Geosat Follow-On additions to Jason-1 impact the analyses more than the addition of TOPEX/Poseidon, suggesting that the across-track spatial resolution is still one of the important aspects of a multimission satellite observing system. This result could support the concept of multimission altimetric monitoring done by complementary horizontal resolution satellite orbits. 2009-12-31T23:00:00Z http://hdl.handle.net/2122/6918 Title: Integration of Argo trajectories in the Mediterranean Forecasting System and the impact on the regional analysis of the Western Mediterranean circulation Authors: Taillandier, V.; Dobricic, S.; CMCC; Pinardi, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Testor, P.; Griffa, A.; Mortier, L.; Gasparini, G. P. Abstract: The impact of Argo float trajectory assimilation on the quality of ocean analyses is studied by means of an operational oceanographic model implemented in the Mediterranean Sea and a 3D-Var assimilation scheme. For the first time, both Argo trajectories and vertical profiles of temperature and salinity (TS) together with satellite altimeter data of sea level anomaly (SLA) are assimilated to produce analyses for short term forecasts. The study period covers 3 months during winter 2005 when four Argo trajectories were present in the northwestern Mediterranean Sea. The scheme is first assessed computing the misfits between observations and model forecast and analysis. The misfit statistics appear improved for float trajectories, while they are not degraded for the other assimilated variables (TS profiles and SLA). This indicates that the trajectory integration is consistent with the other components of the assimilation system and provides new information on horizontal pressure gradients. Comparisons between analyses obtained with and without trajectory assimilation suggest that trajectory assimilation can have an impact on the description of boundary currents and their instabilities, as well as mesoscale activity at regional scales. Changes are depicted by intermediate water mass redistributions, mesoscale eddy relocations, and net transport modulations. These impacts are detailed and assessed considering historical and simultaneous in situ data sets. The results motivate the integration of Argo trajectories in the operational Mediterranean Forecasting System. 2009-12-31T23:00:00Z