OA Earth-prints Repository
Not a member yet
16457 research outputs found
Sort by
CO2 Dipole Moment: A Simple Model and Its Implications for CO2-Rock Interactions
No full textCO2 is a widespread fluid naturally occurring within the Earth crust or injected in deep strata for technological issues such as Carbon Capture and Storage (CCS). At STP conditions, CO2 is a gas, with a net zero dipole moment. Growing pressures produce an increase in its density. The reduced intermolecular distance causes a variation in the molecular structure, due to the intensification of mutual interactions. Some published spot data reveal the departure from the planarity of the bond angle while others provide few values of the CO2 dipole moment. Based on a small amount of literature-measured angle values, it was possible first to extrapolate a correlation between bond angle and density (R2 = 0.879). By fixing the partial charges distribution, we present a simple model that allows the calculation of the CO2 dipole moment directly from the geometry of the molecule, in the range of 179–162 degrees, 1-degree step. Results give values up to about 1 D. Being aware that this model is qualitative, it gives, however, an explanation of the experimental reactivity, and it also provides a valid tool in identifying zones in the crust where these reactions are likely to occur efficiently. Finally, we hypothesise the role of dry CO2 in the carbonate formation through the interactions with the basalts.Published871TR. GeorisorseJCR Journa
How will climate change affect the isotope composition of meteoric water in the Mediterranean area?
No full textThe relationship between the isotopic composition of precipitation in the Mediterranean Sea, the atmospheric circulation patterns over the region and groundwater properties has been topic of investigation in recent years. Overall, the link between the isotopic composition of precipitation and the Mediterranean climate raises the question of how future climate change could affect the isotope ratios of precipitation and groundwater. Past and future atmospheric properties (i.e. humidity, evaporation, precipitation and winds) over the Mediterranean region can be used to investigate the past and possibly understand future characteristics of meteoric water isotope composition. In order to evaluate how the climate change will affect the isotope composition of meteoric water, we re-evaluated previous rain events in light of well-defined climate framework. The main objective is to retrieve information on the atmospheric circulation systems based on ERA5 reanalysis and relate climate features with the isotope composition of selected rain events. This will allow to identify the most appropriate parameters needed to constrain the circulation systems responsible for those events and their isotope composition. Preliminary results to infer scenario-based considerations on the evolution of the meteoric recharge will be shown and discussed.PublishedViennaOSA2: Evoluzione climatica: effetti e loro mitigazion
Particle classification in the LAGO water Cherenkov detectors using clustering algorithms
No full textThe Latin American Giant Observatory (LAGO) is a ground-based observatory studying solar or high-energy astrophysics transient events. LAGO takes advantage of its distributed network of Water Cherenkov Detectors (WCDs) in Latin America as a tool to measure the secondary particle flux reaching the ground. These secondary particles are produced during the interaction between the modulated cosmic rays flux and the atmosphere.
The LAGO WCDs are sensitive to secondary charged particles, high energy photons through pair creation and Compton scattering, and even neutrons thanks to, e.g., the deuteration of protons in the water volume. The pulse shape generated by these particles depends on several factors, such as the detector geometry, the water purity, the sensor response, or the reflectivity and diffusivity of the inner coating. Due to the decentralized nature of LAGO, these properties are different for each node. Additionally, the pulse shape depends on the convolution between the response of the central photomultiplier (PMT) to individual photons and the time distribution of the Cherenkov photons reaching the PMT. Typically, a WCD gives pulses with a sharp rise time (
10 ns) and a longer decay time (
70 ns).
In this work, the WCD data used is acquired using the original LAGO data-acquisition system that digitizes pulses at a sampling rate of 40 MHz and 10 bits resolution on time windows of 400 ns. Here, we apply unsupervised machine learning techniques to find patterns in the WCDs data and subsequently create groups, through clustering, that can be used to provide particle separation. We use data acquired from an individual WCD, showing that density-based clustering algorithms are suitable for automatic particle separation producing good candidate groups. Improved separation would help LAGO to reconstruct in situ the properties of primary cosmic rays flux. These results open the possibility to deploy machine learning-based models in our distributed detection network for onboard data analysis as an operative prototype, allowing detectors to be installed at very remote sites.Published168557JCR Journa
Song Notes and Patterns of the Mediterranean Fin Whale (Balaenoptera physalus) in the Ionian Sea
No full textThe Mediterranean fin whale emits two types of 20-Hz calls, known as “classic” and “backbeat”, that can be produced in irregular series or in patterned sequences called songs. The analysis of songs is recognized as a meaningful approach to study baleen whales and can be used to investigate populations’ identities. Mediterranean fin whale songs have been studied previously, but only in the western Mediterranean Sea. This work describes the structure of the songs recorded in the Ionian Sea. The inter-note intervals and the alternation of 20-Hz note types were considered to assess the occurrence of recurring patterns. Differences between patterned songs and irregular sequences were also investigated. Acoustic data were sampled continuously for about 10 months by the cabled observatory NEMO-SN1, deployed at 2100 m depth, 25 km offshore Catania; 28 call sequences were isolated and 10 of these were classified as either patterned songs or irregular sequences. Significant differences were observed in the spectral features of classic notes between songs and irregulars; four-note patterns were found repeatedly over different months, indicating a regular structure in detected songs. This work establishes a reference to interpret Mediterranean fin whale songs, and to assess the acoustic behavior of the population.Published2057OSA4: Ambiente marino, fascia costiera ed Oceanografia operativaJCR Journa
Coastal reconstruction of Pyrgi (Santa Severa, Rome), an ancient maritime Etruscan settlement
No full textHistorical sources report that the ancient Etruscan harbour of Pyrgi became important starting from the
7th century, when Caere already exercised almost unconditional control over the Tyrrhenian Sea. It was emporia harbours category of the 4th and 5th centuries suitable for receiving a great number of ships.
Results obtained by gravity survey identify flysch bedrock trend and the Plio-Holocene deposits therefore geographical conformation of an ancient natural landing of the area, characterized by promontories and paleo-valleys different from the contemporary morphology. It is the result of natural processes, sea level changes and coastal erosion, and processes induced by anthropogenic activity: deforestation for ship building materials and for metallurgical activity. Denudation processes have affected the Tolfa Mts slopes and erosion sediment transport occurs in natural rivers, valleys and estuaries infilling, thus modifying the past coastal landscape environmental of the last 24 centuries.Published211-2207A. Geofisica per il monitoraggio ambientale2TR. Ricostruzione e modellazione della struttura crostaleN/A or not JC
Why (Still) Studying Turbulence in Fluids and Plasmas?
No full textTurbulence, a captivating and intricate phenomenon, continues to attract researchers across diverse scientific disciplines. Despite considerable efforts, turbulence remains a fascinating challenge and stands as one of the unsolved enigmas in classical physics. Researchers strive to unravel the underlying physical mechanisms and refine mathematical models to unlock a comprehensive understanding of this complex phenomenon. This paper delves into the reasons why the study of turbulence still persists for a long time, highlighting its history and fundamentals, wide-ranging applications, significance in environmental and climate sciences, and outstanding open challenges. Through these endeavors, the quest for unraveling the mysteries of turbulence promises to yield profound scientific insights and practical applications in the years to come.Publishede2023CN000215OSA2: Evoluzione climatica: effetti e loro mitigazioneN/A or not JC
Antarctic Bedmap data: Findable, Accessible, Interoperable, and Reusable (FAIR) sharing of 60 years of ice bed, surface, and thickness data
No full textOne of the key components of this research has been the mapping of Antarctic bed topography and ice thickness parameters that are crucial for modelling ice flow and hence for predicting future ice loss and the ensuing sea level rise. Supported by the Scientific Committee on Antarctic Research (SCAR), the Bedmap3 Action Group aims not only to produce new gridded maps of ice thickness and bed topography for the international scientific community, but also to standardize and make available all the geophysical survey data points used in producing the Bedmap gridded products. Here, we document the survey data used in the latest iteration, Bedmap3, incorporating and adding to all of the datasets previously used for Bedmap1 and Bedmap2, including ice bed, surface and thickness point data from all Antarctic geophysical campaigns since the 1950s. More specifically, we describe the processes used to standardize and make these and future surveys and gridded datasets accessible under the Findable, Accessible, Interoperable, and Reusable (FAIR) data principles. With the goals of making the gridding process reproducible and allowing scientists to re-use the data freely for their own analysis, we introduce the new SCAR Bedmap Data Portal (https://bedmap.scar.org, last access: 1 March 2023) created to provide unprecedented open access to these important datasets through a web-map interface. We believe that this data release will be a valuable asset to Antarctic research and will greatly extend the life cycle of the data held within it. Data are available from the UK Polar Data Centre: https://data.bas.ac.uk (last access: 5 May 2023). See the Data availability section for the complete list of datasets.Published2695–2710OSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
A Joint Multifractal Approach to Solar Wind Turbulence
No full textPrevious studies have shown that solar wind, a plasma medium with turbulent dynamics,
exhibits anomalous scaling features, i.e., intermittency, in the inertial domain. This intermittent nature
has primarily been investigated through the study of the scaling features of the structure functions
of single quantities. We use a novel approach based on joint multifractal analysis in this study to
simultaneously investigate the scaling characteristics of both the magnetic field and the plasma
velocity in solar wind turbulence. Specifically, we focus on the joint multifractal behavior of magnetic
and velocity field fluctuations in both fast and slow solar wind streams observed by the ESA-Ulysses
satellite, with the goal of identifying any differences in their joint multifractal characteristics.Published748OSA3: Climatologia e meteorologia spazialeJCR Journa
Observing Etna volcano dynamics through seismic and deformation patterns
No full textGeophysical data provide the chance to investigate a volcano's dynamics; considerable information can especially be gleaned on the stress and strain patterns accompanying the internal processes and the effect of magma ascent on the main structures triggering earthquakes. Here, we analysed in detail the seismicity recorded over the last two decades on Etna volcano (southern Italy), focusing on earthquakes distribution and focal mechanism clustering; the ground deformation pattern affecting the volcanic edifice with the inflation and deflation phases was also examined. Analysed data were compared in order to shed light on possible relationships with the volcanic activity and to better understand the internal dynamics of the volcano over time. Significant steps during or shortly before major eruptions in the seismic strain release and ground deformation temporal series highlight a straightforward relationship between seismicity occurring at shallow level, inflation/deflation and volcanism. Furthermore, at depths greater than 5-7 km, down to about 20 km, the orientation of the P- and T-axes clearly indicate the existence of a pressure source in the central part of the volcano. All the results underline that the stress field related to the volcano plumbing system interferes with the regional field, partly overriding it.INGV-Ricerca Libera 2021
INGV-IMPACTPublished12951OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Unveiling Geomagnetic Reversals: Insights From Tipping Points Theory
No full textThe geomagnetic field shows aperiodic reversals and excursions separated by stable polarity periods. Although the exact mechanisms responsible of reversals are still debated, several models of different complexity have been proposed. Here we use, for the first time, a different and novel approach based on the theory of tipping points to detect and characterize geomagnetic reversals occurred during the period 25–36 millions years ago by using a high-resolution magnetostratigraphic study conducted on a sedimentary section located on Maud Rise in the Southern Ocean. We detect a critical threshold for an early warning indicator of the occurrence of a polarity reversal below which a polarity reversal starts. Through the proper use of this early warning indicator we build up a simple non-autonomous stochastic model to describe the main features of polarity reversals. This approach could be helpful for building up a novel framework for paleomagnetic studies.Publishede2023GL105646OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioJCR Journa