Bianchi, Cesidio

One 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.

Nell’ambito del progetto EDISECUR, finanziato della regione Lazio, è stato sviluppato un prototipo di telesensore infrasonico, TIS, a tracciamento di speckle per la misura della velocità angolare, delle frequenze fondamentali e delle armoniche di una superficie sottoposta a oscillazioni. Il TIS si presta particolarmente per il rilevamento e il monitoraggio nel tempo degli edifici, ponti e altri manufatti. Conoscere lo stato vibrazionale di queste strutture può essere d’interesse sia per la loro caratterizzazione dinamica che per la sicurezza. Questo prototipo, sufficientemente compatto, si presta a una misura immediata della velocità angolare e, con semplici operazioni, si possono dedurre spostamenti e accelerazioni angolari. Dalle grandezze angolari e dalla conoscenza geometrica della superficie, tramite alcuni schemi ed esempi, si mostra come sia possibile determinare anche altri parametri cinematici lineari. Il telesensore può essere impiegato nelle misure delle vibrazioni di superfici a lunga distanza di varia natura, anche laddove non fosse possibile accedere per eseguire una misura diretta. Lo strumento copre un campo di frequenze fino alle decine di Hz, ha una sensibilità e una dinamica tale da rilevare le vibrazioni indotte dal rumore industriale, dal traffico, dal vento e altro. Questo lavoro è principalmente rivolto alle applicazioni del TIS nel rilevamento delle vibrazioni delle strutture ed è in questo ambito che vengono spiegate le modalità, i limiti e i vantaggi del suo impiego insieme agli errori insiti nella tecnica di misura. Dato che il TIS misura un movimento relativo tra lo stesso strumento e la superficiebersaglio, sono stati valutati gli errori delle vibrazioni dovute alla microsismicità e altre cause ambientali. Vengono infine riportati due preliminari esempi di misura su una struttura edile.

On 25 May 1928 the airship “Dirigibile Italia” during its return trip to the base in NyAlesund, after overflying the North Pole, shipwrecked on the ice‐pack in a region at about 400 km northeast of Svalbard Islands. Survivors, by using a portable high frequency (HF) radio transmitter, tried unsuccessfully to send SOS messages and to establish a radio link with the ship “Città di Milano” of the Italian Navy, closely anchored at King's Bay. Only after 9 days of repeated radio‐distress transmissions, a Russian radio amateur close to the town of Arkhangelsk about 1,900 km away was able to receive the messages launched by the survivors and raise the alarm. This paper aims at giving a retrospective analysis of the ionospheric and geomagnetic conditions of that epoch in order to explain the HF radio communications problems encountered by the survivors. The International Reference Ionosphere model has been applied, and early geomagnetic measurements have been evaluated, to come up with theories explaining the events. We assert the HF transmission difficulties were associated with the “radio silent” or “dead zones” associated with F‐region propagation. These may have been exacerbated by solar and geomagnetically disturbed conditions of the days immediately following the airship wreck.

We propose an optimal control problem to determine the best aeration strategy for aerobic biodegradation in a composting cell. The goal is to minimize the deviation of the oxygen level from its reference value for the entire duration of the biodegradation process. The mathematical model includes several chemical phenomena, like the aerobic biodegradation of the soluble substrate by means of a bacterial biomass, the hydrolysis of insoluble substrate and the biomass decay. The oxygen and the optimal mechanical aeration time profiles are obtained and discussed. Finally, the plant performance is evaluated in absence and presence of external aeration by means of several specific indices.

We introduce a mathematical model for the composting process in biocells. The model includes several phenomena, like the aerobic biodegradation of the soluble substrate by means of a bacterial population, the hydrolysis of insoluble substrate, and the biomass decay. We investigate the best strategies to reduce substrate components in minimal time by controlling the effects of cell oxygen concentration on the degradation phenomenon. It is shown that singular controls are not optimal for this model and the optimal control time profiles are of bang or bang-bang type. The occurrence of switching curves is discussed. In the case of a bang-bang control we prove that optimal control profiles have a unique switching time and the corresponding switching curve is determined.

Following the Mw 6.3 earthquake that hit the city of L'Aquila (Central Italy) on the 6th April 2009, a scientific project was proposed with the aim of investigating the Abruzzo area by means of different disciplinary approaches including geological, seismic, and physical studies. Electromagnetic field monitoring in the 0.01–500 mHz frequency band was implemented for the investigation of electromagnetic signals in the Earth's crust. Three measurement stations were installed in a tectonically active area with a radius of about 10 km. Each site was equipped with a fluxgate magnetometer with a 1 Hz sampling rate. This paper describes a long term geomagnetic deep sounding analysis for each site, aimed at investigating the dimensionality of the electrical structure of the subsurface in the area involved in the survey. According to a very simplified RL circuit model, some electrical properties of subsurface are also deduced.

Vertical sounding is a widely used technique to obtain ionosphere measurements, such as an estimation of virtual height versus frequency scanning. It is performed by high frequency radar for geophysical applications called "ionospheric sounder” (or "ionosonde”). Radar detection depends mainly on targets characteristics. While several targets behavior and correspondent echo detection algorithms have been studied, a survey to address a suitable algorithm for ionospheric sounder has to be carried out. This paper is focused on automatic echo detection algorithms implemented in particular for an ionospheric sounder, target specific characteristics were studied as well. Adaptive threshold detection algorithms are proposed, compared to the current implemented algorithm, and tested using actual data obtained from the Advanced Ionospheric Sounder (AIS-INGV) at Rome Ionospheric Observatory. Different cases of study have been selected according typical ionospheric and detection conditions.

The ionosphere affects the electromagnetic wave propagation and then its study is important for Earth-Earth, satellite-Earth, and satellite-satellite communication purposes. Diffractive and refractive processes due to irregular electron density structures cause signal fluctuations that can disrupt satellite-ground communications and represent a hazard for navigation systems. The study and the real-time monitoring of the ionosphere are important for Space Weather purposes. The ionospheric vertical sounding is described, together with the automatic scaling of the ionograms.

The IONORT-ISP system (IONOspheric Ray-Tracing – IRI-SIRMUP-PROFILES) was recently developed and tested by comparing the measured oblique ionograms over the radio link between Rome (41.89ºN, 12.48ºE), Italy, and Chania (35.51ºN, 24.02ºE), Greece, with the IONORT-ISP simulated oblique ionograms (Settimi et al., 2013). The present paper describes an upgrade of the system to include: a) electron-neutral collision have been included by using a collision frequency model that consists of a double exponential profile; b) the ISP three dimensional (3-D) model of electron density profile grid has been extended down to the altitude of the D-layer; c) the resolution in latitude and longitude of the ISP 3-D model of electron density profile grid has been increased from 2°x2° to 1°x1°. Based on these updates, a new software tool called IONORT-ISP-WC (WC means with collisions) was developed, and a database of 33 IONORT-ISP-WC synthesized oblique ionograms calculated for single (1-hop paths) and multiple (3-hop paths) ionospheric reflections. The IONORT-ISP-WC simulated oblique ionograms were compared with the IONORT-IRI-WC synthesized oblique ionograms, generated by applying IONORT in conjunction with the International Reference Ionosphere (IRI) 3-D electron density grid, and the observed oblique ionograms over the aforementioned radio link. The results obtained show that (1) during daytime, for the lower ionospheric layers, the traces of the synthesized ionograms are cut away at low frequencies because of HF absorption; (2) during night-time, for the higher ionospheric layers, the traces of the simulated ionograms at low frequencies are not cut off (very little HF absorption); (3) the IONORT-ISP-WC MUF values are more accurate than the IONORT-IRI-WC MUF values.

The Earth is surrounded by the ionosphere and magnetosphere that can roughly be seen schematically as two concentric shells. These two composed and inhomogeneous structured shells around the Earth selectively affect electromagnetic (EM) waves propagation. Both ionosphere and magnetosphere interact also with particles and waves coming from external sources, generating electromagnetic phenomena that in turn might become sources of EM waves. Conversely, EM waves generated inside the ionosphere remain confined at various altitudes in this region, up to a socalled critical frequency limit, depending on frequency, EM waves can escape out of the ionosphere and magnetosphere or get through. The EM waves generated inside the magnetospheric cavity mainly originate as a result of the electrical activity in the atmosphere. It is well known that also man-made sources, now widely spread on Earth, are a fundamental source of EM waves; however, excluding certain frequencies employed in power distribution and communication, man-made noise can be dominant only at local scale, near their source. According to recent studies, EM waves are also generated in the Earth’s lithosphere; these waves were sometimes associated with earthquake activity showing, on the Earth’s surface, intensities that are generally orders of magnitude below the background EM noise. In this review paper, we illustrate EM waves of natural origin and discuss their characterization in order to try discriminate those of lithospheric origin detectable at or near the Earth’s surface.