9762 papers found
The Argo Float programme is a valuable instrument for monitoring the deep sea at global scale in space and time. Argo Floats equipped with imaging devices are candidate to become a new monitoring tool for studying macro- and mega- fauna in large areas and for extended periods, potentially providing monitoring results never attained before.
The aim of this paper is to give an overview of the various elements that contribute to the observation of Sea Surface Temperature in Italian Seas. Long term time series are collected since the 19th century but are affected by a large systematic errors. Despite the lack of accuracy, their contribution to the analysis of trends is fundamental into the climate change context. On the other hand, recent systematic observations are more accurate and continuous in space and time. Short term time series better define the status of the temperature during the last years in term of variability and...
"UNAC-LOW" is an ongoing project under EURAMET's EMPIR programme whose aim is to develop the European metrological capacity in underwater acoustics for the calibration of hydrophones and autonomous noise recording systems for frequencies below 1 kHz. The project will provide an improved framework to underpin the absolute measurement of underwater sound in support of regulation and EU Directives for which traceability is currently lacking. Methods for the calibration of hydrophones and autonomous recording systems in the frequency range from 20 Hz to 1 kHz will be developed and validated by...
The Italian Fixed-point Observatory Network (IFON) integrates well-established ocean infrastructures managed by various national research institutions (CNR, OGS, and ENEA). The implementation of this network was one of the aim of the SP5-WP3 of the Flagship Project RITMARE. In the first four years of the project, the state of art of the 15 operative sites has been completed and 2 more stations are operative from 2015-2016. For each site, the technical characteristics and methods of transmission have been described, and for some sites, several upgrades were accomplished in order to develop,...
The CALYPSO HF radar network is a permanent and fully operational observing system currently composed of four CODAR HF stations. The system is providing real-time hourly maps of sea surface currents and wave data in the Malta-Sicily Channel since 2012. The present work aims to compare significant wave height from HF Radar, numerical models and satellite altimeter data. This is the first time that this set of wave data are analysed since the four HF radars were installed between 2012 and 2015. Results suggest that CODAR HF Radar wave data are a reliable source of wave information even in case...
Multiparametric cable video-observatories can offer a great opportunity for the simultaneous monitoring of biotic and abiotic components of an ecosystem, responding to the monitoring strategic needs of the EU Marine Strategy Framework Directive (MSFD). Here, we used images and oceanographic/atmospheric data provided by Northwestern Mediterranean OBSEA cabled observatory as EMSO shallow water (i.e. 20 m depth) testing-site to highlight seasonal variations in coastal fish assemblages and identify the key environmental drivers. Significant variation was observed in fish composition across the...
The Guidance and Control system is a critical part of the design of a drone. This paper explains the study of a high accuracy attitude system for the SQUID TUG, a Tailless Underwater Glider drone. As the vehicle does not have movable surfaces, the entire manoeuvring system is geared to the buoyancy system and the centre of gravity displacement. We will examine the control system for a tailless AUV (Autonomous Underwater Vehicle) without any movable control surfaces embedded in the hydrodynamic flow whose actuators may require "waterways" through the hull.
The aim of this paper is to define performances and metrological characteristics of simple and economical photomodelling techniques for boat shape measurements, an innovative technique developed recently. Compared with the technique based on a Creaform ScanGo 50 structured light 3D scanner with metrological certification, the investigation wants to verify the potential of this recent technique and to be as reference for photomodelling performance metrological evaluation.
Vertical geothermal exchangers (geothermal probes) are very complex, especially in presence of diverse and possible lithotypes which values of thermal conductivity expressed in W/mk, are necessary for the determination of thermal resistance; they also influence the design of the thermal probe. One the simplified methods to design thermal probes is based on its capability to interact with lithostratigraphy that permits to know the thermal conductivity. The efficiency of the thermal probe is highly related to the nature of the filling fluid because it steers the thermal exchange with the soil...
The effects of landslide and erosion can be detected and monitored by airborne-based systems, and in particular by satellite using InSAR (interferometry by Synthetic Aperture Radar). The interferogram is applied here as an innovating tool to predict mid and long term effects of landslide and erosion. SAR images are generally found to be contaminated with a special type of highly unordered and chaotic noise pattern termed as speckle noise. When an object is illuminated by a coherent source of radiation and the object has a surface structure that is roughly of the order of the wavelength of...