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ANTARCTICA

22010 record(s)
 
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From 1 - 10 / 22010
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    This research addressed a feasibility study for a remote monitoring system based on acoustic tomography to be used in antarctic regions. The analysis of data collected during PNRA oceanographic campaigns provided the environmental scenarios and the oceanographic processes to be successfully monitored by means of acoustic tomography and the appropriate information and data to initialize the tomographic processor. The case studies regarded High Salinity Shelf Water formation process in Terra Nova Bay polynya. The simplified but realistic environmental scenario considered a 1000 m deep area with a flat bottom. The dense water formation area was defined by a strong vertical salinity gradient in the surface, while in the areas outside, temperature and salinity were considered constant in depth leading to an almost linear increasing sound speed profile. At this stage of study, the possible presence of ice layer covering the area is not expected to have any significant effect on the propagation prediction, so it was not considered. Simulations were carried out with a beam model (Bellhop) which is well suited for active sonar modelling and ocean acoustic tomography in a range dependent environment. Each simulation involves the use of an acoustic source and a receiving station (tomographic pair) consisting of a vertical array of hydrophones. By measuring the travel time relative to different scenarios, the analysis aimed at understanding if the detection of the oceanographic phenomenon is feasible. In particular, the study aimed at determining the best compromise between acoustic frequencies, sensors number and geometrical configuration, in order to achieve the desired spatial-temporal resolution useful to detect the presence of dense water masses. An acoustic system configuration consisting of an acoustic source transmitting a pulse with a carrier frequency of 10 kHz, and of a receiving array made of 6 hydrophones resulted to be appropriate, while the minimum size of detectable Dense Water Mass is 0.5 km. In particular, the conducted sensitivity study evidences that the measure of travel time of acoustic rays can be successfully exploited to detect the presence of a dense water mass in a polynya area Acoustic tomography thus provides “images” of wide areas in the inner ocean for long periods and with an high temporal resolution; in addition it permits to reconstruct the sound speed field even in the upper layers where direct measurements cannot be performed as instruments are at risk of damage. It can then be consider a powerful mean of observation that well integrates conventional in situ measurements. Preliminar investigation on the applicability of this methodology in Terranova Bay polynya demonstrated that it is able to resolve the vertical structure of water column with a good precision.

  • The DoCTOr (Dome C Tropospheric Observer) project aims to establish an integrated monitoring system to measure simultaneously, continuously and with a high temporal resolution the water vapor and temperature vertical profiles and the radiative exchanges vs. altitude. The monitoring will enable us to detect both long-term trends and fast-evolving phenomena, the latter useful in the interpretation of the causes of the first. This task is performed mainly through remote sensing techniques, allowing for the study of a highly unperturbed atmospheric sample. The integration of all the deployed instrumentation in a single acquisition system simplifies greatly the data analysis needed to retrieve the final products: The REFIR-PAD spectroradiometer (already operating in dome C since 2011) will provide spectrally-resolved atmospheric downwelling radiances in the mid to far-infrared spectral range, while a laser diode based profiler will characterize the microphysics state of the first 3 km of the atmosphere.A real-time data analysis system based on an atmospheric radiative transfer model will then retrieve from the acquired data the temperature and water vapor profiles and the cloud optical thickness in almost all weather conditions found at Dome C, with a temporal resolution of about 10 minutes.

  • During austral summer1994/95, the National Institute of Oceanography and Applied Geophysics - OGS, on board the research vessel OGS-Explora, conducted marine geological and geophysical surveys along the Antarctic Peninsula. The ANGELINA (ANtarctic GEophysical Long range INternational Acquisition) programme was a seismic exploration cruise in the Adelaide Fracture Zone on the Pacific Margin, near Marguerite Bay and Adelaide Island; data were collected between longitude 68 and 74 degrees West, and latitude 66 and 69 degrees South. During this programme 610 km of 20-fold multichannel seismic reflection (MCS) data, 20 second records, 4 ms sample rate, were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with a total volume of 75 litres fired every 75 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 10 m. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientist on this programme was: Michele Pipan of the Dipartimento di Scienze Geologiche Ambientali e Marine of the Università di Trieste, via Weiss n.2, 34127 Trieste, Italy. Processing of the data generally followed a conventional sequence: Reformat, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Stack, Mixing, Filter, and Dynamic trace equalisation.

  • During austral summer1994/95, the National Institute of Oceanography and Applied Geophysics - OGS, on board the research vessel OGS-Explora, conducted marine geological and geophysical surveys along the Antarctic Peninsula. The ANGELINA (ANtarctic GEophysical Long range INternational Acquisition) programme was a seismic exploration cruise in the Adelaide Fracture Zone on the Pacific Margin, near Marguerite Bay and Adelaide Island; data were collected between longitude 68 and 74 degrees West, and latitude 66 and 69 degrees South. During this programme 610 km of 20-fold multichannel seismic reflection (MCS) data, 20 second records, 4 ms sample rate, were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with a total volume of 75 litres fired every 75 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 10 m. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientist on this programme was: Michele Pipan of the Dipartimento di Scienze Geologiche Ambientali e Marine of the Università di Trieste, via Weiss n.2, 34127 Trieste, Italy. Processing of the data generally followed a conventional sequence: Reformat, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Stack, Mixing, Filter, and Dynamic trace equalisation.

  • The HF radar denominated Dome C East (DCE) emits pulses of HF waves (8–20 MHz) which are refracted in the ionosphere and can be back-scattered by field aligned decameter scale irregularities of the electron density at distances ranging from 180 to 3550 km from each radar and at heights between 100 and 400 km. The radar signals are steered in 16 emission beams, separated by 3.3 degrees, in an azimuthal interval of 52 degrees, usually swept in 2 minutes. The signals are emitted according to multi-pulse sequences that allow the real-time acquisition of the autocorrelation function of the back scatter echoes, from which the reflected power, the VD Doppler velocity of the irregularities, and the spectral width can be calculated for each distance-azimuth cell. VD coincides with the velocity of the plasma along the line of sight. DCE is part of the Super Dual Auroral Radar Network (SuperDARN). In SuperDARN, pairs of radars, typically located at 2000 km distance and oriented so that their beams cross each other over the region to be studied, are used to get the velocity vector in two dimensions. DCE forms a common-volume pair with the SuperDARN South Pole radar (U.S.). SuperDARN radars are devoted to the study of ionosphere, between 100 and 400 km from ground, in the polar, auroral and medium latitude regions. The SuperDARN and DCE scientific objectives span from fundamental plasma physics to space weather in the framework of Sun-Earth relations. Italy participates in the SuperDARN international network also with the Dome C North radar(DCN), installed at the Concordia station in January 2019 and operative since then.

  • During austral summer1994/95, the National Institute of Oceanography and Applied Geophysics - OGS, on board the research vessel OGS-Explora, conducted marine geological and geophysical surveys along the Antarctic Peninsula. The ANGELINA (ANtarctic GEophysical Long range INternational Acquisition) programme was a seismic exploration cruise in the Adelaide Fracture Zone on the Pacific Margin, near Marguerite Bay and Adelaide Island; data were collected between longitude 68 and 74 degrees West, and latitude 66 and 69 degrees South. During this programme 610 km of 20-fold multichannel seismic reflection (MCS) data, 20 second records, 4 ms sample rate, were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with a total volume of 75 litres fired every 75 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 10 m. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientist on this programme was: Michele Pipan of the Dipartimento di Scienze Geologiche Ambientali e Marine of the Università di Trieste, via Weiss n.2, 34127 Trieste, Italy. Processing of the data generally followed a conventional sequence: Reformat, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Stack, Mixing, Filter, and Dynamic trace equalisation.

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    Since 1998, ENEA (Italian National Agency for New Technology, Energy and the Environment) has been carrying on researches to develop a plant based greenhouse facility for producing plant fresh food at the Italian bases of TNB (Terra Nova Bay) and Dome C (Concordia base) in Antarctica. Accordingly, at the base TNB “Mario Zucchelli” was installed a sustainable closed greenhouse facility PULSA (Plant-based Unit for Life Support in Antarctica). PULSA has been in operation during four campaigns in Antarctica. 1) A complete automatic hydroponics system for plant cultivation in artificial environmental (C.H.G.S., Closed Hydroponic Greenhouse System); 2. A closed module PULSA Unit. A prototype greenhouse module has been conceived and designed as a transportable unit made of a standard container, dimensions of 6055 (l)*2435(w)*2585(h) mm. The installed microclimate conditioning unit included an air heater of about 6.0 kW which can also act as inside air cooling as well as dehumidifier for removing the internal humidity (up to 2.5 kg/h of water) by forcing the air into a drying service. An air ventilation device composed of two fans each of 400 W and air capacity exchanging of 1200 m3/h was also installed to keep necessary air exchange and CO2 concentration. 3) A treating and recycling wastes unit for the purification of water and for the recycling of residual biomass wastes from the hydroponic cycles, 4) A complete automated and remote-controlling system for the germination and the production of the plantlets (Box-Nursery); 5) A simulator for the growth and the yield production of lettuce (SLS) in function of the temperature and the light applied to the crops. Other prototypes still under developing are: a) the multilevel hydroponics design; b) the solar photovoltaic system of 1.1 kWp, to optimize the yield and the autonomy of the enclosed growing volume using artificial and/or Light Emitting Diodes (LEDs) as light sources for plant crop growth. Considerations and comments are reported on the on-going challenge to use PULSA as scientific platform for implementing activities of research and demonstration on plant growth technologies for Space.

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    It is a program that, by means of surface crossings thousands of kilometers long, collects information on the behavior of the ice sheet and the related changes in the global sea level as a result of climatic and environmental changes over the last 200 years. Aims of the projects are: Determine the environmental variability in Antarctica over the last 200 yrs, and where the data are available the last 1000 years. Environmental proxies could include: sea ice variation, ocean productivity, anthropogenic impacts; and other, extra-Antarctic continental influences

  • The HF radar denominated Dome C North (DCN) emits pulses of HF waves (8–20 MHz) which are refracted in the ionosphere and can be back-scattered by field aligned decameter scale irregularities of the electron density at distances ranging from 180 to 3550 km from the radar and at heights between 100 and 400 km. The radar signals are steered in 16 emission beams, separated by 3.3 degrees, in an azimuthal interval of 52 degrees, usually swept in 2 minutes. The signals are emitted according to multi-pulse sequences that allow the real-time acquisition of the autocorrelation function of the back scatter echoes, from which the reflected power, the VD Doppler velocity of the irregularities, and the spectral width can be calculated for each distance-azimuth cell. VD coincides with the velocity of the plasma along the line of sight. DCN is part of the Super Dual Auroral Radar Network (SuperDARN). In SuperDARN, pairs of radars, typically located at 2000 km distance and oriented so that their beams cross each other over the region to be studied, are used to get the velocity vector in two dimensions. DCN forms a common-volume pair with the SuperDARN Zhongshan radar (China). SuperDARN radars are devoted to the study of ionosphere, between 100 and 400 km from ground, in the polar, auroral and medium latitude regions. The sscientific objectives of SuperDARN and DCN span from fundamental plasma physics to space weather, in the framework of Sun-Earth relations. Italy participates in the SuperDARN international network also with the Dome C East (DCE) radar,installed at Concordia in 2013 and operative since then.

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    The TALos Dome Ice CorE (TALDICE) is a European ice core research project (Italy, France, Germany, Switzerland, United Kingdom) aimed at retrieving an ice core reaching back through the previous two interglacials (about 250,000 years), from a peripheral dome of East Antarctica, and want to reconstruct a reliable chronology, thanks to the presence of numerous layers of volcanic dust given the proximity of several volcanoes. Talos Dome is an ice dome (159°11'E - 72°49'S, 2316 m asl) on the edge of the East Plateau of Antarctica, about 290 km from the Southern Ocean, 250 km from the Ross Sea, 275 km from Mario Zucchelli Station, 550 km North of Taylor Dome , 1500 km NW of Simple Dome, and 1100 km East of Dome C. The TALDICE project started in the field in November 2004 and ended on December 23, 2007, at the final depth of 1620.20 m. Ice Thickness 1795 m Mean annual temperature -41°C Mean annual atmospheric air pressure 721±10 hPa Ice velocity 0.14 m yr-1