SENAT
Report n° 230 (2006-2007) by M. Christian GAUDIN, Senator (for the parliament office for the evaluation of scientific and technological choices)
Disponible au format Acrobat (12 Moctets)
IV. OBSERVING THE EARTH, OBSERVING THE UNIVERSE
The polar regions, particularly Antarctica, are extremely important places for the observation of both the Earth and outer space.
A. OBSERVATORIES FOR THE EARTH AND THE UPPER ATMOSPHERE
France maintains several observatories in the polar regions and carries out regularly-scheduled missions.
1. Seismology
Seismological observations are carried out by the University of Strasbourg I, under the direction of Michel Cara.
In Adélie Land, for the past 40 years, in the Kerguelen Archipelago since 1983, in Crozet and in Amsterdam, these activities are carried out by an ORE (environmental research observatory).
The objective is to make very-wide-frequency-band and wide-dynamic-range measurements of ground movements. These observations are carried out continuously. Their stability and homogeneity are essential for their scientific utility.
The observatories are part of an international network and the collected data is made available to the international scientific community.
These stations are also extremely valuable in providing early warnings of tidal waves in the Indian Ocean .
The French Atomic Energy Commission (CEA) also maintains observatories as part of the Nuclear Non-Proliferation Treaty, so as to be able to detect any nuclear testing.
The current objective is to install an international seismology station at Concordia , so as to complete the network in an area in which very little data is available. This station should allow scientists to increase their understanding of the Earth's structure and earthquakes. An antenna of seismometers will be installed to observe seismological phases of little energy. Indeed, Dome C is particularly interesting to study the propagation of seismic waves along the North-South axis, because it is more rapid than along the equator due to the action of the Earth's core.
In addition, these stations would study - in partnership with Australia and the United States within the framework of the GAMSEIS project - the bedrock and, in particular, the Gamburtsev sub-glacial mountain chain, because the glaciers perhaps originated from this zone 25 to 30 million years ago.
To this end, the Australians and Americans would set up 25 autonomous stations, to be extended by some ten more stations towards Concordia. They must, of course, be sufficiently energy efficient to continue functioning during the winter months, which is technically very difficult. They could therefore be equipped with small wind turbines.
2. Measuring gravity and terrestrial magnetism
The University of Strasbourg I is also responsible for the monitoring of terrestrial magnetism and gravity.
In the Kerguelen Islands, Crozet, Amsterdam and Adélie Land, absolute measurements are carried out of the terrestrial magnetic field and of its variations. These measurements are made so as to better understand our planet's interior. They are transmitted around the world via the Intermagnet network . Dumont d'Urville is located near the magnetic pole, where the terrestrial field lines are vertical. In addition, the magnetic pole is moving rather rapidly north (it was located in the continent's interior in the middle of the 19th century). It is therefore very interesting to monitor it, given the fact that the magnetic poles have already been reversed several times in the Earth's history.
A station should be constructed on Dome C and used in collaboration with the Instituto Nazionale di Geofisica y volcanologia (INGV) in Rome. The objective is to have an international station that can be integrated into the Intermagnet network.
A temporary research programme is also aimed at measuring the absolute gravitational field in the sub-Antarctic islands and Antarctica thanks to a portable absolute gravimeter. This should allow for maregraphic measurements to be made and contribute to our understanding of the local geoid 18 ( * ) . It should also allow for a better appreciation of inter-annual variations and their comparison to measurements made from space.
3. Studying the stratosphere and monitoring the ozone layer
The discovery of the hole in the ozone layer in 1985 at Halley Bay by Joe Farman, Brian Gardiner and Jon Shanklin (see Farman et al, Nature , 1985) opened up an entire field of research, seeking both to measure this hole and to understand the mechanisms in ever greater detail.
· Quantifying the hole in the ozone layer
Since 1985, the hole in the stratospheric ozone layer 19 ( * ) has been a recurring, seasonal (austral spring) phenomenon. The ozone layer can decrease by 60-70% above the Antarctic.
The mechanisms resulting in the ozone-layer hole are now well known:
- a rise in the concentration of halogenated products in the strato-sphere over a long period of time;
- polar masses isolated in the wintertime because of the vortex (see the Vorcore project below);
- an intense cooling (temperatures below - 80° C);
- the activation of chlorine-containing compounds;
- a 4-5% loss per day of ozone starting in September, leading to the total or near-total disappearance of ozone at an altitude of between 14 and 22 km.
Inter-annual variability in the ozone-layer hole
Source: Sophie Godin-Beekmann (IPSL-SA, CNRS-UMPC-UVSQ)
France is part of the international surveillance network via an ORE (environmental research observatory) placed under the direction of the Service d'Aéronomie (IPSL-UPMC-CNRS). This scientific network was created following the signature of the Montreal Protocol in 1987 , which organizes the return of CFC 20 ( * ) emissions to their natural level.
The hole in the ozone layer can have an important impact, because it provokes an increase in the amount of UV rays that reach Earth, causing skin cancers, cataract, immunitary problems and damage to all living organisms.
The measures carried out by the researchers, therefore, seek to monitor the evolution of this phenomenon and anticipate its reduction. They must allow scientists to measure the impact of the Montreal Protocol and, taking into account its success, the other international agreements which strengthened it.
Expected evolution in the ozone-layer hole over the Antarctic
Source: Sophie Godin-Beekmann (IPSL-SA, CNRS-UMPC-UVSQ)
· Understanding the mechanisms
The Vorcore project is a major research project carried out in France on the lower Arctic and Antarctic stratosphere using long-lasting sounding balloons.
The objective of the Vorcore project is to study the dynamics of the Antarctic vortex using sounding balloons to understand the formation of the ozone hole during the austral spring, by measuring the impermeability of the polar vortex and therefore its small-scale porosity.
It is a good example of the complementarity of Arctic and Antarctic research . A series of tests was carried out in the Arctic between 2000 and 2002 and a measurement programme was carried out in September 2005 from the McMurdo American research station.
Therefore, it is also a good example of international cooperation and the quality of relations maintained between several partners. Indeed, the NSF accepted to bring nine French researchers to the American base during the first rotation at the end of September. Eight other stations accepted to carry out balloon launches coupled with the passing of the Vorcore balloons to complete the measurements.
The Arctic programmes of 2000 to 2002 were carried out from the Swedish Kiruna base. They had difficulty in obtaining the necessary authorizations for flying over the different territories.
27 balloons where launched from 5 September to 25 October, the last of which was destroyed on 1 February. They flew an average of 63 days and collected 150,000 observations.
4. Observing the ionosphere
The polar regions - and, for our country, the Antarctic bases - are important locations for observing the connections between the Earth and the sun, in particular the ionosphere.
The ionosphere is located at an altitude of over 90 km and forms a charged zone under the effect of the sun. It has significant meteorological and technological effects: magnetic storms can provoke gigantic power failures, especially in North America where the magnetic pole is located within Canada.
Aurora borealis and australis are undoubtedly its most beautiful manifestation. They are best observed at the geographical poles, because they are closer to the magnetic poles which concentrate the ionized particles emitted by the sun.
To measure these phenomena, SUPERDARN radars are used. They are the subject of an international cooperation programme to cover the North and South Poles.
In the southern hemisphere, France already uses one radar in the Kerguelen Islands. At Concordia, two trans-horizon HF radars will be installed for the longitudinal sectors between the Kerguelen and Tasmania and between New Zealand and the British Halley Bay base. They will function in pairs, one with a radar from the South Pole base and the other with the Chinese Zongshan base. They will be built and used within the framework of the programme of Franco-Italian cooperation at Concordia.
The international Superdarn network in Antarctica
( Source: IPSL-CNRS-UVSQ-Research Centre for Terrestrial and Planetary Environments)
The scientific objectives of the programmes for making optical measurements in the visible of the aurora australis at Dome C (Auroral Light Fine Analysis - ALFA) are:
- studying the energy and material exchange in the transpolar arcs;
- fine analysis of light emissions in the ionosphere (between 150 and 300 km in altitude);
- the interaction between high-energy electrons and the ionosphere;
- the formation of density irregularities in the regions of electron precipitation;
- the movements of plasma linked to the electrical currents aligned with the magnetic field.
B. ANTARCTIC ASTRONOMY: A NEW FIELD
Since July 2006, SCAR has recognized astronomic research as an important field of research in Antarctica. This research is in full expansion, of which the United States is already well aware as can be seen at their South Pole base, while France and Italy have a major asset in the form of the Concordia station.
1. Recognizing this fast-growing discipline
Reflections on the development of astronomy in the Antarctic began in the early 1990s and the first series of tests at the South Pole base took place between 1993 and 1994.
Ever since then, major projects have been developed at the American base.
Your rapporteur will here discuss two which seem to him to be particularly significant for the scientific influence: studying cosmic background and detecting neutrinos.
· Studying the universe's cosmic background
Measuring the universe's fossil radiation is a fundamental scientific and philosophical area of research, because it seeks to understand the state of the primordial universe and to get as close as possible to the moment of its birth, the Big Bang.
The first measurements were made by NASA's COBE satellite in 1992. This discovery allowed the American researchers John Mather and George Smoot to obtain the Nobel Prize in 2006 . They carried out the first precise observations of the cosmic background, the luminous radiation that appeared 300,000 years after the Big Bang. Fossil radiation had been accidentally discovered in 1964 by Arno Penzias and Robert Wilson at the Bell Laboratory. But at the time, it was impossible to measure this radiation from the Earth; this led to the COBE satellite project. For the authors, the main results of these observations were the confirmation of the Big Bang Theory (an expanding universe from an initial starting point) and the publication of a map of the cosmic background radiation revealing the temperature variations (anisotropies). These results would allow scientists to understand why the universe is not homogeneous, but rather made up of vacuums and islands of matter.
More recently, the measurements made by the WMAP (Wilkinson Microwave Anistropy Probe) satellite have been very largely disseminated. This satellite provides a new image of the early universe, one that is infinitely more precise than that provided by COBE. It shows a polarization and orientation of light. It allows scientists to specify the universe's distribution of matter: 4% of ordinary matter, 22% of dark matter and 74% of black energy. It allows scientists to clarify the formation scenario for the first stars and galaxies.
The Antarctic appears extremely complementary to research carried out in space. Indeed, the Antarctic's very specific conditions allow for work to be carried out of a precision equivalent to that undertaken in outer space. It also offers the advantage of allowing researchers to use the latest, most advanced equipment that can also be rapidly repaired.
Several experiments were carried out from the South Pole base, particularly in 2000 (Boomerang), from a measurement balloon.
In addition, within the framework of a collaborative programme between the United Kingdom and the United States, the QUEST (Q and U Extra-Galactic Survey Telescope) was deployed in 2004-2005 on DASI, an interferometer for measuring anisotropies of temperature and polarization.
In this field, on Concordia, within the framework of Brain, a Franco-Italian team installed bolometers. These sensors consist of a crystal whose temperature varies according to the energy of the particles that hit it. They are placed within a cryostat which cools them to a temperature close to absolute zero. 21 ( * )
At the time, these experiments allowed scientists to produce images of the cosmic background much more rapidly, much less expensively, and - taking into account the use of the most advanced technological equipment - much more precise than had been the case with the COBE satellite during its several years of use.
Today, this research is carried out on-site, so as to continue to clarify the measurements, under the personal direction of one of the two Nobel Prize winners, in preparation for the launch of the European Planck mission in 2008. What's more, the satellite's technology was tested in the Arctic from a balloon (the Archeops Mission) launched from Kiruna, Sweden.
· Searching for neutrinos: the Ice Cube Project
Another example of the importance of astronomical research carried out in the Antarctic is the international programme for the detection of neutrinos.
Under the direction of the United States and on the initiative of the University of Wisconsin at Madison (Prof. Francis Halzen), a very important research programme is underway on neutrinos. It receives $295 million in funding from the National Science Foundation (NSF), in association with several countries: Sweden, Belgium, Germany, the United Kingdom and the Netherlands.
This construction for this programme, known as Ice Cube , should be completed in 2009.
Neutrinos are elementary particles with almost no mass created by nuclear reactions. The sun and other astronomical phenomena produce low-energy neutrinos, while cosmic cataclysms such as black holes, supernova or the Big Bang produce high-energy neutrinos. Scientists are searching for the latter.
Once generated by these cataclysms, the neutrinos move at the speed of light and do not stop. Having virtually no mass, they very rarely interact with other particles, allowing them to move in a straight line all the way to the outer limits of the universe, passing through any celestial bodies - stars, planets and magnetic fields - on their path, as though they didn't even exist. In this manner, trillions of neutrons pass through Earth every nanosecond. However, for astrophysicists, each of these particles is a potential messenger carrying information on its origin.
However, neutrinos are extremely difficult to detect. They can only be detected when they collide with a molecule. The collision disintegrates the nucleus and the neutrino is transformed into another particle called a muon. The muon continues on the same trajectory as the neutrino, but can be detected thanks to the cone of blue light it creates (Cherenkov radiation), similar to the airwave produced by a bullet.
In order to successfully detect muons, one must observe a vast amount of a perfectly transparent substance in total darkness.
In the early 1980s, the United States attempted to create a detector off the coast of Hawaii in the depths of the ocean. However, the instable weather and sea conditions prevented this experiment from being a total success. Antarctica's ice would appear to be much more promising. A first generation already exists: the AMANDA (Antarctic Muon and Neurtino Detector Array).
The new generation is represented by the Ice Cube , which will consist of 5,000 photomultiplier detectors set in 1 km 3 of ice, at a depth of between 1,400 and 2,400 metres below the South Pole . It will therefore be possible to take advantage of Antarctica's darkness and crystal-clear ice. These detectors will serve to multiply the signal some 100 million times and to send it to the surface, where it will be processed by computer. In this manner, it will be possible to determine the particles' direction and origin, and therefore to study the cosmic event that created them.
This experiment is linked to other programmes abroad: Auger in Argentina, Antares off of Toulon, and Nemo and Nestor in southern Italy.
These research programmes carried out in Antarctica are also linked to one of today's most advanced domains in fundamental physics.
What's more, Raymond Davis was awarded the Nobel Prize in physics in 2002 for his research on neutrinos. He was one of the first, in 1968, to construct a basin filled with 600 tons of chlorine-rich solvent which was then buried 2,300 m below ground in the Homestake mine in the United States in order to detect neutrinos emitted by the sun.
Not finding all the neutrinos that he expected to find, he put forward the hypothesis of their oscillation; these results were confirmed in 1998 by the Japanese "Super Kamikande" experiment, which used a much larger detector. 22 ( * )
Neutrino research is not only derived from particle physics; certain researchers speculate that following the Big Bang, a background of neutrinos was present alongside the cosmic background already detected. 23 ( * )
2. Concordia: the best site in the world for astronomic observations?
For the Concordia station, two questions arise: Is the site as good as is hoped? What are the development projects for astronomy?
· Qualifying the site
Concordia Dome appears to be one of the best locations in the world for astronomy.
The Franco-Italian site would seem to combine all the ideal conditions for an astronomical observatory: clear, cold, dry, clean, dark, low precipitation, little wind, little turbulence, little seismic activity, accessible, climatic stability and the possibility of carrying out continuous measurements.
The atmosphere is very stable due to an altitude of 3,300 m, far from any pollution.
The little wind there is - less than 2.5 m/sec - blows in a constant direction. Its results are clearly superior to those of the great Chilean sites. This also represents a major difference when compared to the South Pole site, which is subject to katabatic winds due to an altitude of only 2,830 m, while Concordia is located at the summit of a dome.
A temperature of always less than -30°C should allow for increased performance in the use of infrared.
During the austral summer, image stability is less than 0.5 arc-seconds for 4 hours, or two times better than the best known terrestrial site, Cerro Paranal in Chile, where the European VLT is located. The scintillation is very low, offering a coronal sky.
During the austral winter - in other words, at night - the sky is clear 95% of the time.
However, between 0 and 30 m, the site is not as good and prevents any work from being carried out. These disturbances (0-150 m) are caused by the temperature inversion layer, with maximum disturbance between 0 and 30 m.
These turbulences must be made clear, in particular to determine if they are stable throughout the year in terms of altitude and thickness. If this is the case, they would not constitute a major handicap.
Indeed, the large instruments are built above this turbulence.
Therefore, the question is knowing if these supposedly excellent conditions do indeed exist and could lead to the installation of one, or even several, large instruments. We should have the answer to this question very soon.
· Defining a strategy for astronomy at Concordia
The prefiguration of European astronomy in the Antarctic is the object of a European network: ARENA (Antarctic Research, a European Network for Astrophysics). It is coordintated by Nicolas Epchtein, at LUAN (the University Laboratory of Astrophysics at Nice).
This network, registered at the 6 th PCRD, enjoys a budget of €1.3 million over 36 months between 2006 and 2008. France receives 36% and Italy 31%. This network is largely open, because, in addition to the two leader countries at Concordia, the following countries are also present: Germany, Spain, Belgium, Portugal, the United Kingdom and Australia, gathering together 15 laboratories and 120 scientists. Japan and New Zealand also sent representatives to the first annual conference in Roscoff.
Numerous projects are emerging from this reflection. They should be classified by priority, but demonstrate the scientific community's very great interest in this site: wide-range imaging, high angular resolution, precise photometry, interferometry, etc.
For your rapporteur, it is clear that looking beyond this question of the site's qualification, a credible strategy needs to be formulated for strengthening Concordia scientifically and logistically, by taking into account all the engineering constraints (energy, communications, transport, robotics, environment).
Therefore, we must first turn towards projects of a high scientific level but that are compatible with the current logistics, so as to then develop larger projects that could, in 10 to 15 years time, rival the Andean sites .
This strategy must also take into full account the desire of the Chinese to set themselves up on Dome A in a permanent manner, starting during the IPY of 2007-2008. Inspired by the Franco-Italian dynamics at Concordia, China would like to not only carry out very deep ice coring, but also develop an astronomical station taking advantage of the site's higher altitude (4,083 m) and enjoying similar, if not better, conditions than those of Dome C.
Today, there isn't cause to dramatize competition from China, but it should be taken very seriously. Indeed, last year, expedition to Dome A encountered a serious incident necessitating emergency assistance on the part of the Americans and the evacuation of one of the expedition's members. In addition, Dome A is undoubtedly one of the least accessible sites on the planet and significant, dependable logistics need to be put in place before a permanent station can be built in which researchers could winter. Several years of observation are also needed to validate the site's astronomical quality and start research.
Having said that, in the opinion of your rapporteur, competition from China engenders five proposals:
- The Concordia station must first and foremost demonstrate its scientific potential in astronomy.
- In particular, a consideration must be made of the its scientific contribution compared with that of the South Pole base , at which considerable material means are already available.
- It must then demonstrate a growing logistical capacity , perhaps by considering new routes.
- Europe must also define a political strategy to position its research at the highest international level.
- There is a limited amount of time to deal with all of these points.
· The scientific projects at Concordia
The scientific projects are gathered together within the Stella Antarctica project. IPY-certified, it is coordinated by Eric Fossat at LUAN. It distinguishes two important scientific subjects : the exoplanets and the early moments of the universe.
The first exoplanet was discovered less than 10 years ago. Since then, more than 100 planetary systems have been discovered. But no exoplanet, nor any planetary system similar to our own, has been directly observed. These planets are small, cold, dark and close to their suns. The observation instrument must therefore be specific and extremely precise. This research requires great angular resolution in the infrared. This would suggest using a network of Earth-based interferometric telescopes.
Following qualification, this project would be developed in two stages: an initial project of limited size to validate the project's potential and study via spectroscopy the nature and composition of the atmospheres of the already known exoplanets, allowing for the exploration of the disks of dust and gas in which the planets are formed. A much larger project could then be set up to make an inventory of the exoplanets.
The second big research subject is the polarization of the Big Bang's fossil electromagnetic radiation . It has a very weak component (type B modes) that corresponds to the imprint left by the gravity waves. It is very difficult to measure, because of its weak intensity and the large angular size of what is looked for in the sky. It necessitates a very stable microwave sky background, as is the case at Dome C.
The closest projects are the ASTEP (Antarctic Search for Transiting Extrasolar Planets) instrument, to be installed at Concordia in 2008. This 40-cm-in-diameter instrument will be used to detect exoplanets. This qualification instrument could be followed in 2012 by a larger one: Ice-T, coordinated by Germany.
In 2008, an Italian infrared telescope will also be installed: the International Robotic Antarctic Infrared Telescope (IRAIT).
As regards stellar seismology, France would like to carry out the SIAMOIS (Seismic Interferometer Aiming to Measure Oscillations in the Interior of Stars) experiment. This should allow scientists to understand the internal structure of stars, via a longterm and very precise photometric observation and in coordination with the Corot satellite. These conditions are to be found at Concordia, because the sky can be observed 90% of the time during several consecutive months. SIAMOIS will pay particular attention to shining stars of little mass detected by Corot. The programme should be carried out over 6 winters starting in 2010, for a cost of €860,000.
In addition, in preparation for the Darwin space mission to discover exoplanets and search for life, French researchers are planning an Alladin mission, based on the principle of black-fringe interferometry. Its objective would be to demonstrate on Earth Darwin's expected technical functioning and to validate the scientific concepts. It will contain two telescopes within a tool 40 m in diameter, simulating the formation flight in space of the Darwin mission satellites.
Scientists imagine for the future a gigantic infrared interferometer consisting of 36 telescopes covering an area of 1 km 2 , the cost of which would be similar to the large Andean instruments.
3. Searching for meteorites in Antarctica
Although the first meteorite was discovered in 1912, it was not until 1969, following the simultaneous discovery of four meteorites, that Antarctica was recognized as being a formidable hunting ground. Indeed, meteorites statistically imprisoned in the ice 24 ( * ) are progressively concentrated by the large glaciers and later resurface in certain areas, in particular when terrain features push up the ice.
Two thirds of all meteorites were discovered in Antarctica!
At Concordia, it's not only a question of collecting as many as possible, but, on the contrary, of discovering new types of meteorites. Indeed, the Concordia site is subject to very little horizontal movement, which is why it was chosen for ice coring.
This characteristic, already taken advantage of for ice core dating, is also a great asset for measuring the abundance of meteorites and their composition over time on our planet; it could also allow for the discovery of variations.
The Concordia site also provides scientists with access to meteorites that were only a little transformed during their fall through the atmosphere, due to the atmospheric particularities at the poles.
The programme carried out in the summer of 2006 was a great success, with 1,500 particles 20-50 micrometres in diameter having been collected.
Finally, the purity of this exceptionally well preserved site allows scientists to locate very small meteorites - submillimetric and micrometric - because the collection area is made up entirely of snow. These meteorites are also exceptionally well preserved considering the amount of time spent on Earth, because they are not contaminated by other dust particles, thanks to Concordia's great distance from any dust-carrying currents. The French research team, directed by Jean Duprat, hopes to be able to demonstrate the existence of cometary micro-meteorites or meteorites from the external solar system. They should provide information on the conditions of planetary formation, 4.5 billion years ago.
4. Measuring cosmic radiation
France has installed neutron monitors in the Kerguelen Islands since 1964 and in Adélie Land since 1968 , with a break in the latter location from 1977 to 1982. These monitors measure high-energy particles emitted by the sun and other stars. These observatories are part of an international network (the International Space Environment Service - ISES).
(Source: the Paris-Meudon Observatory - LESIA)
At the national level, the objective would be to make them an ORE to stabilize the research activity.
Instruments placed at the French bases are used to count the particles, allowing scientists to monitor their source and energy.
The primary particles of cosmic radiation (85% of protons) do not reach the ground. Their collisions with atmospheric particles create secondary particles - nucleonic components consisting of protons and neutrons. They can be detected on the ground if the kinetic energy of the original particles is over 0.5 GeV.
Before reaching the atmosphere, cosmic rays are deflected by the Earth's magnetic field, which forms a "geomagnetic break" limiting a particle's capacity to reach the ground. The least-energized particles only reach the surface in the high latitudes.
Each station is also characterized by an "asymptotic direction", or the deviation of the particle - according to its energy - in arriving vertically at the station. For example, the low-energy particles that arrive vertically in the Kerguelen Islands come from areas of the celestial sphere located above Brazil. Their propagation is so complex that two nearby stations such as McMurdo and Dumont d'Urville have opposite asymptotic directions.
These neutron monitors provide valuable information on solar activity, because cosmic radiation depends greatly upon solar activity. Strong solar activity provokes a reduction in cosmic radiation, due to a phenomenon of repulsion provoked by the heliospheric magnetic field (a timescale of one year), a temporary reduction due to particle ejections (a timescale of one day) and, finally, by the production of certain relativistic particles during certain irruptions (a timescale of a few minutes). 25 ( * )
These magnetic observations are applied directly to human health, because exposure to natural radiation is now monitored, in particular the exposure of the airlines' flight personnel . This monitoring is organized by European directive no. 96-29 EURATOM of 13 May 1996 on exposure to ionizing radiation.
In France, this data is stored in the SIEVERT (Computerized System for the Evaluation During Flight of Exposure to Cosmic Radiation among the Airlines) system. This service, established by the DGAC (Department of Civil Aviation) for professionals, is also made available to the general public as an informative measure and teaching tool. The most exposed air routes are those passing over the Far North - in other words, flights to North America or Asia from Europe. The occupants of the polar bases are also exposed.
In the future, measuring radiation will also be important to protect planes from experiencing power failures .
In a more fundamental manner, understanding variations in solar radiation and measuring the isotope 10 of beryllium ( 10 Be) in the ice cores should allow for progress to be made in the reconstruction of past solar activity.
Thus, Antarctica is proving to be an exceptional zone for scientific observation. This leads your rapporteur to make the following three conclusions:
- It is desirable to support and perpetuate the observation activities at our bases , because they are essential for understanding our planet. Wasn't the hole in the ozone layer discovered by accident thanks to routine stratospheric measurements? What's more, these activities only make sense if they are permanent, without interruption and carried out at an international scientific level allowing for their integration into the computerized networks.
- Our country must fully participate in the scientific research being carried out on stratospheric ozone in the polar regions, because the success of the Montreal Protocol, which will celebrate its 20 th anniversary during the IPY, makes it a model for the shared handling of global problems.
This is symbolized by its objective of returning emissions to their natural levels. It should serve as inspiration in our handling of climate change.
- Finally, France and Italy must become fully aware of the exceptional qualities of the Concordia site for astronomy and develop a two-phase strategy for strengthening their position: programmes targeting scientific excellence but requiring little in the way of logistics, followed by a positioning of the station to welcome large European instruments with the necessary logistics in 10 to 15 years time, while taking into account the opportunities already offered by the South Pole base and possible competition from the Dome A site.
* 18 The geoid is a more precise representation of the Earth's surface than the spherical or elliptical approximations. As an equipotential surface with a specific weight, the geoid serves as a reference point for precise measurements.
* 19 The problem with stratospheric ozone is not connected in any way with the ozone-peak phenomena observed in heavily polluted, urban areas. The ozone located at ground level is not connected to that located in the stratosphere. This is best understood by taking into account the different layers of the atmosphere:
- the troposphere: 0-12 km in altitude.
- the stratosphere: 12-45 km in altitude
- the mesosphere: 45-90 km in altitude.
- the ionosphere: over 90 km in altitude.
* 20 Chlorofluorocarbon.
* 21 Absolute zero: 0 kelvin (K) = -273.16°C.
* 22 Jean Orloff, Université Blaise-Pascal Clermont-Ferrand, La Recherche, No. 402, November 2006.
* 23 Julien Lesgourges (CNRS), La Recherche, November 2006, No. 402.
* 24 Every year, 5 to 6 thousand tons of meteorites fall on Earth.
* 25 Your rapporteur is here referring to an article by Pierre Lantos and Christophe Marqué (CNRS, the Paris-Meudon Observatory, Laboratory of Solar and Heliospheric Physics) and a presentation by Karl Ludwig Klein of LESIA.