SANAE - Research

	Research Projects
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	SANAE's research is divided into four programmes: Physical sciences Earth sciences Life sciences Oceanographic sciences Only the physical sciences programme is conducted year-round at SANAE IV. The other programmes are conducted during the short summer period when the temperatures and weather permits field work and the extent of the sea ice is at its minimum. The Southern Hemisphere Auroral Radar Experiment (SHARE) Antarctic Magnetosphere, Ionosphere Ground-based Observations (AMIGO) Antarctic Research on Cosmic Rays (ANOKS) Astrid satellite telemetry station Upper Atmosphere Physics GPS Project
	The Southern Hemisphere Auroral Radar Experiment (SHARE) SHARE is a high frequency coherent phased array radar experiment. The SANAE array is operated in conjunction with the similar systems at the British Antarctic Survey's Halley Station and the Japanese Antarctic Research Expedition's Syowa Station, each approximately 1000 km from SANAE. Data from the radars are combined to provide information about electric fields, velocities and irregularities in the upper atmosphere over a large region of Antarctica. SHARE is an international collaboration involving the University of Natal, Potchefstroom University, The British Antarctic Survey and John Hopkins University Applied Physics Laboratory. SHARE is part of the world-wide Super Dual Auroral Radar Network (SuperDARN).
	Antarctic Magnetosphere, Ionosphere Ground-based Observations (AMIGO) The magnetosphere has a significant effect on the earth’s environment. It protects the earth, deflecting the flow of the solar wind around it and shielding life forms from potentially dangerous levels of radiation. Changes in the solar wind can trigger magnetospheric processes which have been known to disrupt radio communications, cause damage to satellites, disrupt or destroy large networks of electric power lines and on occasion threaten astronauts and Concorde passengers with harmful levels of proton fluxes. It is in this hostile environment that crucial communication and navigation satellites operate. An interest in magnetospheric research is driven by a desire to understand this region that is so important for our environment and industry as well as by the fact that it presents us with a readily available astrophysical plasma laboratory where we can observe plasma processes known to occur elsewhere in the universe which are difficult, if not impossible, to recreate in terrestrial laboratories. The advent of satellites has added much to our knowledge of the magnetosphere. Since the 1957 International Geophysical Year, researchers have gained a morphological description of the magnetosphere, the plasma populations within it, and its interaction with the solar wind. An understanding of the physical processes within the magnetosphere is however still inadequate. Regions of the magnetosphere project along field lines onto the ionosphere so that at medium and high latitudes the upper atmosphere may be regarded as a viewing screen for processes occurring in the magnetosphere. Many of these processes produce emissions in the visible and radio parts of the electromagnetic spectrum and measurements of these emissions provide information about the processes. Hence the polar regions provide an excellent base for studying magnetospheric phenomena. The advantage of Antarctica over the northern polar regions is that it provides a fixed land mass from which to conduct observations. Numerous stations, both staffed and automated observatories, have been set up by various nations in Antarctica for the purposes of studying the magnetosphere. A number of theses are located at the footprints of different magnetospheric regions, allowing a better analysis of these regions. The Japanese Syowa station for example lies beneath the auroral oval, placing it in an ideal location for observing auroral displays. The South African SANAE base as well as the British and American, Halley and Siple bases lie beneath the mean position of the plasmapause, an important field-aligned surface, marking the boundary between the relatively cool plasma of ionospheric origin and the hotter plasma emanating from the solar wind. At about 60° magnetic latitude, SANAE IV is well situated not only because of its proximity to the plasmapause, but also because during periods of high geomagnetic activity it falls beneath the auroral oval, making it ideal for optical studies of the aurora. It is also close to the boundary between open and closed magnetic fields. It is near the South Atlantic magnetic anomaly, which is of intrinsic interest as an energy sink and has been extensively studied by South African scientists. It is well situated to make radio studies of the magnetosphere because of the low levels of ambient man-made noise. Since the 1960’s this region of the earth’s environment has been studied by making both ground and satellite observations, and through collaborative studies with numerous other research groups. AMIGO is a collaborative programme between the University of Natal, Durban's Space Physics Research Institute and Potchefstroom University's Space Research Unit. It contributes to the international co-operative programme STEP (Solar-Terrestrial Energy Programme). AMIGO’s objectives are to investigate energy transfer processes in the magnetosphere and ionosphere, especially those associated with sub-storms, VLF-particle interactions, radio propagation, hydro-magnetic waves, ionospheric irregularities and disturbances. This is achieved by carrying out a programme of ground-based observations of wave and particle phenomena in the magnetosphere-ionosphere system using the following: 3-component magnetometers, including instruments with sensitivity (a few nanotesla) for recording main field components and for studying ULF pulsations (around 1 Hz). The Pulsation Magnetometer measures rapid (<1Hz) fluctuations in the X and Y components of the earth’s magnetic field. Data are displayed on a monitor in real time and also stored digitally. The display also gives the Fourier transform of the data in 210 second intervals. The data are used in conjunction with VLF data, quasi-periodic VLF emissions being associated with magnetic pulsations. The instruments are important also for auroral and riometer observations. Imaging Riometer for Ionospheric Studies (IRIS) The IRIS antenna is a 64-element matrix arranged in an 8x8 pattern. Each of the elements is a circularly polarised crossed dipole (turnstile), ¼ wavelength above a ground plane with a ½ wavelength spacing between each element. The operating frequency is 38.2 MHz. Sixty-four independent beams (13 degree width) cover an area of 200 x 200 km at an altitude of 90 km above the Earth. Electron precipitations, resulting from solar activity, in the ionospheric D and E layers are investigated by examining the absorption of cosmic radio noise from stars in the Milky Way. Dynamic events can be examined by making correlations between signals originating from different directions and detected by the riometer that measures ionospheric absorption of galactic radio noise. View photograph of the riometer. Auroral imaging devices are low light level video cameras for studying the motion of auroral forms. The Auroral All Sky Camera is particularly used in conjunction with the Swedish Astrid 2 satellite electric field measurements. The objective is to establish what electrical field structures are related to particular auroral forms. We also look for correlations with absorption events measured by the 64-element array riometer. The 30^o Camera is a narrow field of view camera used to get better resolution of structure in auroral forms. During aurorae the all-sky CCD camera is operated and video images are continuously recorded. The camera output is displayed on a monitor next to the 30^ocamera which can be pointed at interesting features to give better resolution. Output from this camera is also continuously recorded. The real time SHARE display is used to forecast auroral activity. On this the expansion of the auroral oval can be seen. The extent of the expansion gives an indication of whether or not the aurora will come within range of our cameras. The magnetometer real time display can also be used as a predictor of auroral activity. Future Plans: To use filters on the cameras to study auroral lines and "forbidden" atomic transitions not yet observed in terrestrial laboratories. VLF direction finding system is used to record whistlers and other VLF emissions. The data is recorded on video tapes normally on a 1 minute in 5 basis. Spectrograms of the incoming signal are displayed on a monitor in real time allowing the operator to switch to continuous recording during periods of high activity. Periodic VLF emissions are often associated with magnetic pulsations. These data are used in collaboration with similar recordings made by the British Antarctic Survey at Halley to determine magnetospheric electric fields. Omnipal Receivers measure phase and amplitude changes in signals from 6 VLF transmitters situated in Europe, the USA and Australia. This is an effective way of studying wave induced electron precipitation into the atmosphere. The most common signature is the Trimpi. The signatures due to auroral precipitation have yet to be established. The data are recorded continuously and studied in conjunction with the VLF wave experiment. The data are also displayed on a monitor in real time. Top
	Antarctic Research on Cosmic Rays (ANOKS) To investigate transport and acceleration of solar and galactic cosmic ray charged particles in the heliosphere from neutron monitor recordings and to integrate these recordings with data obtained by neutron monitoring ground based stations at other locations and by satellite or spacecraft observations. To pass on hourly neutron monitor count rate data to World Data Centres that do long-term investigations and small count rate data from studies of ground solar level events. Top
	Astrid satellite telemetry station SANAE runs the Southern Hemisphere’s telemetry for Swedish satellite Astrid 2. The tracker can also be used in a joint Swedish/Danish/SA collaboration involving the Oersted satellite. SANAE is a partner in the Astrid 2 project and has access to all data downloaded and software from the satellite. In return SANAE provides simultaneous ground based aurora, magnetometer and VLF radio wave measurements. Top
	Upper Atmosphere Physics SAOZ measures total column ozone. Results showed the influence of the ozone ‘hole’ at SANAE. Provides the potential for studying trends in ozone depletion. YES measures UV fluxes in the wavelength 280-320 nm. There is a complex relationship between ozone depletion and UV fluxes. These measurements complement those of the SAOZ The dynamics of ozone depends on a stratospheric polar vortex which develops in the Austral Spring. We seek to gain insight into this by the use of an identical SAOZ and YES equipment in Durban. These observations are also used to complement satellite measurements of ozone. Top
	GPS Project SANAE's GPS project is a common effort of the Chief Directorate Surveying and Land Information in Cape Town, South Africa and the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany. The receiver, a trimble 4000ssi with choke ring antenna, was installed in March 1997. The station has become part of the world wide network of IGS stations (International GPS Service for Geodynamics) and is also used for local geodetic surveys. The IGS is based on more than 140 globally distributed permanent tracking sites and provides: high quality orbits for all GPS satellites Earth rotation parameter contributions to the determination of the tracking site co-ordinates and their velocities daily RINEX files for each IGS site The GPS station at SANAE was a key station within the frame of the SCAR-GPS campaign in 1998. The objectives of this GPS campaign were: linking of Antarctica with the Global Terrestrial Reference Frame (ITRF) with highest accuracy confirmation of the relative rates and direction of the Antarctic Plate with respect to the adjoining plates and microplates determination of the relative motion of crustal segments within the Antarctic Plate unification of the vertical datum, determination of the height of the mean sea level at tide gauge stations determination of the vertical motion of the Antarctic lithosphere due to the changes of the ice and ocean loading. In addition, permanent fixed GPS monitoring sites can be used for estimation of tropospheric and ionospheric trends and effects. Top
	SAWS The South African Weather Service operates a meteorologacal office at SANAE IV to collect meteogological data for mostly research purposes.