The year 2001 marks a turning point for the Atmospheric and Space Physics (ASP) program. For the first time for many years (since 1957 for Mawson, early 1980s for Macquarie Island) there are no people wintering at Mawson or Macquarie Island whose primary role is to support atmospheric and cosmic ray physics research.
Despite this, the ASP program is alive and well at both stations, as well as Casey, which will go automatic from 2002. Autonomous equipment will enable continued logging of essential data under the control of ASP personnel at Australian Antarctic Division headquarters in Kingston, Tasmania. Standard riometer and magnetic pulsation observations will continue at all three stations, as well as fluxgate magnetometer observations at Casey, all-sky imaging at Casey and Macquarie Island, and cosmic ray observations at Mawson.
The automation program, which implements a recommendation of Australia’s Antarctic Program Beyond 2000 (1997), puts ASP at the leading edge of instrument automation. The program was aimed at continuing collection of essential data from each station while reducing operational costs to allow resources to be diverted to major programs at Davis, including the LIDAR project.
Three new systems have been developed to control and collect data from these experiments.
An analogue data acquisition system (ADAS), designed to collect time-stamped, time series data from any analogue signal is currently used to log data from the riometer, magnetic pulsations and fluxgate magnetometers. Data collection is synchronised to a GPS (global positioning system) chronometer allowing data to be sampled with a time resolution of one millisecond, allowing accurate propagation delays to be estimated from data recorded at multiple sites.
The all-sky imaging system (ASIS), a specialised data acquisition and control system designed to record the night time activity in the skies over each station, uses a monochrome video camera fitted with a fish eye lens to take a circular horizon to horizon image of the sky every 30 seconds. These images are annotated with the time and date and then stored in digital format on hard disk for later transmission back over the satellite link.
Logging of data from the Mawson Cosmic ray observatory is now fully automatic, thanks to enhancement of an earlier automatic system that required weekly visits for essential manual intervention. The current system collects data from the neutron monitor and three surface muon telescopes and from the four underground muon telescopes (using the rock to filter out weaker cosmic radiation) on a one minute sampling basis. Also collected are outside and inside air pressure, laboratory and vault temperatures, and wind speed.
The new ADAS system was installed at Casey, Macquarie Island and Mawson in 2000–2001, while ASIS systems were deployed at Casey and Macquarie Island and the updated COSLOG system was commissioned at Mawson.
Data distribution
A major ASP observatory task is ensuring that data gets to the researchers needing it. These experiments provide valuable background data for advanced research elsewhere in the world. To reduce the data collection and archiving workload, arrangements have been made with IPS Radio and Space Services in Sydney, which has recently become a World Data Centre and also performs ionospheric forecasting. Every five minutes data is sent from each station to IPS in Sydney and then fed into forecasting models, and 24-hour files are sent to IPS for long term archiving. The Australian Geological Survey Organisation (AGSO) receives daily copies of the magnetic data from Casey.
Cosmic ray data are transmitted back to Kingston each day and even the large all-sky imaging files can be squeezed back over the satellite link during off peak times.
The permanent satellite data links between Kingston and the stations provide limited bandwidth. New software allows scheduling of large data transfers at off peak times to make efficient use of the link. While some data files are required at up to three different destinations, care is taken to avoid multiple transfers of the same data over the ANARESAT link. Copies of transferred files are made at Kingston and sent to interested agencies.
So who fixes the equipment when it breaks down? And how do we monitor data quality remotely?
Remote power switches at each station are a first line of defence, providing mains power to ASP experiments and allowing individual items of equipment to be switched on and off under commands transmitted via satellite. Kingston staff can thus reset any recalcitrant equipment and switch off sensitive optical equipment over summer to save on power and protect the equipment.
Of course, unattended observatories raise the risk of reduced data quality with no specialist skills on site to monitor data as it is being collected and repair problems as they occur. The ASP program still relies on people at each station making regular equipment inspections. The all-sky imager dome still needs to be cleaned and station lights monitored. Physical equipment failures can still only be resolved with the human touch, although as older equipment is gradually upgraded even this requirement will be minimal.
All new automatic systems use email to keep in touch with Kingston headquarters. Any error conditions are stored in log files which are sent to Kingston to enable problems to be detected and rectified as soon as possible.
Future developments
The ANARE physics community has been encouraged to automate future experiments before deployment at stations, and to locate experiments at Davis where this is consistent with scientific objectives.
The DPS-4 Ionosonde will be moved from Casey to Davis in 2001–2002 so that it can be supported by wintering expeditioners. The GPS chronometers at Casey, Mawson and Davis will be upgraded to ensure accurate and dependable timing. An all-sky imager system will be reinstalled at Mawson after some renovation work, and ADAS and ASIS systems will be deployed at Davis, enabling expeditioners to concentrate on major research work.
Monitoring of ASP instruments and their environment will be done using webcams (such as checking build-up of grime inside the all-sky imager domes) and the Australian Antarctic Division’s building monitoring and control system.
Mechanical switches and knobs on future ASP equipment will be replaced with digital controls that can be activated and adjusted remotely. New systems will be designed specifically for autonomous operation.
Lloyd Symons1, Ray Morris2 and Marc Duldig2
1. Science Technical Support, Australian Antarctic Division
2. Atmospheric and Space Physics Program, Australian Antarctic Division