History of Mawson Meteorological Office

Mawson Meteorological Office

Work on the construction of a permanent station at Mawson commenced in February 1954. Mr Bob Dingle was the Bureau of Meteorology weather observer among a wintering population of ten. Construction work that year needed all hands. Routinely, and on the several exploratory field trips, weather details were recorded daily off station, and three-hourly on the station. Surface observations include temperature, humidity, pressure, wind speed and direction, clouds and visibility. Pen-on-drum instruments gave a weekly trace of pressure, humidity and temperature.

By June of 1955 the building work had progressed to include a dedicated Meteorological office. Using a transmitter attached to a balloon, upper air observations could then be made to give a vertical profile for temperature, pressure and humidity to more than 20,000 metres. This radiosonde flight was done once a day. With a theodolite tracking the balloon, wind speed and direction could also be calculated to the same height. With staffing increased to three people, two additional daily wind-only balloon flights were done as well. During the late 1950s and early 1960s the surface measuring equipment at Mawson was increased to include recording of solar radiation data, and the Dines anemometer gave a daily chart trace of the wind speed and direction. The installation of a tracking radar in 1967 greatly enhanced the wind data previously available when only a theodolite was used. Being a visual instrument, the theodolite was limited by cloud height and the range of the balloon. Wind data could now be recorded to 25,000 metres. Routine upper air observations have included as many as two radiosonde flights and two wind-only flights daily. With no more than four Met. staff, and using manual instruments and equipment, this was a tremendous effort, even in good weather.

The Fielden remote recording temperature instrument was introduced in 1973 and a Vaisala humidity recorder in 1980. By 1986 satellite pictures of the Mawson area could be downloaded at the station, providing useful information about clouds, pressure systems and sea ice distribution. In 1989 the manual calculations for the radiosonde data were replaced with a computer program. In 1990, the Digicora was introduced, performing a complete, combined upper air radiosonde and wind observation. The radar, a high maintenance instrument, was no longer needed. The radiosondes incorporated an aerial which accessed the Omega system (developed by the U.S Navy) to track the transmitter on the balloon and give wind data. This gave greater discrimination than was possible with the radar or the radiosonde receiver, with 5 second data now available. In 1993 a new building included an electrolyser for generating the hydrogen gas used in the balloon. This improved work safety and was a cleaner means of producing the gas than the old method of chemical generation with manual mixing and a resulting caustic residue. A small number of commercial hydrogen cylinders are always held on station to cover emergency needs. At this time fully automatic weather station facilities were operating with remote reading instruments for temperature, humidity, pressure and wind speed and direction, and capable of recording one-second data. By the late 1990s the Omega system was no longer needed by the Navy and was discontinued as it was an obsolete technology. Radiosondes with a GPS aerial were introduced for wind data, and are currently still used.

Over the years Bureau observers and engineering technical officers have been included in numerous scientific field programs. Their job is to record ground conditions as part of the scientific program, and for helicopter and small plane movements associated with the field party's establishment and relocation.

Surface and upper air weather data is needed for aviation between stations in Antarctica, and between the stations and the ships that travel to Antarctica each summer. Air travel within, and to, Antarctica is increasing and will become the routine means of deploying people. Tourist ships have an increasing presence in Antarctic waters and they rely on forecasts generated using weather observations made at Mawson and other locations.

Construction work at the stations is significantly weather-dependent, and a visit to the Meteorology office is a routine start to the day for the building crews. Cargo operations for ships at the station are done in consultation with the Met. staff. Similarly, receiving all available information from the Met. Office is a standard requirement for extended travel off the station in winter. Davis station, 500 kilometres to the west, has meteorologists during summer to assist the air operations from Casey, Davis and Mwason which are needed to support science programs. For longer range flights between stations, surface and upper air data recorded at Mawson has a more immediate local application. Additionally, aviation requires closer monitoring of the weather and detailed half-hourly reports of conditions are recorded for the duration of the flight.

Air quality is of increasing concern, and careful monitoring is done at Mawson for Australian and international organisations and institutes. The Bureau staff undertake this sampling. The number of associated agencies varies over the years. At present we do air sampling every 10 days for the CSIRO Division of Atmospheric Research. The U.S Department of Energy also has a continuous sampling procedure which we monitor and from which we record and transfer data. In summer 2004-5 sampling equipment will be installed for the Australian Radiation Protection and Nuclear Safety Agency and this will be work will be done by the Bureau staff.

In 1998, increasing automation enabled the Australian Geological Science Organisation to reduce their manned presence at Mawson for their seismological studies. The remaining manual calibration and monitoring tasks were taken on by the Bureau of Meteorology at Mawson. One observer is formally interviewed and assessed for this work by AGSO, which also provides training.

Global warming is of increased interest and recent station history has produced an unexpected data base for climatology studies. Sea ice thickness is measured in autumn and spring when the ice is forming, and breaking up. This is necessary for determining safe travel over the ice for pedestrians, light vehicles, heavier motorised equipment, planes and helicopters. This 50 year history is valuable information and is now enhanced with routine weekly drilling and measurement at four standard reference locations near the station. Responsibility and supervision for this work is assumed by the Bureau staff, with the assistance of several volunteers.

Some work comes our way because our daily routine includes a very early 4:30am start when some visual phenomena are more likely to occur or be visible. The appearance of stratospheric and noctoluscent clouds indicate other physical processes occurring in the atmosphere. This is of interest to physicists at the Australian Antarctic Division in Hobart, and the upper air physics program at Davis station. At Mawson the Met staff routinely monitor the sky in the early hours and oversee this cloud log with the participation of enthusiastic sky watchers on the station.