Most people at the Australian Antarctic stations are employed by the Australian Antarctic Division but there are a select few who work for the Bureau of Meteorology. Eleven each year in fact. At Mawson the Met Team consists of two people, the Met Tech (electronics technician) Kelvin and the Senior Obs (technical officer observer / Officer in Charge), myself. The other stations have an additional observer and cover more observations.
The met tech works the observations roster, carries out the maintenance and repair of all the met equipment on station and writes the tech reports. The senior obs manages the observations side of the office, rosters, writes the met reports, and is a part of the station leadership team.
During the summer we provide aviation observations for pilots and forecasters as well as ship observations on the Aurora Australis. We also have extra scientific work throughout the year, like the clean air sampling done twice a month that allows the CSIRO to monitor carbon dioxide levels in the atmosphere and routine tasks for the Ionic Prediction Service (IPS).
The major observations covered each day include the synoptic surface observations and the upper air program. The data we collect is sent to Australia and shared around the world through the World Metrological Organisation (WMO). The data is used by meteorologists for real time forecasting, in forecasting models and becomes a part of the Australian Data Archive for Meteorology (ADAM) also known as the climate record.
A synoptic observation records air temperature, humidity, wind speed and direction, and surface pressure from the Automatic Weather Station (AWS) with the observers adding in the manual component of visibility, weather and cloud. Messages are coded and sent every three hours with maximum and minimum temperatures included in the 9am and 3pm observations. This is the information you’ll see on TV, the Bureau’s website or in the newspaper. There are 100 weather groups to choose from, with blowing snow being the most common at Mawson. The duty observer also has the privilege of deciding if it is officially a blizzard (also called a blizz day) or not.
The Mawson upper air program consists of one balloon flight a day. At 1115z (1615 local time) an 800g balloon is sent off with a radiosonde attached underneath. The sonde has sensors to record temperature, pressure, and humidity every two seconds. It uses GPS to calculate its position and movement and thus wind speed and direction. The data collected gives a vertical profile of the atmosphere to about 30km above the station or ideally to 5hpa. It’s primarily used for forecasting, models, climatologically and to calibrate satellites.
The Met Team works a roster, covering seven days a week, 365 days a year, with the only day off being midwinter’s day (it’s a leap year this year!). This means that no matter how bad the weather is outside, Met always gets the full Antarctic experience. Some days there is nowhere better to be working but on blizz days, with the wind howling, snow blowing and visibility down to a few metres. Trying to release the balloon is a challenge.
Once the balloon is inflated, the sonde is attached and then the fun begins. Often there is a pile of snow outside the balloon shed doors, requiring some shovel work before you can release the balloon. Blowing snow may even leak in through the door seals, piling up on the floor. With snow whizzing about, we carefully unhook the balloon and take it outside. The balloon buffets you as you carry it out the doors and on occasion you may even get dragged along before you release it, hoping it won’t be caught in a rotor. Rotors are caused by the wind gusting over and around the balloon shed, and have been known to roll a balloon along the ground, pull it back towards the balloon shed or suddenly push it into the ground destroying the sonde on impact.
In the six and a half months since we’ve been at Mawson we’ve had 15 blizz days, 40 days of blowing snow (visibility <1000m), 188 strong winds days (wind speed 22-33kts) and 123 gales (wind speed >34kts or 63km/h).
We can happily say that we’ve only missed one balloon flight this year due to adverse weather conditions, though we might have had a few second releases and even one third release in an attempt to get the balloon away.