Our offshore automatic weather stations in the Coral Sea
20 January 2015
In late January 2014, as tropical cyclone Dylan bore down on the Queensland coast, residents could monitor the path and progress of the season’s first Category 2 cyclone with up-to-the-minute data from one of the world’s most sophisticated networks of offshore weather stations.
As the newspapers rolled out headlines about ‘Cyclone Dylan blowin’ in the wind’, land and marine radio and the Bureau’s website kept thousands of people informed of the precise speed and direction of that wind—with data sourced directly from an array of high-tech weather stations across the Coral Sea.
From Bougainville Reef just north of Cairns to Cato Island 375 km east of Gladstone, we have 15 offshore automatic weather stations (AWSs) in the Coral Sea.
The Times They Are a-Changin’
We have been operating weather stations in the Coral Sea for nearly 100 years, since building a staffed monitoring station on Willis Island (450 km east of Cairns) in 1921. In 1966, we established the region’s first automatic station on Cato Island, quickly followed by a second at Marion Reef off Townsville.
In those early days, the hardy meteorologists stationed on Willis Island used Morse code to convey the day’s wind, temperature and air pressure readings to Brisbane—and fresh lead-acid batteries had to be delivered to the island every six months to power the station’s equipment.
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Today, the latest weather sensors and data are automatically updated every minute and relayed through high-speed, solar-powered satellite terminals. ‘There have been phenomenal improvements in solar technology in recent years, with robust panels and batteries that are cheap, easy and will last you ten years – as long as you look after them and they don’t get destroyed by a cyclone,’ says Phil Keough, who oversees maintenance of the AWS network from our Cairns office. The AWSs around the Great Barrier Reef naturally have to adhere to strict guidelines concerning their structure and proximity to the world’s most prized marine ecosystem. We have rigorous operating and maintenance protocols for areas of specific value or vulnerability. For example, some stations located in special bird-nesting or turtle-breeding sites can only be accessed at certain times of the year. |
An offshore weather station platform in the Great Barrier Reef |
Watching the birds
Each year, before the start of the cyclone season, the maintenance team heads out on the water to make sure that every AWS is running smoothly. This involves not just checking the electronics and the solar systems, but often also clearing large quantities of guano left by the seabirds that use the mounts and solar platforms as roosts.
‘The guano tends to build up, and if you add rain to the equation it can get very acidic and accelerate corrosion of the aluminium platforms,’ says Phil.
Fixing offshore Automatic Weather Stations
Fixing offshore AWSs is a complicated business that naturally takes much longer than maintaining their land-based counterparts. If a station is damaged by a cyclone, we firstly prioritise the safety of our staff, and then weigh up the significant costs of repairing the station against its specific data-gathering capabilities. Some of the more remote stations, like Frederick Reef and Lihou Lighthouse, can require five-day round trips to carry out repairs. Fortunately, the improved communications of most AWSs now make it much easier to correct faults and upgrade systems remotely—dramatically cutting maintenance bills.
The notoriously rough seas and variable weather of the Coral Sea do make for significant challenges, though. Boats must be hired and technicians trained for seagoing activities. We must wait for a break in the weather to ensure that our technicians can be landed safely on an AWS in open waters. Occasionally, the entire platform will need to be replaced. This involves months of planning, and months of careful construction work to complete.
It all comes with the territory of watching the weather (and the water) in one of the most cyclone-prone stretches of ocean in the world.
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