Credit: Cole Bennets
Tregoning works as a geophysicist at the Australian National University (ANU) in Canberra, specialising in geodesy, which is studying large scale changes on Earth.
He began his academic career with a Bachelor in Surveying at the University of New South Wales in Sydney, before moving into a PhD in geodesy. After a post-doctorate in the U.S., he found himself at ANU in 1995 and has been there since, studying the changes of the earth using satellites.
He said he never planned a life of academic, but always knew he wanted to work outdoors. The two happened to synchronise beautifully. “I love my job, I have one of the best jobs in the world,” he says. “I get paid to learn! The application of space geodesy to studying changes on Earth … has become more relevant to society of late since satellite missions are relied upon to quantify the effects of climate change," he adds.
Tregoning's research involves using GRACE (Gravity Recovery and Climate Experiment) GRACE to measure changes on the Earth. These include plate tectonic drifts, earthquakes and the movement of water. “This movement can tell us what happened thousands of years ago to the land,” he says. He can accurately measure the uplift of land and subsidence (the movement of land downwards) to a five-millimetre point. This movement, according to Tregoning, can tell us what happened thousands of years ago to the land.
GRACE is composed of two satellites roaming the earth at 450 km in the sky, approximately 200 km apart. By measuring the distance between the two satellites, Tregoning is able to tell what the gravity field of an area is. This is because the satellites are drawn towards certain areas and pushed away from others.
Tregoning explained that changes in mass on the surface of Earth could cause floods and droughts. He said we could tell if Antarctica is melting (as well as other land and water movements) by the changes in the gravity field around it based on the information GRACE feeds back to Earth.
NASA and the German Space Program launched GRACE in 2002 to survey the different gravity fields on earth and how they change. Gravity fields are constantly changing on earth, such as when the tide comes in at the beach or when a drought occurs. “My team at ANU has been invited to participate in the GRACE Science Team for the remainder of the GRACE mission,” he says, which he says is recognition of his expertise in the area.
Tregoning's next project is a successor to GRACE, who will shut down in about 2013. AU$4.6 million dollar grant is being used to develop a laser system for Australia to analyse the space orbit and process data from the satellites. “[I will be] developing parts of a laster ranging instrument to measure the changes in distance between the two satellites,” he says.
The successor will go into orbit in 2015, leaving a two-year gap in the information they are collecting. "There will be a year or two where we don't know what's happening" with gravitational movements around Earth, says Tregoning, and although this won't affect his work, it means there will be a period where there won't be up-to-date satellite information on climate change.
