An Australian physicist has developed satellite technology that measures the world's freshwater reserves from space. The technology is at the heart of the NASA's Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, which launched last month, and follows the first GRACE mission which launched in 2002. 

The launch was particularly stressful for Australian physicist Daniel Shaddock from the Australian National University as 15 years of his work was onboard the rocket. "It was a little bit surreal," Professor Shaddock said. "So many years of your life working on something — it was hard to believe it was actually happening and finally launching.

Professor Shaddock developed a retroreflector that uses lasers to measure the world's water reserves from space with unprecedented accuracy. "It measures something that's really important; the presence of water — whether that's frozen form or liquid form — across the entire globe at once. And that's something you can only do from space. "Any large body of water will generate gravity and that gravity can be picked up by GRACE."

GRACE has the extraordinary ability to peer beneath the Earth's surface to weigh groundwater reserves where a third of all freshwater lies.

Australian National University water expert, Albert Van Dijk, said the first GRACE mission painted a disturbing picture of freshwater loss. Professor Van Dijk said in populated, arid parts of the world such as India, huge amounts of water is being pumped out of the ground. "What GRACE is telling us is that a lot of that groundwater is not being replenished," Professor Van Dijk said. "We're actually mining groundwater and the magnitude of that is actually quite impressive. "The direct consequence is the groundwater table goes lower and lower and farmers have to deepen their wells."

In Australia, GRACE has shown groundwater levels in the Murray-Darling Basin still have not recovered from the Millennium Drought, which ended in 2011. The mission also revealed that freshwater is disappearing from Greenland and West Antarctica faster than any other place on Earth as ice caps melt.  "GRACE is giving us solid numbers about how much ice is disappearing, how much is ending up in the oceans and also how it's changing our water cycle and our water resources.

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Article source: ABC News