Scientists from the Satellite Positioning for Atmosphere, Climate and Environment (SPACE) Research Centre at RMIT University and the Australian Government Bureau of Meteorology have adopted an alternative use for the global positioning system (GPS) technology which is already used to power satellite navigation tools.
Combining GPS with data from low earth orbit satellites, the team produced another input source for the complex computer models used to help meteorologists forecast the weather. These computer models utilise around ten billion current observations from 30 to 40 complementary instruments in order to generate their information.
"What we’ve found through our work with RMIT’s SPACE research team is that the GPS data improves the real-time temperature field and the cross-calibration of the data from a number of satellite instruments," said RMIT Adjunct Professor John Le Marshall, research programme leader at the Bureau of Meteorology. "This in turn significantly increases the usable quality of the satellite observations."
"We are actually able to measure the amount of bending in the GPS beam as it passes through the atmosphere," Professor Le Marshall continued. "We can then use that knowledge to more accurately measure atmospheric temperatures and use this to improve temperature fields and calibrate other satellite readings. This extra information, in the data-sparse southern hemisphere, is now making our forecasts more accurate."
Dr Kefei Zhang, Director of the RMIT SPACE Research Centre, expressed the belief that, as a revolutionary technology, GPS has transformed the fields of Positioning, Navigation and Timing (PNT) and continues to help fill gaps in our knowledge.
"Weather forecasting is dependent on accurate observations of the atmosphere surrounding the whole planet, but there is a significant lack of ground-based meteorological observation stations," explained. "That and the shortage of accurate surface level data from over the world’s oceans and polar regions limits the reliability of climate and weather predictions. This is particularly true for Australia, where people live along long coastlines but forecasters can only draw on very limited measurements from the middle of the continent and surrounding oceans."
In the future, GPS data could play a more influential role in severe weather warnings and climate monitoring, but for now it is being used to provide accurate forecasts more quickly.
"Since the research was completed and began being used in forecasts this year, we estimate the Bureau is now delivering forecasts of the same accuracy 10 hours earlier," said Professor Le Marshall.