Australia: Australian researchers will use GPS signals to determine how much water is in the atmosphere, and help create more accurate climate models and predictions. Melbourne”s RMIT University plans to use numerical weather prediction models and atmospheric re-analysis products to provide data needed to calculate water vapour content from GPS observations.
The researchers will tap into an unused part of the GPS signal that often is discarded as “noise” to determine how much water vapour is in the atmosphere.
When a GPS satellite sends out a signal, the time it takes to travel to a receiver on Earth depends on the conditions of the atmosphere.
The interference creates “noise” in the signal, which needs to be removed to give an accurate position. By knowing the surface temperature and air pressure at the site of the receiver, scientists can work out how much water vapour is present.
RMIT lecturer and researcher Suelynn Choy will investigate if data from Geoscience Australia and the Bureau of Meteorology (BOM) can be combined to give a record of atmospheric water content.
Water vapour is seen as the most abundant greenhouse gas in the atmosphere and is responsible for more warming than any other gas, such as carbon dioxide.
By including water vapour in climate models, scientists will be able to better predict the impact of future warming on Australia.
Dr Choy, who has received a scholarship to undertake the proof-of-concept study, will focus on assessing the quality of the GPS-derived water vapour data and developing a method for processing the observations.
“It will provide an additional source of information because at the moment to get water vapour information is not easy,” she said.
If successful, scientists will have access to more than 10 years of GPS-derived water vapour data and observations from across Australia and Antarctica to fill a void in data used to produce climate models.
“Hopefully, this information will be used by the BOM for their climate studies to see how the water vapour content has changed in the past 10 years in the Australian region,” Dr Choy said, adding that the research could provide a supplementary atmospheric sensing tool for climate studies with applications in Australia and globally.
Source: The Australian