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CNR: Alamanacco della Scienza


N. 11 - 20 giu 2012
ISSN 2037-4801

International info   a cura di Cecilia Migali


Gps for weather forecasting

Researchers at Rmit University's Space Research Centre (Melbourne, Australia) and the Bureau of Meteorology are using Gps and low earth orbit satellites to provide an additional type of temperature profile observation for use in weather forecasting computer models.

The computer models draw on about a hundred thousand million current weather observations, including data from 30 to 40 complementary satellite instruments, to generate the information used by meteorologists to prepare weather forecasts.

Rmit Adjunct Professor John Le Marshall, Research Program leader at the Bureau of Meteorology, says: "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. 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. 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".

Professor Le Marshall says that "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".

He predicts that, as techniques improve, Gps data will also play a bigger role in climate monitoring and severe weather warnings.

Professor Kefei Zhang, Director of the Rmit Space Research Centre, said that Gps as a revolutionary technology for Positioning, Navigation and Timing (Pnt), provided a low-cost, powerful means of precise measurement of the earth environment.

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. 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.

"Gps can fill that gap. It's revolutionary technology. It's the missing link", Professor Zhang says.


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