June 1 () –
A new experimental monitoring system from NASA harnesses GPS data and other location satellites to anticipate tsunamis up in an hour ‘listening’ to its noise in the atmosphere.
Called GUARDIAN (GNSS Upper Atmospheric Real-time Disaster Information and Alert Network), it is based on the data processing of the Global Differential GPS (GDGPS) network of the JPL (Jet Propulsion Laboratory) of the space agency, that improves the positional precision in real time up to about 10 centimeters.
The new system sifts through the signals for clues that a tsunami has erupted somewhere on Earth. How does it work? During a tsunami, many square kilometers of the ocean surface can rise and fall almost in unison, displacing a significant amount of air above. The displaced air propagates in all directions in the form of low-frequency sound and gravity waves. In several minutes, these vibrations reach the upper layer of the atmosphere: the electrically charged ionosphere baked by the Sun. The consequent collision of pressure waves with charged particles can very slightly distort the signals from nearby navigation satellites.
While navigation tools generally seek to correct for such ionospheric disturbances, scientists can use them as a life-saving alarm bell, said Léo Martire, the JPL scientist developing GUARDIAN. “Instead of correcting this as a mistake, we use it as data to find natural hazards,” Martire said. it’s a statement.
The technology is still maturing, Martire said. Currently, GUARDIAN’s near real-time results must be interpreted by experts trained to identify tsunami signals. But it’s already one of the fastest monitoring tools of its kind: in 10 minutes it can produce a kind of snapshot of the roar of a tsunami hitting the ionosphere. And it could potentially provide up to an hour’s warning, depending on the distance of the tsunami origin from the coast.
At this time, the GUARDIAN team it is focused on the geologically active Ring of Fire in the Pacific Ocean. About 78% of the more than 750 confirmed tsunamis between 1900 and 2015 occurred in this region, according to a historical database maintained by the National Oceanic and Atmospheric Administration (NOAA). GUARDIAN currently monitors just over half of the region of interest in the Pacific.
