Guardian is a new experimental monitoring system from NASAwhich uses data from groups of GPS satellites and other orientation satellites orbiting our planet to anticipate tsunamis.

Collectively, these groups are known as Global Navigation Satellite Systems, or GNSS. The radio signals go to hundreds of ground science stations around the world.and that data is processed by JPL’s Global Differential GPS (GDGPS) network, which improves real-time position accuracy to within a few centimeters.

Due to earthquakes, submarine volcanoes and other earthquake forces, tsunamis can devastate coastal communities. And when it comes to early warning, every second counts.

For this reason, scientists at NASA’s Jet Propulsion Laboratory are testing this new method to, from the confines of the atmosphere, the deadliest waves in the ocean.

The new system filters the signals for signs that a tsunami has occurred somewhere on Earth.

How does it work?

During a tsunami, many square miles of the ocean’s surface can rise and fall almost simultaneously, displacing a significant amount of air above it. The displaced air ripples in all directions in the form of low-frequency sound and gravitational waves. After a few minutes, these vibrations reach the upper layer of the atmosphere: the ionosphere, electrically charged and baked by the sun. The resulting collision of pressure waves with charged particles can slightly distort signals from nearby navigation satellites.

Although navigation instruments usually correct for these ionospheric disturbances, scientists can use them as alarms to save lives, says Léo Martire, JPL scientist developing Guardian (GNSS Upper Atmospheric Real-time Disaster Information and Alert Network). “Instead of correcting this as an error, we use it as data to find natural hazardssaid Martire.

According to Martire, who co-chairs a United Nations International Commission on GNSS working group that is researching the use of satellite navigation systems to improve early warning strategies, the technology is still evolving.

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 surveillance tools of its kind: in 10 minutes it can take a kind of snapshot of the roar of a tsunami hitting the ionosphere. And it can provide up to an hour’s warning, depending on the distance from the tsunami source to the coast.

The Guardian team is currently focused on the most geologically active area of ​​the Pacific Ring of Fire. 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 this Pacific region of interest.

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The Guardian team is developing a website that will allow experts to explore the state of the ionosphere in near real-time by studying individual links of GNSS network satellite stations.

Users can access data from some 90 stations around the Pacific Ring of Fire and discover interesting signals within minutes of an event.

The team’s goal is to expand coverage and refine the system until it can automatically detect tsunamis and other hazards such as volcanic eruptions and earthquakes.