Tsunamis Are Detected in the Atmosphere by NASA Researchers
New Hazard-Monitoring Technology Using GPS Signals to Find Waves in the Pacific Ring of Fire.
The GUARDIAN (GNSS Upper Atmospheric Real-time Disaster Information and Alert Network) system was developed by scientists at NASA‘s Jet Propulsion Laboratory. Its primary goal is to supplement existing early warning systems by detecting tsunamis and other natural disasters that originate in the Pacific Ring of Fire.
The system uses data sent by clusters of GPS and wayfinding satellites known as global navigational satellite systems (GNSS). These satellites transmit radio signals to a network of scientific ground stations across the world, and the data is processed by JPL’s Global Differential GPS (GDGPS) network, which improves real-time positioning accuracy to a few inches.
GUARDIAN analyzes the GNSS signals to detect signs of a tsunami. Large portions of the ocean surface suffer synchronous rise and fall during a tsunami, displacing a substantial volume of air above them. This displaced air spreads in all directions as low-frequency sound and gravity waves.
The quickest monitoring tool of its kind
In minutes, these waves reach the ionosphere, the topmost atmospheric layer that is electrically charged due to solar radiation. As a result of the interaction between pressure waves and charged particles, the signals of neighboring navigational satellites are slightly distorted.
While traditional navigation technologies typically correct these ionospheric disturbances as errors, GUARDIAN uses them to identify natural risks. The technique gives a near-real-time snapshot of the tsunami’s influence on the ionosphere within approximately 10 minutes by deciphering tsunamis-induced disturbances. GUARDIAN can provide up to an hour of prior notice depending on the distance of the tsunami’s origin from the coastline.
GUARDIAN is now one of the fastest monitoring tools of its kind, but it is still in the early stages of development. Its result requires interpretation by tsunami detection experts. The system is intended to supplement existing ground- and ocean-based instrumentation, such as seismometers, buoys, and tide gauges, which only partially cover part of the ocean.
NASA’s Disasters program already uses GNSS stations in several locations for rapid tsunami detection, and GUARDIAN plans to expand on these capabilities.
The GUARDIAN team
The GUARDIAN team’s principal emphasis is the Pacific Ring of Fire, a region noted for its geological activity and the location of 78% of confirmed tsunamis between 1900 and 2015. GUARDIAN currently monitors slightly more than half of the Pacific region of interest.
The team is also working on a website that will provide specialists with near-real-time data on the state of the ionosphere. Individual satellite station links on the GNSS network can be explored by anyone, providing data from roughly 90 sites around the Pacific Ring of Fire.
The team’s ultimate goal is to broaden coverage, improve the system, and enable automatic detection of tsunamis and other threats, such as volcanic eruptions and earthquakes.
Read the original article on PHYS.
Read more: Modified Eggs May Lead To The End Of Allergies.
