The National Aeronautics and Space Administration (NASA) is working on a tsunami detection system -GUARDIAN – which can detect the ‘ocean’s deadliest waves’ from the far reaches of atmosphere. The space agency’s Jet Propulsion Laboratory (JPL) scientists are working on the the monitoring system that is set to coordinate with the data from clusters of GPS and other wayfinding satellites oribting our planet.
The tsunami that occurred on December 26, 2004 was just hours after an earthquake of magnitude 9.0 shook the floor of the Indian Ocean. Then scientists had no way to warn officials or the public about the deadly waves which hit the shore across Bay of Bengal and took away 2,20,000 lives.
So, GUARDIAN, as scientists say can also be used as a “lifesaving alarm bell” by exploring the use of navigational satellite systems to enhance early warning strategies. Though still maturing, the system is already one of the “fastest monitoring tools” of its kind: Within 10 minutes it can produce a kind of snapshot of a tsunami’s rumble reaching the ionosphere. And it could potentially provide as much as “an hour of warning”, depending on the distance of the tsunami origin from shore.
How does it work?
According to NASA’s official website, GUARDIAN (GNSS upper atmospheric real-time disaster information and alert network) utilises the signals from global navigational satellite systems (GNSS) to detect the occurrence of tsunamis worldwide. The monitoring system collects clusters of these signals, which are transmitted to numerous scientific ground stations globally. JPL’s Global Differential GPS (GDGPS) network processes this data, enhancing real-time positional accuracy to a few inches (approximately 10 centimeters).
When tsunami is about to hit
-During a tsunami, a large area of the ocean’s surface experiences synchronized rising and falling, leading to the displacement of a significant volume of air above it.
-This displaced air generates low-frequency sound and gravity waves that propagate in all directions.
-Within a few minutes, these waves reach the ionosphere, the topmost layer of the atmosphere, which is electrically charged and affected by solar radiation.
-The interaction between the pressure waves and charged particles in the ionosphere causes slight distortions in the signals transmitted by nearby navigational satellites.
-Typically, navigation systems aim to correct such disturbances in the ionosphere, but scientists have recognized that the data resulting from these disturbances can be utilized to identify natural hazards.
Where is GUARDIAN’s focus now?
Currently, GUARDIAN’s team is focussing on the Ring of Fire, a region in the Pacific Ocean known for its geological activity. According to the historical database maintained by the National Oceanic and Atmospheric Administration (NOAA), around 78 per cent of the confirmed tsunamis between 1900 and 2015 occurred in this area.
GUARDIAN’s monitoring coverage in the Pacific currently extends to slightly over 50 per cent of the region of interest.
The GUARDIAN team is currently working on the development of a website that will enable experts to examine the state of the ionosphere in nearly real time.
Through this website, users will have access to data from approximately 90 stations located around the Pacific Ring of Fire. They will be able to quickly identify noteworthy signals shortly after an event takes place.
The team is aiming to enhance the system’s coverage and accuracy, to the extent that it can automatically detect and alert for tsunamis as well as other hazards such as volcanic eruptions and earthquakes.
