Seismic noise from storm surf provides new record of global warmings effect on stormsApril 22nd, 2008 - 3:15 pm ICT by admin
Washington, April 22 (ANI): Seismologists have discovered a trove of seismic noise from storm surf that provides a new record of global warmings effect on storms.
According to a report in Discovery News, the pounding of storm waves on any shore creates vibrations in the Earth that can be heard by seismometers and translated into storm power.
The archived seismological data now show that this wave energy has been getting stronger for decades, matching whats predicted to happen as the worlds oceans and air heat up.
An analysis of decades of digital seismic data at 22 seismic stations worldwide shows that the power of most powerful storm waves is on the rise in every case.
For decades, the seismic signals from ocean waves were considered mere noise to seismologists. But then researchers like seismologist Rick Aster, Peter Bromirski and Dan McNamara started mining that noise for information.
Weve got a really remarkable record in the seismological community, said Aster.
Its a record developed for entirely different purposes, but now has surprising applications.
The ocean wave effect that is easiest to see in the seismic record is called the global oceanic microseism. This signal is made of seismic waves that take anywhere from 5 to 30 seconds to rise and fall.
We can see very clearly wave effects, Aster explained.
Seasonal changes in storm tracks, hurricanes and El Nino-driven cyclones are also easy to pick out. Of these, groups of swells striking shorelines can be seen clustered in the seismic charts - each one spawned by the winds of a particular storm.
The stations with the most sensitivity are in the North Atlantic and the North Pacific and coastal, said Aster.
Hawaii is the best station of all, since it is surrounded by shorelines and picks up swells from storms all over the Pacific Ocean.
In this particular study, Aster and his colleagues tried to single out just the most powerful storms - those with winds of at least 55 miles per hour.
As for what this says about global warming, its some confirmation of the meteorological effects of climate change, but its too short a record, in itself, to make a separate case for global warming.
Its an interesting way of looking at it, but Id like to see more data, commented David Salzberg, a private industry seismologist. (ANI)
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