Tags: Satellite Positioning, GPS, Volcano, GPS Signal
Publication: ScientificAmerican.com
Publication Date: 05/30/2013

Volcanic ash-filled cloud from Icelandic volcanoe Grimsvötn. Image credit: Kris Olin

A research published in the Geophysical Research Letters journal could indicate the possibility of a new technique to track dangerous ash-filled clouds using GPS. Early detection of these hazardous clouds could help avoid or minimize a situation such as the one created after the Grímsvötn volcano in Iceland erupted two years ago leading to cancelled flights all over Europe.

According to the study, signal-strength data logged in the inner workings of GPS machines is usually ignored since the main purpose of the machines is to calculate location. However, during a research effort to measure how terrain shifts during a volcanic eruption, scientists found how the volcano’s ash blocked GPS signals used for the study. Realizing this, researchers were able to track the cloud in real time by observing the strength of the GPS signals in different areas. Once it passed, the signal went back to its normal levels.

The technique provides a more accurate tracking method than radar or satellite imagery, according to the study. Satellite images are basically useless to track a volcanic cloud if it’s cloudy, and radar technology is expensive. GPS is essentially unaffected by clouds or water vapor, and it is significantly cheaper.

However, more research is needed to determine how dense the cloud has to be to cause a drop in GPS signal strength. And, more global satellite positioning satellites would be needed to effectively monitor all active volcanoes.

 Full story