GPS Takes to the Skies for Weather

Using the technology of global positioning systems to track weather has been around for some time, but advances are continually being made that give experts more insight. Now, scientists at the Scripps Institute of Oceanography at the University of California San Diego have developed a new method that they hope will not only help track storms, especially hurricanes, but also help predict them well in advance of traditional methods.

The History of Tracking a Hurricane

Since the days of Noah’s flood, man has been intrigued by the forces of nature, both its causes and its effects. But man has struggled to anticipate the severity of a storm and get out of its way in time. Before the invention of the telegraph, the only warning coastline dwellers received of impending doom came from sailors fleeing a storm and searching for safe waters to anchor down. This gave people on land little time to prepare.

• 1844—The invention of the telegraph in 1844 made the approach of a hurricane only slightly less dire. Messages could be sent inland that a storm was advancing, so people had some time to board up windows or get to a basement; however, the number of casualties from storms was still quite high. The telegraph could not pinpoint a storm’s location or track its course.


• 1943—Not for another century would weather forecasters have a more precise picture of a hurricane’s anatomy. In 1943, a United States army pilot by the name of Colonel Joseph Duckworth accepted a bet that he could not fly into the eye of a hurricane. His feat paved the way for the hurricane-seeking aircraft used today. Known as Duckworth’s Dare, his stunt proved to scientists that there is indeed an air temperature discrepancy between the eye of the storm and the air surrounding it; in fact, according to the instruments in Duckworth’s single-engine AT-6 plane, there was a 25-degree discrepancy. This information helped weather forecasters better chart a hurricane’s strength.


• 1960—On April 1, 1960, NASA launched its first satellite specifically designated to monitor weather conditions. The TIROS, or Television Infrared Observation Satellite, provided the stunning pictures of swirling hurricane clouds often depicted in textbooks and on television. Such imaging helped meteorologists better track a storm’s movements but could not determine its intensity underneath the cloud cover.


• 1990s—At the end of the century, the U.S. Weather Bureau initiated the formal installation of a national hurricane warning system in three progressive stages. The first involved manned weather stations in the West Indies, Cuba, and Mexico. The second used ships at sea equipped with GPS receivers. And finally, the Bureau placed data buoys in the Golf of Mexico as well as the Pacific and Atlantic seaboards.

The Use of Aircraft in Tracking a Hurricane

The greatest advances in hurricane tracking have come with the airplane. After Duckworth’s Dare, hundreds of hurricane hunters took to the skies. Crews could drop sensors, known as dropsonde, into an already developed storm to record its wind speed and direction, its air pressure and temperature, and its altitude. But what if meteorologists could anticipate a storm in its most embryonic stage? That is what the researchers at Scripps under the direction of Jennifer Haase hope to achieve by placing GPS tracking devices on board commercial aircraft.

• Weaknesses of the old system: GPS receivers are typically fixed to the ground, so they cannot measure data accumulating out over the ocean. GPS-enabled satellites are expensive to launch, and they don’t usually orbit over storm-prone areas. And weather balloons are just launched too infrequently to be an up-to-date predictor. Current warning systems tend to issue alerts 24 hours before a storm makes landfall, but less than one-third of the area alerted will actually experience hurricane force conditions, which is why many people tend to ignore the warnings and decide to just weather the storm, sometimes with catastrophic results.


• Strengths of the new system: By placing GPS units on commercial aircraft, meteorologists have the potential of gathering data on a daily basis from hundreds of aircraft all over the world. Monitoring atmospheric conditions at different elevations and in targeted areas allows authorities to issue more specific and timely warnings. According to Jennifer Haase, “Having dense, detailed information about the vertical moisture distribution close to the storms is an important advancement, so if you put this information into a weather model it will actually have an impact and improve the forecast.”

Scientists call this new GPS-driven system GISMOS (GNSS [Global Navigation Satellite System] Instrument System for Multistatic and Occultation Sensing), and initial test results indicate an increase of more than 50% in the number of atmospheric profiles that meteorologists use to monitor a storm. “This is another case where the effective use of GPS has the potential to improve the forecast and therefore save lives,” said Richard Anthes, president emeritus of the University Corporation for Atmospheric Research. Though GISMOS is currently the size of a refrigerator, developers hope to get it down to shoebox size and placed on commercial aircraft in the very near future.

GPS Takes to the Skies for Weather