If Marshall McLuhan had been a rocket scientist, he might have liked PlanetIQ’s approach to forecasting the weather. It uses signals from GPS satellites, but not for positioning. Instead, it measures distortion in these signals to learn about the atmosphere through which they passed. To quote McLuhan out of context, the medium is the message in this case: the manner of acquiring the information is more important than the information itself.
PlanetIQ sees an opening for itself because the United States network of weather satellites is aging and the replacement satellites are delayed and over budget. So PlanetIQ, a start-up based in Bethesda, Md., is using a physics trick to get information from existing satellites and plug it into computerized weather models.
The company wants to put 12 tiny satellites into orbit that will do nothing except watch the GPS satellites rise and set on Earth’s horizon. The signals sent from these satellites are bent by the atmosphere at an angle that indicates the air’s temperature, pressure and water vapor content. PlanetIQ’s satellites can determine the angle because the way the signals are bent delays their arrival. The GPS signal already encodes the time at which it was sent; the time it should have arrived had there been no bend can be computed if one knows the distance the signal was supposed to have traveled.
“GPS is a giant timing system,’’ said Anne Hale Miglarese, PlanetIQ’s president and chief executive.
The idea, called radio occultation, has great promise, according to experts. “There’s definitely a lot of interest,’’ said Crystal B. Schaaf, a professor of remote sensing at the University of Massachusetts, Boston. “Anything that gives us any information about the atmospheric profile is a godsend when you’re trying to trigger numerical prediction models.’’
“As meteorologists, we’ve relied for many years off launching weather balloons and getting these far-separated points,’’ Professor Schaaf said, adding that satellite observation would provide much more data.
In PlanetIQ’s system, each satellite would take 1,000 readings a day from the GPS satellites, with each reading measuring the temperature and pressure of the slice of Earth’s atmosphere through which the signal traveled. The fleet would generate about 5.5 million readings a day, which would be integrated by a computer on the ground into a 3-D map of atmospheric data.
PlanetIQ would also measure the earth’s magnetosphere, which indicates when a solar storm is in progress. Such storms can threaten power grids and other terrestrial activity.
The atmospheric measurements would not allow for much weather forecasting on their own, but they could supplement data from other sources to make forecasts more precise, Ms. Miglarese said.
Peter J. Minnett, chairman of the meteorology and physical oceanography department at the University of Miami, said that GPS receivers of the kind PlanetIQ proposes would probably be included in future weather satellites, but that it would take time to put a significant number in use. And the ability to launch new satellites as fast as the old ones decay is no longer assured, he said, because governments have limited resources.
Professor Minnett added that the idea of a commercial company collecting data and selling it to the government would be a shift from the current approach, in which agencies like NASA and the National Oceanic and Atmospheric Administration gather the data and exchange it freely.
Commercialization is always tricky. PlanetIQ says it needs $160 million to get its satellites in orbit. To raise that money, it probably needs contracts with national weather services.
It is seeking to sign up NOAA, the parent agency of the National Weather Service, as an “anchor tenant†for its system. But so far, NOAA has been noncommittal.
A spokesman said, “We welcome any reliable data that helps the National Weather Service meet its mission requirements while also being cost-effective and properly reflected in our budget.â€
