Despite the sensor’s prevalence—a good chunk of the nearly 3 billion smartphones in the world now have one—meteorologists haven’t yet been able to take full advantage of its potential.
Developers and weather forecasters have been talking about using smartphone sensors for years, but neither Apple’s iOS nor Google’s Android operating systems make available the pressure readings taken by their smartphones. And so far, weather apps have only been moderately effective in harnessing the smartphone sensors.
Last year, a popular weather app called Dark Sky introduced an opt-in feature that automatically takes barometric pressure readings. “We get more than a million pressure sensor reports a day, and it’s growing,” said Dark Sky’s founder, Adam Grossman, in an email. “We’re still very much in the experimentation phase when it comes to using the data, but we’re optimistic that it’ll be used in our forecasting in the not-too-distant future.”
Another app, WeatherSignal, takes automatic readings and sends it to a number of academic partners, according to Brendan Gill, the app’s founder. One of those partners is Cliff Mass, a professor and meteorologist at the University of Washington, who has been writing about the potential of smartphone readings to change weather forecasting on his blog and in academic journals since 2012.
For now, Mass says, he gets about 5,000 to 10,000 readings an hour from WeatherSignal, which he’s combined with a few other data feeds—including one from an app coded by one of his grad students—to fine-tune the algorithms he’s developed to simulate weather patterns.
Pressure observations are particularly useful for figuring out traditionally hard-to-predict weather events, said Mass—detailed pressure readings might reveal the atmospheric subtleties that tend to precede a storm, for example. The data could also help lead to better predictions of shifts in the winds. “Errors of an hour or two in timing in a wind shift line could be worth huge amounts of money for wind farms,” Mass said.
But to be successful, researchers need a whole lot more readings, especially in less populated areas in places like the Midwest.
“What we’ve shown is that even moderate density helps. But I’d like to have a whole order of magnitude—or two orders of magnitude or three orders of magnitude—more observations, and I’m hoping that could provoke revolutionary improvements in forecasting these smaller-scale features,” said Mass. “If I could get a density of one [sensor] per square mile in rural areas, that would be a big advance.”
Last year, Mass spoke extensively with Google about harvesting barometric data from the vast network of pressure sensor-equipped Android smartphones for his research. The talks got a long way, he said, but ended up falling apart. Google was not immediately available for comment.