Pressure is the most valuable surface observation for weather prediction since it provides information about the the deep atmosphere above. With pressure alone, meteorologists can determine the three-dimensional structures of the atmosphere. And pressure does not have exposure problems like wind or temperature...in a building, in a pocket, inside or outside, in the sun or not....it doesn't make much of a difference where the smartphone is located. It is the golden parameter. And meteorologists can make use of both pressure and pressure change to help start (or initialize) our weather forecasting models.
Imagine a world with a billion barometers
So we should get ready for a weather prediction revolution? Perhaps, but there is a major hurdle that must be crossed first:
The infrastructure for collecting this hugely promising weather data does not exist.
But at least one company has the potential to radically improve the situation: Apple Computer.
The question is whether Apple will help.
The iPhone 6 series (iPhone 6, 6+, 6S) have now sold over 150 million units around the world and remains the most popular smartphone in many markets. All have atmospheric pressure sensors.
By next year, 250 million iPhone 6's will be in use around the world.
To be useful, the pressure from the smartphone must be accompanied by position data from the unit's GPS. The history of movement of the phone would be help, as would its speed, which would tell us if it were in a moving vehicle.
Apple could assist in a number of ways in the collecting smartphone pressure data. Obviously, the best approach would be to build pressure collection into the operating system (iOS, which Apple control). Or pressure collection could be an option in the weather app that Apple preinstalls on every iPhone.
Want to see a shadow of what is possible? The Weather Channel app allows the collection of smartphone pressure and we were able to get a sample of their data---perhaps we are getting data from 1/1000 of the iPhone6s out there. Want to see what it gives us?
Let's start with a data rich country...the U.S. On the left are the convention observation locations over the Oklahoma area, on the right, from smartphones. Big enhancements You can even get pressures from smartphones on roads.
But the biggest advances might be in second and third world countries without a lot of weather data, such a India. Below is an image with conventional data on the left and smartphones on the right. Big enhancement. Many folks have smartphones in developing countries.
Smartphone pressures are also available from some Android phones (e.g., Samsung Galaxy series)--still waiting for a positive response from Google on my inquiries for help in pressure collection.
I have two graduate students working on the use of smartphone pressures for improvement of numerical weather prediction. We have some initially favorable results with a low density of pressure available from two small companies (Cumulunimbus Inc. and OpenSignal), but we really need more density to prove the value of the technology.
Where might dense pressures really help? We believe that large numbers of pressure might help forecast the initiation of thunderstorms. Or provide better short-term forecasts for wind turbines. Situations in which defining small scale weather features are important. And those are only a few of the potential weather features situation where smartphone pressures might help.
So Apple computer, please give me a call or email. Or leave a comment on this blog. You could potentially change the world of weather forecasting at little cost.