“[S]urface pressure is a uniquely valuable surface observation since it reflects the atmosphere above,” Mass writes on his blog.
Whether the barometric pressure data received by smartphones help advance weather forecasts depends on how effectively it is collected and incorporated into weather models. A citizen science weather app, Pressurenet.io, has been developed for crowdsourcing Android pressure data. It will be interesting to see if this effort now expands to pull in iPhone data.
Scientists who have examined smartphone weather data recognize errors in data measurement will need to be overcome. From a previous Capital Weather Gang post:
Even pressure, which seems to be the easiest measurement to gather from a cell phone, is wrapped in uncertainty. “If everyone stayed at sea level, pressure sensing would work well,” says [John] Celenza [lead software developer and meteorologist at Weather Underground]. Unfortunately, GPS can only estimate your elevation within an accuracy of about 60 feet, which translates to an error of two millibars. “This is a significant amount for weather,” he says.
While weather geeks love Apple’s inclusion of a weather measurement, the primary purpose of including the barometer is for determining elevation – which is useful for fitness nuts.
“[T]his information will appear in the iPhone’s Health app, tracking how often you climb stairs and other related metrics,” explains 9to5Mac.com. “The chip can also differentiate between running and walking distance.”