Researchers are taking advantage of the hidden and not-so-hidden features of off-the-shelf smart phones and tablets to improve weather forecasts and keep tabs on the amount of particulates in the air – as well as perform more-routine tasks such as tracking changes in vegetation with the seasons or monitoring the water level in streams.
The goal is to develop apps and inexpensive add-ons that allow a growing army of citizen scientists to gather the data that researchers are seeking but don't have the time or graduate students to gather.
The term crowdsourcing may be relatively new, but in the world of science, enlisting the help of people outside academia to help with research isn't. Still, it is changing character.
Amateur astronomers have long helped their professional colleagues with observations that the professionals didn't have time to gather themselves. With the advent of personal computing, people could turn their PCs into number crunchers for climate modelers, cellular biologists, and researchers sifting through signals from radio telescopes in hopes of finding E.T.
The widespread popularity of smart phones and tablets, which host powerful processors and lots of memory to accommodate still and video cameras (in addition to making phone calls), means that researchers have a potentially huge army of data hounds. If willing to add an app, or in some cases a small clip-on device to their phone, these people can provide important environmental data at a more fine-grained level, over a wider geographic reach, and potentially over longer periods of time than any one researcher or team of researchers might gather, notes Sandra Henderson, director of citizen science for the National Ecological Observatory Network (NEON) and cofounder of Project BudBurst.
Tapping the mobile technologies in people's purses and pockets to support basic or applied research has been gaining momentum over the past couple of years, Dr. Henderson says. Project BudBurst enlists anyone interested to use their smart phones to track the life cycle of key plant species throughout the year to help researchers monitor the impact of a changing climate on vegetation.
Given the advances in phone capacity and capabilities, she also says she foresees apps that can share information between different observations, so that a photo of a bursting bud tagged with location information from the phone's GPS receiver also carries information gleaned from an app that uses sensors on the phone to record weather conditions at the time the bud opens – or perhaps for a week or more prior to the bud's opening.
"We're on the cusp of that," she says.
Some features, such as built-in cameras and GPS receivers, have obvious applications for recording when a tree first opens its leaves or what the height of water is as it passes along a stream gauge.
Other potential tools are less obvious and require a eureka moment or two.
For instance, OpenSignal, a company in Britain that has developed an app for finding the best Wi-Fi or cell signal given your location, was reviewing its data about a year ago to see what impact the use of 3G or 4G networks had on drawing down a phone's battery.
One clue came from readings taken by a phone's temperature sensors, which phones carry to sense whether a battery is being overcharged.
"We found a really strong correlation between battery temperature and historic daily temperatures," says James Robinson, the company's cofounder and chief technology officer.
In addition, smart phones can measure light intensity and the intensity of magnetic fields. And with the newest offerings from Samsung, phones have included dedicated air-temperature and humidity sensors.
As OpenSignal took time off to develop an app for that, Dutch meteorologists from Wageningen University and the Royal Netherlands Meteorological Institute contacted the company about its cell-coverage app, which could be of value as the researchers developed a method for using signals traveling between cell towers to monitor rainfall intensity and the movement of squalls across the countryside.
When Mr. Robinson showed the researchers the temperature data, the scientists worked up an approach that tried to infer outside temperature by using the battery temperature. In essence, it's a proof-of-concept calculation. So far, the temperatures are off by about 2.7 degrees F.
The next steps are to find ways to reduce the difference, which means accounting for confounding factors, such as the thermal properties of the various phone cases, or whether the phone is actually exposed to open air or is taking readings while inside a pocket or purse.
The team, which included Robinson, was led by Aart Overeem, a hydrologist at Wageningen University. The results of the team's initial experiments have been accepted for publication in the journal Geophysical Research Letters.
The notion of using cellphones to record temperatures is of intense interest in improving forecasts for urban meteorology, in which heat rising from city surfaces can boost temperatures by several degrees, especially at night. Having temperature readings from thousands of locations would allow energy or emergency managers to build temperature maps that would allow them to anticipate energy demand or more efficiently allocate resources to areas where the heat is greatest and the population most vulnerable, the researchers say.
The biggest boon to local or regional weather forecasts could well come merely from the pressure sensors inside smart phones, says Cliff Mass, a professor of meteorology at the University of Washington in Seattle who is pioneering the incorporation of cellphone air-pressure measurements into forecast models.
"This could really be a major advance for forecasting," he writes in an e-mail.
Cumulonimbus, a Canadian company, has produced a free app that records barometric pressure on Android smart phones that have barometers. The data are shared with scientists.
Dr. Mass and colleague Luke Madaus have incorporated the data from these apps to produce forecasts of highly localized weather events or the routine passage of larger weather fronts in the Seattle area. The forecasts are more accurate than those lacking the additional measurements. The benefit comes from having a far more dense network of barometers than the National Weather Service and its cooperative observers can provide.
"The results look promising," Mass said during a presentation of the concept earlier this month at a conference sponsored by the American Meteorological Society. Given the number of smart phones and tablets in use, he added, that translates into millions, if not tens of millions, of barometers across America with data just waiting to be tapped.
Meanwhile, in the Netherlands, researchers at the Leiden Observatory and two other national research institutions have developed an app for iPhones that turns the phone into a mini spectrometer to take the measure of tiny particles known as aerosols in the atmosphere. Under the project, known as iSPEX, users slip a small unit over the phone's camera lens to break up the light into its components, as well as measure the light's polarity. The app records and sends the results to the research team heading the project.
Other small add-ons could follow suit, researchers say.
With new opportunities opening as smart phones get smarter and sense their environment in new ways, the potential for helping researchers better understand how that environment works and how it's changing will increase dramatically, Henderson of NEON suggests.
"The real power of these things is that we can look at things, maybe not as in-depth" as scientists studying a single small site for 30 years, "but we can put out numbers" over much wider spaces, over long periods of time, that wouldn't be possible otherwise, she says.