What if, every day, a global network of students collected and shared measurements of small solid and liquid particles suspended in the atmosphere? Known as “aerosols” these tiny particles are important because some of them cool Earth’s climate, and some of them impair human health. And yet, scientists don’t know the full extent of aerosols’ influence on our planet. Having a community of students collect data about aerosols in geographically dispersed places around the world might contribute significantly to scientific understanding. But can students collect data accurate enough for professional-quality research? Pieternel Levelt, Principal Investigator for an instrument on NASA’s Aura satellite, believes the answer to this question is yes.

In 2000, Levelt was approached by David Brooks, Research Associate Professor in the Department of Mathematics and Computer Science at Drexel University, with the idea of forming a student-scientist partnership for data collection. Brooks works with GLOBE,—an international science and education program established by a group of U.S. government agencies in which thousands of students all over the world routinely collect and share their measurements of many different aspects of Earth’s environment. Brooks serves as Principal Investigator for GLOBE’s Aerosol Monitoring Project. GLOBE students use handheld devices called Sun photometers to measure aerosol concentrations. Students participating in this investigation collect and publish their aerosol data on the Web so their fellow students and scientists all over the world may use them.

GLOBE students carefully follow protocols established by scientists in order to collect accurate data. But many scientists who have not been involved with GLOBE question the validity of student-gathered data for professional science investigations and are reluctant to use the data. The GLOBE program has been fighting this negative perception among scientists ever since it began in the early 1990s.

Pieternel Levelt believes that high school students can collect scientifically valuable data to help validate her satellite-based measurements of small liquid and solid particles suspended in the air (aerosols). Many scientists doubt the usefulness of student data. In 2003, Levelt and colleagues conducted some experiments to resolve the issue. (Photograph courtesy Pieternel Levelt)

Levelt quickly warmed to Brooks’ idea of a student-scientist partnership, however, because she realized what a valuable contribution students could make to her research, and she wanted to encourage more young people to participate in science. “Originally, we wanted to join this program because in the Netherlands we see fewer and fewer young people, especially girls, interested in science,” explains Levelt, who conducts research at the Royal Dutch Meteorological Institute. “In GLOBE, I saw a program that looked like it would be fun for students, and would get them involved with a satellite mission that could be a type of work they could do after they graduated.”

Aerosols present scientists—and students—with important and multi-faceted problems. Some aerosols cool the surface of our planet, while others exert a warming influence. Aerosols also affect the weather by enhancing or inhibiting cloud formation, leading to flood-causing rainstorms in some regions and drought in others. Aerosols also impact human health. When people inhale them into the lungs these particles make it hard to breathe, and they can cause cancer. Understanding the locations, amounts, kinds, and multiple effects of aerosols has become a critical area of research for Levelt and many other atmospheric scientists.

Satellite observations enable global-scale observations of aerosols. A sensor called the Ozone Monitoring Instrument (OMI) launched into orbit on the Aura satellite on July 15, 2004, collects aerosol data every day all over the world. Levelt is the Principal Investigator for OMI. As part of its Earth Observing System (EOS) mission protocol, NASA requires all instrument teams to validate their remote sensors. In other words, instrument teams must demonstrate that the sensors’ measurements are accurate within a specific margin of error. Validating satellite remote-sensing measurements is demanding, extensive work and requires precision. If the data are not validated, scientists will consider them useless for doing “real” research. Understandably, NASA satellite mission managers take validation very seriously.

As a practical matter, it isn’t feasible for scientists to make as many measurements at ground level for validation as they would like. Some desirable validation sites are remote, far apart, or inaccessible for a multitude of other reasons. As Levelt was developing her plan for validating OMI aerosol data, her Ph.D. student Folkert Boersma had a brainstorm—why not use the students’ GLOBE data to validate OMI’s aerosol measurements? Most scientists would have considered the idea preposterous. But Levelt liked it.

“That’s when we got serious about the idea,” she recalls. But the question remained: would the students’ data be reliable and accurate enough? Could she depend on both the GLOBE instrument and the students’ mastery of data collection procedures as contributions to her professional work?

 Students to the Rescue

A teacher and two students from De Blaucapel, a school in Utrecht, learn to operate the GLOBE Sun photometer at the Royal Dutch Meteorological Institute (KNMI). Scientists have established protocols and developed inexpensive sensors that enable student participation in research. (Photograph courtesy Joke van de Bovenkamp, KNMI)