Newswise — This is a continuing profile series on the directors of Department of Energy (DOE) Office of Science user facilitiesExternal link. These scientists lead institutions that provide researchers with the most advanced tools of modern science including accelerators, colliders, supercomputers, light sources, and neutron sources, as well as facilities for studying the nano world, the environment, and the atmosphere.

Settled into a cramped seat on a commercial flight, Jim Mather can't resist looking out the window at the clouds. It's an occupational hazard when your job revolves around the atmosphere. Mather directs the Department of Energy's (DOE's) Atmospheric Radiation Measurement user facility (ARM)External link, a far-flung set of observatories that gather data to advance atmospheric and climate research.

"Flying out of New Orleans in 2017, there was this totally clear blue sky and a line of clouds that went on for hundreds of miles," said Mather. "You see interesting phenomenon like that and it gets your attention. I often look out the airplane window and wonder how you would model that."

Earth system models let scientists study interactions between different systems, such as the atmosphere and the ocean. Whether they're thunderstorm anvils or wispy mare's tails, clouds are a vital part of the model, but measuring clouds, getting data, is notoriously difficult. "Clouds are pretty complicated beasts," said Mather.

That complex nature starts with the spatial scales involved. Cloud droplets form on tiny aerosol particles, about a micrometer in size. For comparison, the particles are a thousand times smaller than the ant at your last picnic. "These particles form slightly larger droplets and then larger rain drops. Populations of cloud droplets make up clouds and then cloud systems, like Hurricane Florence," said Mather. "All of these things interact. It's a huge puzzle. It's hard to get bored with that."

To model clouds and refine Earth system models, scientists need data. Getting that data is what ARM has done since it began more than 25 years ago. Mather's been with ARM since just after it started.

Mather's career path takes him to the tropics and the director's office

When he finished his doctoral degree in meteorology at Pennsylvania State University, he heard about an opportunity with the ARM team establishing a cloud observatory on ManusExternal link, a remote island off the coast of Australia. The observatory would gather data about El Niño and other tropical phenomena with global impacts. "I was a post-doc at the time," said Mather. "My job was to assess the data coming from the instruments to make sure they were working properly."

As the team set up the observatory, Mather spent five weeks working on the island. He set up instruments, examined data, and helped dig trenches among thatched huts, mosquitos, and palm trees. He worked with ARM's other tropical sites for three more years. But the constant travel got him thinking about other careers. He took a job teaching physics and meteorology at a liberal arts college in Wisconsin. After two years, he missed the scientific community. "To be able to participate in some of these ARM workshops and talk with researchers from around the world is pretty amazing," said Mather. "There's a lot of talented people around."

In 2001, he left Wisconsin for his second stint at ARM and hasn't looked back. He worked as the associate site scientist for ARM's tropical sites. He also conducted research on several field campaigns. Then, in 2007, he became ARM's director. His office is at Pacific Northwest National Laboratory (PNNL) in southeastern Washington State. PNNL is one of the nine DOE national labsExternal link that manage and operate ARM.

As the director, he wanted to make a difference. How? He leads the organization that offers the most comprehensive view of the atmosphere to date. He's led the ARM team to deploy instruments in extreme environments that are gathering never-before-seen data on atmospheric processes that touch, in some way, every aspect of life on Earth.

ARM gathers data, including aerosol properties, trace gas levels, microscopic and macroscopic cloud properties, electromagnetic energy, and soil temperature along with other surface properties. How much data? Currently, ARM gathers about 20 terabytes of data in a month. Scientists access the data for free via ARM's Data Discovery websiteExternal link.

To gather atmospheric data, ARM uses close to 400 instruments in an approach best described as a laboratory without walls.

Laboratory without walls

ARM includes three fixed-location observatories, on a tropical island in Portugal, among pastures in Oklahoma, and on the North Slope of Alaska.

Graciosa Island, west of Portugal's mainland, is ARM's newest fixed-location site, known as the Eastern North Atlantic observatoryExternal link. "We see nearly every type of cloud you can imagine," said Mather. Of particular interest are low-level clouds, called marine stratocumulus clouds. The data gathered here in the Atlantic Ocean will help explain changes in the near-surface atmospheric structure and in aerosols.

Located amid cattle pastures and wheat fields of north-central Oklahoma and southern Kansas, ARM's Southern Great Plains siteExternal link is a central observatory and a network of supporting facilities.

The instruments have an unobstructed view of weather systems, from blizzards to tornadoes, that crisscross North America. Mather and his colleagues have overseen changes at this site. Notably, they brought in the instruments necessary to free them from a narrow view, resembling a soda straw, of the atmosphere directly above the site to an expansive, four-dimensional view.

At the top of the world is the North Slope of Alaska siteExternal link. Set on snowy tundra outside Barrow, Alaska, instrument decks and large towers continuously collect data about atmospheric processes that affect global weather patterns and ocean currents.

Observatories and data on the move

Because fixed observatories are by definition stationary, ARM also has mobile observatoriesExternal link and aerial observatoriesExternal link that are deployed from the Amazon to the Antarctic. "Our observatories are out where the interesting weather is," said Mather.

That's often away from urban settings, such as 16,000 feet up a mountain in Chile. But not always. Mobile facilities have gathered data in more urban areas such as Darwin, Australia.

Teams deploy the mobile setups as part of field campaignsExternal link. Scientists, regardless of their nationality or institutional affiliation, can propose field campaigns. The ARM Infrastructure Management Board and the ARM Science Board select a fraction of those proposals to become campaigns. Some campaigns are relatively small, involving a single instrument. Others are quite complex, with multiple agencies, ground sites, ships, and aircraft.

One of the toughest field campaigns was at the bottom of the world. The ARM West Antarctic Radiation ExperimentExternal link delved into the anatomy of polar clouds. The ARM staff turned an unused shed, about a mile down the road from the U.S. McMurdo Station, into a mobile observatory. They packed the tiny building and surrounding snow-covered field with weather-hardened radar systems, radiometers, wind profilers, and more.

The team spent more than a year there collecting data. "In Antarctica, it was hard to get in and out," Mather said. "Scientists had to stay a long time as we couldn't rotate staff like we normally do."

Fingers on the pulse

As the ARM director, Mather faces a challenge unlike his colleagues at other user facilities. The ARM team is distributed across nine national labs, not housed in a single building on a single campus. Communication is even more important among the dispersed teams, which have more autonomy regarding their domains (like operating an observatory or data center) than in other facilities. Thus, Mather spends time gathering information and solving problems across time zones and organizations.

"He has his fingers on the pulse of universities and national labs," said Hanna Goss, ARM's Communications Officer. "He knows ARM into the details."

Mather spends time talking with researchers about how to best facilitate atmospheric measurements to address specific questions, such as refining computer models to better account for clouds. His work often begins by determining the data necessary to answer a question and then figuring out how to best get it. In some cases, that means entirely new capabilities. "We are continually looking ahead to see what new technologies we need," said Mather. "It's pretty exciting to work on the capabilities."

Facilitating measurements isn't just about new capabilities and deployments, although Mather's overseen plenty of both. It also involves modifying or relocating existing instruments. "The ultimate optimal configuration is an incredible technical challenge," said Mather. "It's often tricky to do."

But also fun. Mather truly enjoys helping people answer scientific questions about clouds and their impact.

Over the years, Mather and his colleagues at ARM have provided never-before-captured data to answer tough questions about day-to-day atmospheric conditions that affect us all. ARM gives researchers — worldwide — data they could never have obtained otherwise. "I've gotten to make a difference," Mather said. "And that's always been my goal."

In Fiscal Year 2018, ARM and the other user facilities welcomed 36,217 researchers — from academic, industry, and government laboratories in all 50 states and the District of Columbia — to perform new scientific research. For details on the DOE Office of Science user facilities, go to

Please go to Profiles of User Facilities Directors to read more articles on the directors for the Office of Science user facilities.


The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information please visit

Kristin Manke is a Communications Specialist on detail with the Office of Science, [email protected].