Modeler and observationalist Adam Varble tells how he got into atmospheric science by falling in love with storms

Adam Varble, Pacific Northwest National Laboratory, will lead the U.S. Department of Energy (DOE) ARM user facility campaign called Cloud, Aerosol, and Complex Terrain Interactions (CACTI), which begins in October.
Adam Varble, Pacific Northwest National Laboratory, will lead the U.S. Department of Energy (DOE) ARM user facility campaign called Cloud, Aerosol, and Complex Terrain Interactions (CACTI), which begins in October.

“I consider myself a weather weenie,” says Adam Varble.

He is an atmospheric scientist at Pacific Northwest National Laboratory in Richland, Washington, on the arid eastern side of the Cascade Mountains. Every day, he takes time out from his busy days as a modeler and observationalist to scout through local weather measurements.

Outside, when he looks at clouds, Varble calculates how they formed, how they will grow, and even how cold the cloud tops are getting.

As a boy in suburban Milwaukee, Wisconsin, he was an eager watcher of The Weather Channel. “I could see—‘Oh, there’s going to be something interesting tonight,’ then I would stay up and watch it,” says Varble.

One night, a freak storm packing 110 mph straight-line winds took out trees in his hometown of Franklin. The next day the whole neighborhood turned out to cut up broken branches.

Low-lying Franklin had regular floods, too. After a good rain, Varble would head to the backyard with his father with buckets for bailing. “I thought that was great,” he says, and he felt the same about heavy weather in general. “It was the drama of it all.”

To this day, severe weather still captivates Varble, who earned his PhD in 2013 from the University of Utah. It was there that his main mentor, Edward Zipser, established in a landmark 2006 paper that the tallest, largest, and potentially strongest thunderstorms in the world occurred in northern Argentina, east of the Andean cordillera.

Such storms can be 20 kilometers (12.5 miles) high, with cloud shields thousands of kilometers wide.

CACTI Kicks In

Varble will follow the drama (and science) of such storms beginning in October as principal investigator of a U.S. Department of Energy (DOE) field campaign called Cloud, Aerosol, and Complex Terrain Interactions (CACTI).

The idea is to learn more about the life cycle of convective clouds—how they form, grow, organize, and transform into storms of different sizes and intensities.

Storms like this contribute most of the rainfall in many regions of the world. To date, however, a fined-tuned sense of how they work remains absent, which results in poor representations of them in earth systems models.

Varble, left, and Stephen Nesbitt of the University of Illinois, right, pause in 2016 during a site survey in Argentina’s Sierras de Córdoba mountain range for the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign. Photo courtesy of Nesbitt.
Varble, left, and Stephen Nesbitt of the University of Illinois, right, pause in 2016 during a site survey in Argentina’s Sierras de Córdoba mountain range for the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign. Photo courtesy of Nesbitt.

CACTI will unfold from October 2018 through April 2019, with an international team of scientists (as many as 150) gathering where Argentina’s biggest storms are born: the Sierras de Córdoba mountain range in north-central Argentina.

Flash Cards, Physics, and Engineering

Varble was a kid when he took part in his first after-storm backyard bucket brigade with his father. Between that moment and confronting the prickly science problems of CACTI, a few things happened to steer him to the path he is on today.

To begin with, Varble grew up in a household where science, math, and engineering were dominant interests. (His father is an engineer who designs big cranes. His mother back then was a technical draftsman.)

Besides cool storms to marvel at, he remembers sessions with math flash cards as a child, and the years of public school in Franklin, where the teachers thought problem-solving and critical thinking were the order of the day.

In high school, physics stood out. “It came naturally,” he said of the discipline that seemed to “organize the world. At the same time, I was interested in all things science, and still am.”

Along the way Varble realized that the world beyond high school included weather researchers. However, at the University of Wisconsin, Madison (Bachelor of Science 2007), he majored in nuclear engineering for the first three years, and also took courses in civil and mechanical engineering.

By his junior year Varble was frustrated that problem sets in nuclear engineering never seemed to get definitively solved—and that “all the science you did was on things you didn’t see,” he says.

Everyone can see the weather, however, and Varble switched majors to atmospheric sciences. “I was good at this, but not passionate,” he says of nuclear engineering and his decision to leave it behind.

The switch cost Varble a fifth year as an undergraduate but brought him back to his boyhood fascination with the weather.

When he started doctoral studies at the University of Utah, “I was still interested in storms. That’s what drew me to Ed,” Varble says of his mentor, Edward Zipser, who was also “passionate about getting his students out into the field (for campaigns). It does give you perspective.”

Chasing Storm Science

Zipser’s passion for getting out into the field captivated Varble immediately.

In Utah he had also discovered hiking, climbing, and other outdoor pursuits—partly through meeting his now longtime girlfriend, Annie, a Utah native “who grew up camping,” he says.

Spending time outdoors “helps generate interesting science questions,” he says, especially in the intermountain west, where complicated cloud processes are created by steep terrain. “I would look at clouds, observing how they form and how they were changing.”

Storms gather in the distance at Southern Great Plains atmospheric observatory during the Midlatitude Continental Convective Clouds (MC3E) campaign, where Varble (still a graduate student) served as a weather forecaster. Photo courtesy of Varble.
Storms gather in the distance at Southern Great Plains atmospheric observatory during the Midlatitude Continental Convective Clouds (MC3E) campaign, where Varble (still a graduate student) served as a weather forecaster. Photo courtesy of Varble.

Right away, field campaigns were also part of the graduate-school picture.

Varble was a graduate student when he wrote a proposal with Zipser to study data from the 2011 Midlatitude Continental Convective Clouds (MC3E) field campaign at the Southern Great Plains (SGP) atmospheric observatory, part of the Atmospheric Radiation Measurement (ARM) user facility funded by the U.S. Department of Energy (DOE).

He served MC3E as a forecaster—“a great one,” he says. “We nailed all those storms.”

Just a few months earlier, Varble was a volunteer during the 2010-2011 Storm Peak Lab Cloud Property Validation Experiment (STORMVEX). The DOE-ARM field campaign in snow-bound Steamboat Springs, Colorado, emplaced a suite of instruments to study wintertime cloud properties.

“It was amazing,” says Varble of STORMVEX: not only the science, but the heavy snow (more 400 inches that season), the intense cold (routine wind chills of 30 degrees below zero), and the sheer outdoor challenge. “To some people it would be painful, but to me it was a thrill. You don’t forget something like this.”

His PhD dissertation used data from the 2006 ARM field campaign Tropical Warm Pool-International Cloud Experiment (TWP-ICE) near Darwin, Australia, an international effort that focused on airborne measurements of tropical cirrus clouds and the monsoon convective forces that form them.

Varble’s dissertation focused on evaluating cloud models, simulating convective systems and comparing them to observations from TWP-ICE.

It was his introduction, in a way, to what he calls himself now: “a rare hybrid” of modeler and observationalist—a two-bladed approach that one older colleague only half-jokingly told him was “the valley of death” in atmospheric sciences.

To Darwin and Beyond

So far, the valley of death seems just the right thing for the cheerful Varble, who is energetically preparing for CACTI and eager to get out in the field again.

He is busy in the committee room too as co-lead of the Convective Processes Working Group for DOE’s Atmospheric System Research program (ASR) and as a member of DOE’s ARM/ASR Coordination Team.

Varble’s post-PhD years at the University of Utah were devoted to writing research proposals and advising graduate students, two of whom will join him in Argentina. He is also associate editor of Monthly Weather Review and is a regular reviewer for more than 10 journals and research programs.

In the field, a recent departure from his computer monitors took him back to monsoon systems near Darwin, Australia, again—this time in person.

The occasion was the 2014 High Altitude Ice Crystals (HAIC)/High Ice Water Content (HIWC) flight campaign. The international effort focused on measuring and analyzing regions of high ice crystal concentrations to improve airline safety. Funders included Airbus, Boeing, the National Aeronautics and Space Administration, the Federal Aviation Administration, and the European Aviation Safety Agency.

“I love going on field campaigns,” he says. The next and biggest in his career so far is CACTI, an effort to unlock the mysteries of how Argentina’s sometimes extremely large and tall storms are made.

The science of it all is amazing, you could say of CACTI. As Varble might say, so is the drama of it all.

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This work was supported by the U.S. Department of Energy's Office of Science, Office of Biological and Environmental Research as part of the Atmospheric System Research Program.