Another Summer Spent Shooting Rockets, Flying Balloons, and Studying Lightning, Sept. 15, 2008

Or, what did you do on your summer vacation, professor?

By Thomas Guengerich

SOCORRO – A small group of the nation’s preeminent atmospheric physicists are wrapping up their summer’s field research into lightning, clouds, electricity, x-rays and ozone atop South Baldy Mountain about 50 miles southwest of Socorro.

For more than 50 years, New Mexico Tech has operated Langmuir Laboratory, the nation’s first facility dedicated to the study of lightning and the atmosphere. Tech professors and students have been joined this summer by scientists, researchers and volunteers from Stanford, the National Severe Storm Laboratory and industry groups to collaborate on a wide range of atmospheric research.

Dr. William Winn

William Winn (right), director of Langmuir Laboratory since the 1980s, said researchers at Langmuir Lab have made ground-breaking discoveries ever since the facility opened in the 1960s. Tech professors have pioneered technological advances that allow scientists to image lightning in clouds, examine where lightning begins and ends and study the distance lightning can travel, Winn said.

Studies of electricity have also lead to new understandings of the dynamics of electrical charges in thunderclouds and how lightning redistributes those charges, he said.

“This is an exciting field of research,” Tech vice president Van Romero said. “There are other laboratories that study lightning, but none have the unique mountain features and the longevity that Langmuir Lab offers.”

Romero, who earned two degrees in physics from New Mexico Tech, said university scientists and visiting researchers use Langmuir to conduct cutting-edge research that supports efforts to minimize lightning exposure at NASA and within the aviation community.

One method of gathering lightning data is launching specialized instruments into thunderstorms that pass over the mountaintop lab. The teams use weather balloons to launch as many as seven instruments at a time – all of which are equipped with GPS locators and measure different aspects of the atmosphere. Each instrument is called a “sonde,” which is a device sent skyward to record various aspects of the atmosphere.

Another method for gathering lightning data involves a ground-based array of radio receivers. Over the past 30 years, Tech professors Bill Rison, Ron Thomas and Paul Krehbiel pioneered the Lightning Mapping Array, a system of multiple radiowave sensors that can create a three-dimensional image of lightning in nearly real-time. The mapping array is an integral tool for future research of lightning.

“The fun part is playing with gadgets,” New Mexico Tech physics professor Ken Minschwaner said. “The challenge is having these gadgets work when we need them to work. We have very small windows of opportunity to launch an instrument into a thunderstorm. When it all works, it’s quite a satisfying feeling.”

Dr. Doug Kennedy

Right: Doug Kennedy of the National Severe Storm Laboratory prepares to launch a test balloon on a recent stormy afternoon. Scientists launch a test balloon to visually check the prevailing winds prior to launching instruments into a storm.

Three researchers from the National Severe Storm Laboratory in Norman, Okla., spent three weeks at Langmuir studying the electrical fields in lightning storms and collaborating with Tech researchers on their ozone research.

Two Stanford University researchers spent nights at the laboratory studying elves and sprites – lightning that emanates upward from a thundercloud.

Tech physics professors have several different projects ongoing at the mountaintop facility.

Dr. Ken Minschwaner

Dr. Ken Minschwaner (kneeling) attaches his ozone sonde to a weather balloon during summer experiments. His instrument was one of seven attached to the balloon on that day. In the background are Doug Kennedy and Sherman Frederickson (right) of the National Severe Storm Laboratory in Tulsa, Okla.

Professor Ken Minschwaner just completed his third year of studying ozone created by lightning. The National Severe Storm Laboratory researchers came specifically to collaborate with the ozone experiments. Their instrument (initially developed in the 1970’s at New Mexico Tech) measures electric field strength.

“We want to find out if ozone is produced in regions where the electric field is strong,” Winn said. “We also want to find out if ozone is produced by lightning; thus the Lightning Mapping Array is also an essential part of the ozone experiment.”

Professor Ken Eack has two projects this summer. He is studying the relationship of X-rays and lightning, an emphasis of his research for more than six years. Also, he and Winn have developed the next generation of commandable “controlled cut-down” device, which will allow researchers to remotely disconnect the instruments from the balloon. In theory, that device will allow researchers more control over the landing spot of their instruments, making retrieval easier.

Physics professor and lightning researcher Richard Sonnenfeld said thunderstorm X-rays are a puzzle in atmospheric studies.

“The existence of hard X-rays around lighting flashes is a real mystery because ordinary electrical breakdown processes only require electron energies that are very much smaller than X-ray energies,” Sonnenfeld said. “If X-rays are associated with lightning at the initiation point, it suggests that at least some lightning flashes are started by unusual breakdown processes, perhaps initiated by cosmic rays.”

If Dr. Eack succeeds in making the connection between cosmic rays and terrestrial lightning, it would be a very beautiful result in the unification of the cosmos with our earth-bound experience, Sonnenfeld said.

The mapping array plays an essential role in measuring the relative locations of lightning and X-rays, Sonnenfeld said. In future experiments, the electrical field sonde, which measures rapid changes in electric field during lightning flashes, will be flown with an X-ray detector to give additional information.

For the researchers at Langmuir Lab, summer time is like a festival of high-tech gadgets. The level of activity fluctuates from very low activity – waiting for a storm, tinkering with sondes and preparing balloons – to intense activity – firing rockets, launching balloons and ducking for cover. Adjacent to the balloon hangar, the crew spends time assembling their sondes, double-checking and triple-checking their equipment and monitoring the atmosphere. A computer screen constantly displays a radar image of the weather.

About a half-mile from the balloon hangar, the lab manages a rocket launch pad. From a secure position underground, a technician can launch an elaborate model rocket that drags hundreds of feet of copper wire into a thunderstorm. The rocket and its metal attachments trigger lightning, which follows the path of least resistance to the ground – the copper wire.

Safety is a great concern at the lab. Lightning claims more victims each year than snowstorms, hurricanes and tornadoes. According to the National Weather Service, lightning strikes cause an average of 73 deaths each year and hundreds more debilitating injuries. Winn said research at Langmuir Lab provides important insights into this deadly phenomenon. Researchers spend days or weeks preparing for one balloon flight, then spend literally years examining and interpreting the data.

Ken Minschwaner

Dr. Ken Minschwaner, Tech physics professor, explains his ozone sonde, which is a chemistry experiment attached to a motherboard with a GPS device.

All atmospheric research is interdisciplinary. Minschwaner’s flying sensor – or “sonde” – is basically a chemistry kit attached to a small motherboard, with a transmitter and a GPS device. He visited the Tech chemistry department to mix the base chemicals for his flying sonde. He also had to write computer code to decipher the data. He’ll then use higher-order physics to analyze the data and make hypotheses about naturally-created ozone.

To a layman, physics might seem like an academic pursuit, but to the Langmuir Lab researchers, studying the atmosphere is a hands-on activity. Minschwaner said that in the classroom, he stresses the importance of instrumentation and experimentation equally as much as analysis and interpretation.

“It’s important that we not only teach them about science and math, but also the fun stuff that goes along with it,” he said.

– NMT –