Electromagnetic Research in Antarctica

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During the 1960s and 70s, a group of UW faculty members and graduate students carried out an extensive program of research to study radio wave propagation in the Antarctic ionosphere and terrain. As a part of that effort, electrical engineering professor Irene Peden and colleagues obtained the first quantitative information about the electromagnetic properties of the Antarctic ice sheet, data critical to communications and navigation in the south polar region. In so doing, Peden became the first woman to conduct research in the Antarctic interior.

The ionosphere is a region high in the atmosphere, beginning at 70-80 km and extending up thousands of kilometers--a region rich in free electrons and ions produced by solar radiation. In general, low-frequency radio waves can be reflected off this layer from below, and phenomena occurring within the layer may affect radio communications markedly.

Radio waves also can be reflected from the ground or the surface of the ocean. In the Antarctic, they are reflected from the ice sheet that covers the continent, and from the rock below. Thus, the ionosphere and the ice/rock layer together create the upper and lower boundaries of a waveguide--a sort of air-filled "sandwich." Inside the waveguide, radio waves bounce back and forth and can be propagated over long distances.

In order to study aspects of this sort of radio propagation, electrical engineering professors H. Myron Swarm and Donald K. Reynolds had initiated a program of Antarctic research in the early 1960s. "The first research project was the construction and testing of a 21-mile dipole antenna on the surface of the Antarctic continent near Byrd Station (address 80° S latitude, 120° W longitude)," recalls Ward J. Helms of the electrical engineering department. "The initial investigator was Arthur W. Guy," a graduate student, who, together with two other graduate students, installed and measured the impedance of the antenna. That marked the beginning of a long and distinguished career in the field of electromagnetic research for Guy, now professor emeritus in the UW bioengineering department.

In later years of the UW Antarctic program, participating professors took turns going to the Antarctic to supervise the research, while graduate students remained at the site to carry on the work for continuous periods through the coldest portion of the season.footnote 1 Applications of the antenna were pursued by various researchers in the department, including Helms, H. R. Willard, and Guy, in addition to Swarm, Reynolds, and Peden.

In 1966, two long-term applications of the 21-mile dipole were started. They were the D-Region Sounder by Helms and a Man Made Whistler Mode Transmission Project by Willard. Helms assisted in the construction of the "Longwire" substation about 5 miles west of Byrd Station. He installed a special radar transmitter that was used in a measurement of energetic particles falling into the atmosphere from space.

With support from the Office of Polar Programs at the National Science Foundation (NSF), Peden and her research students conducted theoretical studies and developed new methods for measuring the electromagnetic properties of the Antarctic ice sheet and of the physically inaccessible underlying terrain. They characterized the complete VLF (Very Low Frequency, 3-30 KHz) fields within these regions created by the horizontal antenna, for both summer and winter conditions.

"This work provided the first quantitative information available to the polar ionospheric and glaciology communities about the bulk average electromagnetic parameters of the ice sheet and underlying rock in the vicinity of Byrd Station as a function of frequency in the 3-30 KHz band," she recalls.

Later, Peden and her students made use of the first deep drill hole to the bottom of the ice sheet at Byrd Stationa 6-inch diameter, 2,164-meter "laboratory"to measure the electromagnetic parameters as a function of vertical depth and temperature.

During the 1980s and 90s, Peden applied her expertise to another important problem: developing methods for remote sensing and detection of subsurface objects such as buried pipes or tunnels. To do this, she used Very High Frequency (VHF) ground-penetrating radar from 30 to 300 MHz in a cross-borehole sensing configuration, which provides the best potential for detection, location, and reconstruction of subsurface geophysical images. As a member of the U.S. Army's tunnel detection panel of experts, she served as test evaluator for the Pulsed Electromagnetic Sensor System in an application which involved searching for tunnels under the Demilitarized Zone in Korea. The approach has many potential commercial and military applications.

Peden's research accomplishments are matched by her personal triumphs as the first woman to conduct research in the Antarctic interior. During the 1960s, it was NSF policy that principal investigators of Antarctic research projects should spend time on-site in order to gain a direct understanding of the region and of the extreme difficulties confronting polar experimental work.

Peden, then a 45-year old associate professor, had worked on the Antarctic grant for several years already and she was long overdue to make the trip; but no women had ever worked there and the Navy was adamant she shouldn't go. Women hadn't even been permitted to do research on the Antarctic coast at that time, let alone in the interior. She had to wait until after a team of four women geochemists from "one of the Big Ten schools" went to the coast in the summer of 1969 in order to get permission to make her trip to the interior. In 1970, it was finally her turn.

The Navy, which controlled transportation to the site, kept dragging its feet, she recalls. One of the admirals was dead set against it. Peden had to make a special proposal and presentation to justify her trip, going to lengths far beyond those required of her male counterparts. Then, the Navy insisted that in order to go, she must have a female traveling companion, a requirement which created further delays. Finally, Peden arrived at McMurdo station in Antarctica in late October.

In order to carry out research in the Antarctic interior, scientists had to battle numbing cold, spartan accommodations, risky weather conditions, extreme isolation, long hours, and a monotonous diet of canned, frozen, and dried food, among many other hardships. But in addition to those, Peden faced an even more serious obstacle. Some boxes of the most crucial equipment needed to carry out her project were never delivered. The pressure was intense: the NSF station chief in McMurdo was radioing to her that the work must be completed on time, and if not, there wouldn't be another woman on the Antarctic continent for a generation. Peden and the station staff managed to improvise a substitute. Working a grueling schedule to make up for lost time, the researchers succeeded in obtaining the needed data. The experiment was a success, and served to open the doors for women in science and engineering research in Antarctica for generations to come.

In 1993, Peden was elected to the prestigious National Academy of Engineering with a distinguished record of technical firsts to her name. And there's a rock in the Antarctic ("named Peden-something-or-other," she says) that stands as a small monument to a great triumph for science and for women.

  1. We thank Daniel Dow, Ward Helms, Rubens Sigelman, Irene Peden, and Mark Damborg for information and assistance they provided in the preparation of this vignette.

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