University of Florida, Gainesville
Martin A. Uman was awarded the Fleming Medal at the AGU Fall Meeting Honors Ceremony, which was held on 8 December 2002, in San Francisco, California. The medal is given for original research and technical leadership in geomagnetism, atmospheric electricity, aeronomy, space physics, and related sciences.
“Martin A. Uman is the world’s foremost authority on the physics of lightning, and his contributions in both pure and applied research and in teaching and service have helped to shape progress in the field for almost 40 years.
“Cloud-to-ground lightning produces return strokes, one of the most powerful and damaging processes on Earth, at least at the point of attachment. Martin began his research on lightning in the early 1960s at the University of Arizona, where he analyzed optical spectra of return strokes that had been obtained by Leon Salanave and students such as Richard E. Orville. Martin estimated the peak temperature in a lightning channel, and he made the first estimates of the channel pressure, opacity, and electron density. After a few years, he moved to the Westinghouse Research Laboratories, where he compared the plasma characteristics of lightning with long laboratory sparks and where he wrote two books: one for a popular audience and one technical monograph. Both are still in print. In the early 1970s, Martin moved to the University of Florida, focusing on lightning electromagnetics-work that is his hallmark today.
“While he was at Westinghouse, Martin became interested in the electromagnetic fields that are radiated by lightning. After a short time, he and Kenneth McLain published a new, time-domain theory that described the fields that would be produced by a wave of current that propagated up a long channel at a constant speed. This was an exciting development, because their ‘transmission-line model’ (TLM) predicted a simple relationship between the shape of the radiated field and the current waveform at the ground. Thus, the TLM and a measurement of the field were sufficient to estimate the peak current in a return stroke remotely. After Martin published his model, he and I began a long collaboration in which we measured the characteristics of lightning fields in the time-domain and checked how well the TLM described these fields at various distances. Today, the TLM is being used in many applications worldwide and in research. In 1976, Martin and I co-founded Lightning Location and Protection, Inc. (now Global Atmospheric, Inc.), a small Tucson company that manufactures lightning locating systems and that now owns and operates the U.S. National Lightning Detection Network (NLDN). Today, the NLDN provides real-time lightning data to the National Weather Service and many other agencies, and similar networks are operating in over 40 foreign countries. I can personally attest that Martin’s research provided an excellent foundation for the NLDN and related technology.
“In recent years, Martin has developed new and improved models, and he and Vladimir Rakov have established a large, international laboratory for lightning research and testing near the University of Florida. At this facility, lightning is created artificially using rocket-triggering techniques; and Martin and Vladimir, together with their students and colleagues, are now addressing many questions about the physics of lightning, how lightning interacts with structures, and the mechanisms of lightning damage. They are also using this new knowledge to improve methods of lightning protection and lightning testing.
“In all my associations with Martin Uman, I have found him to be an extraordinary teacher and a scholar of the first rank. He was named Teacher-Scholar of the Year in 1988-1989 at the University of Florida, that university’s highest award for a faculty member, and he was also voted Florida’s Scientist of the Year in 1990 by the Florida Academy of Sciences. AGU has derived much benefit from Martin’s service on committees, his numerous publications, and his insights as a reviewer and an associate editor of the Journal of Geophysical Research. Martin is a Fellow of AGU, AMS, and IEEE, and he received the Hertz Medal from IEEE in 1996.
“On the personal side, Martin is a warm, unselfish individual with a delightful sense of humor. He has helped me and my students at the University of Arizona on numerous occasions, and I am confident that everyone working in atmospheric electricity will be honored by the award of the John Adam Fleming Medal to Martin A. Uman.”
—PHILIP KRIDER, University of Arizona, Tempe
“Thank you very much, Phil. I am particularly pleased that you were able to write my citation. Our long-time collaboration has been a source of considerable pleasure to me, and our joint work has certainly played a significant roll in my being awarded the John Adam Fleming medal.
“The fact that I am in science at all I attribute to an inspiring high school physics teacher, Harry Tropp. My post-Ph.D. career has been strongly influenced by several individuals and several unforeseen events. At the University of Arizona, my primary research in my first faculty position (in the Department of Electrical Engineering) involved the study of weakly ionized gases, an extension of my Ph.D. research. At U.A. in 1962, I serendipitously met the group from the Institute of Atmospheric Physics working on lightning, including my citationist. The subsequent collaboration with this group was to influence the rest of my scientific career, but I didn’t know it at the time.
“At Westinghouse Research Laboratories, my plan was to extend further my dissertation work in Westinghouse’s famous atomic physics group. However, a Boeing 707 exploded after being hit by lightning, and the federal agencies were funding research to understand why. As the laboratory’s only ‘lightning expert’–although I was hardly one then–these circumstances motivated a redirection of my research efforts, and I spent the next 7 years doing little else but studying lightning and long sparks.
“In 1969, Apollo 12 was struck by (actually initiated) lightning (twice) just after launch. More federal money flowed. Phil Krider had received his Ph.D. and was then at NASA in Houston and helped coordinate the lightning community’s lightning/Apollo research effort. Ken McLain (a mathematician at Westinghouse) and I developed some models of return stroke behavior. In order to test those models, Dick Fisher (then an undergraduate at the University of Pittsburgh working part-time at Westinghouse) and I designed the first wide-band lightning electric field measuring system, initially used in Pittsburgh, and then at the Kennedy Space Center in concert with Phil and, after he joined the U.A. faculty, his research group at U.A. At the University of Florida, most of my research in the 1970s and 1980s was done in collaboration with Phil and his team at U.A. As a by-product, Phil and I developed the lightning locating system he describes in the citation. In the early 1990s, Vlad Rakov from Tomsk Polytechnic, Russia, joined the U.F. faculty, providing a quantum leap in the University of Florida’s lightning research capability. In the mid-1990s, Vlad and I founded the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida, where to date, over 35 researchers (excluding U.F. faculty, students, and staff) from 13 countries have studied both natural and triggered lightning.
“Clearly, at each stage of my career, I have been fortunate to have been at the right place at the right time and to be able to work with the right people. Some of those individuals are named above. Others, including then-graduate students Y. T. Lin, Maneck Master, Marcos Rubinstein, and Rajeev Thottappillil, and including colleagues Bill Beasley, Gerhard Diendorfer, Doug Jordan, and C. A. Nucci, have also played a very important role in my career and in my being awarded the Fleming. I thank you all.”
—MARTIN A. UMAN, University of Florida, Gainesville