Fujita, Tetsuya Theodore (1920-1998)

Japanese-born American meteorologist

In 1974, Theodore Fujita became the first scientist to identify microburst wind shear, a particularly intense and isolated form of wind shear later blamed for several devastating airline accidents in the 1980s. The development of Doppler radar allowed Fujita to track and explain the microburst phenomenon, which is now far better understood and avoided by aviators. Fujita also lent his name to the "F Scale" he developed to measure the strength of tornadoes by analyzing the damage they cause on the ground.

Fujita was born in Kitakyushu City, Japan, to Tomojiro, a schoolteacher, and Yoshie (Kanesue) Fujita. Fujita showed an early aptitude for science and obtained the equivalent of a bachelor's degree in mechanical engineering from the Meji College of Technology in 1943. It was while he was working as an assistant professor of physics at Meji that U.S. forces dropped the atom bomb on the Japanese cities of Hiroshima and Nagasaki. Fujita visited the ruins three weeks after the bombings. By measuring the scorch marks on bamboo vases in a cemetery in Nagasaki, Fujita was able to show that only one bomb had been dropped. Surveying the damage in Hiroshima, Fujita calculated how high above the ground the bombs had exploded in order to create their unique starburst patterns, which would become important to his later work.

Leaving Meji College in 1949, Fujita became an assistant professor at Kyushu Institute of Technology while pursuing his Ph.D. in atmospheric science at Tokyo University. Like others involved in atmospheric science, he had read the published articles of Horace R. Byers of the University of Chicago, who had conducted groundbreaking research on thunderstorms in 1946 and 1947. Fujita translated two of his own articles on the same subject into English and sent them to Byers. Byers was impressed with Fujita's work and the two men began a correspondence. In 1953, the year Fujita received his doctorate, Byers extended an invitation to the Japanese scientist to work at the University of Chicago as a visiting research associate.

Fujita worked at the University as a senior meteorologist until 1962, when he became an associate professor. For two years beginning in 1961, he was the director of the Mesometeorological Research Project, and in 1964, Fujita became the director of the Satellite and Mesometeorology Research Project. Fujita was made a full professor in 1965, and held the Charles E. Merriam Distinguished Service Professorship on an active basis and on an emeritus basis. He became a naturalized U.S. citizen in 1968, and adopted the first name Theodore for use in the United States. He married Sumiko Yamamo in June, 1969, and has a son from his first marriage.

From the mid–1960s, Fujita and his graduate students did extensive aerial surveys of tornadoes. Fujita claims to have logged over 40,000 miles flying in small planes under the worst of weather conditions. In the late 1960s, Fujita developed his tornado "F Scale." Traditionally, meteorologists listed only the total number of tornadoes that occurred, having no objective way to measure storm strength. Fujita constructed a system of measurement that correlates ground damage to windspeed. His six point system operates on an F–0 to F–5 scale and is similar to the Richter scale used to measure the strength of earthquakes.

Fujita did not actually witness a tornado until June 12, 1982, so the mainstay of his work was research on the aftermath of tornadoes. While at the National Center for Atmospheric Research in Denver, Colorado, Fujita spotted a tornado in the region early and collected some of the best data on the phenomenon ever.

In 1974, Fujita began analyzing the phenomenon of microbursts. Flying over the devastation wrought by a tornado, he noticed patterns of damage similar to those he had witnessed in Hiroshima and Nagasaki. "If something comes down from the sky and hits the ground it will spread out; it will produce the same kind of outburst effect that was in the back of my mind, from 1945 to 1974," Fujita explained in The Weather Book: An Easy to Understand Guide to the U.S.A.'s Weather. Meteorologists knew by the mid–1970s that severe storms produce downdrafts, but they assumed those downdrafts lost most of their force before they hit the ground and, therefore, did not cause much damage, so the phenomenon was largely ignored. Encouraged by Byers, Fujita coined the term "downburst" and began research to prove his thesis that downdraft is a significant weather phenomenon. Aided by the National Center for Atmospheric Research, he set up a project near Chicago that detected 52 downbursts in 42 days.

Fujita was eventually able to show that downdrafts cause so-called wind shear, a sudden and dramatic change in wind velocity, which causes damage on the ground and is a particular hazard in aviation, especially to planes taking off, landing, or flying low. Windspeeds up to F–3 are common for downbursts (higher F Scale readings usually indicate tornadoes). Fujita has commented that a lot of damage attributed to tornadoes in the past has really been the work of downbursts. "After I pointed out the existence of downbursts, the number of tornadoes listed in the United States decreased for a number of years," Fujita noted in The Weather Book.

Fujita's research finally gained national attention in the 1980s. Wind shear caused by downdraft was cited as a contributing factor in the July 1982, crash of a Pan American 727 in New Orleans, Louisiana, which killed 154 people. During that event, the airliner was observed sinking back to the ground shortly after takeoff—the apparent result of wind shear. Another accident occurred in August 1985, when Delta Flight 191 crashed at Dallas-Ft. Worth Airport, killing 133 people. Again, wind shear was suspected to be the immediate cause of the catastrophe.

Air safety has improved dramatically because of Fujita's work, which led to the development of Doppler radar. Doppler radar is so sensitive it actually picks up particles of debris in the air that are as fine as dust. Movements of these particles are tracked to measure shifts in wind velocity. "This is particularly important in being able to detect the precursor events for severe weather," Frank Lepore, public affairs officer for the National Weather Service, told Joan Oleck in an interview. By 1996, the Weather Service and U.S. Air Force together installed 137 Doppler systems, essentially blanketing the continental United States. Harking back to the airline accidents of the 1980s, Lepore noted "a reduction in those incidents today because there is Doppler radar available. By being able to measure the internal velocity of air moving inside a storm system, [aviators] can see rising and falling volumes of air…. They're now getting 20- and 25-minute warning on thesystems that cause tornadoes."

In 1988, Fujita assumed directorship of the Wind Research Lab at the University of Chicago. Among his many awards were the 1989 Medaille de Vermeil from the French National Academy of Air and Science for identifying microbursts; the 1990 Fujiwara Award Medal from the Meteorological Society of Japan for his research on mesometeorology; the 1991 Order of the Sacred Treasure, Gold and Silver Star from the Government of Japan for his tornado and microburst work; and the 1992 Transportation Cultural Award from the Japanese Government for his contributions to air safety. Fujita died in Chicago at the age of 78.