Panofsky, Hans Arnold

views updated

PANOFSKY, HANS ARNOLD

(b. Kassel, Germany, 18 September 1917; d. San Diego, California, 28 February 1988), aerology, air pollution, atmospheric dynamics, boundary layers, diffusion, planetary atmospheres, similarity theory, turbulence and turbulence spectrum.

Panofsky contributed to a wide range of scientific and engineering disciplines over the span of his illustrious forty-seven-year professional career, including astronomy, planetary and atmospheric sciences, climate, oceanography, air pollution, and most notably, the characteristics, spectrum, and statistical nature of turbulence. A recipient of several distinguishing awards, author of more than 150 papers and several books, supervisor of more than seventy master’s theses and thirty doctoral dissertations, Panofsky contributed a monumental and enduring legacy.

The Early Years In 1916 Dora Mosse married Erwin Panofsky; they had two sons, Hans in 1917 and Wolfgang (“Pief”) two years later. As a scholar of art history, Erwin published his first significant work in 1924 on the history of the Neoplatonic theory of art, and he began to develop his “iconological” approach to art history while at the universities of Berlin, Munich, and Hamburg. When Hans was seventeen years old, the Panofsky family was forced to flee Germany as the Nazis came to power. In 1934 they immigrated to the United States, where Erwin took on joint appointments at New York University and at Princeton. In 1935 Erwin was invited to join the faculty at the Institute for Advanced Study at Princeton University, and there he remained until his death in 1968. As a teenager, Hans found himself immersed in the stimulating intellectual company of some of the most outstanding scientists and humanists of the twentieth century at a time when science and society were in a profound state of flux. The Panofskys’ neighbor, Albert Einstein, would frequently spend leisure time with Hans’s father. Because Erwin did not drive, he would ask Hans to drive them around Princeton while Einstein and the elder Panofsky, speaking German, would converse in the back seat. One can only imagine the rich conversations that Hans was party to during these outings.

Hans earned a BS in astronomy from Princeton in 1938, graduating summa cum laude. He then left for the West Coast to continue his education at the University of California at Berkeley, where he completed his PhD in astronomy in 1941. Along the way, Panofsky gained notoriety for breaking instruments; he would have others operate a telescope while he gathered his data. His first job after completing his PhD took him to Wilson College, a small women’s liberal arts college in Chambersburg, Pennsylvania, as an instructor in mathematics and astronomy. It was there that Panofsky met and married Margaret Ann (Nancy) Riker, also originally from Princeton.

Upon leaving Wilson College, he joined the faculty at New York University where, in addition to his regular assignments, he taught wartime courses in meteorology for the Air Force. It was during the 1940s while at NYU that Panofsky became involved in air quality and boundary layer research and other geophysical subjects such as climate theory, oceanography, and the nature of atmospheric turbulence. His range of interests is exemplified by his published work in the Journal of Meteorology and the Bulletin of the American Meteorological Society between 1944 and 1950, on topics that included computing vertical motion in the atmosphere, pressure systems, vertical velocities and changes in cloudiness, radiative cooling, the significance of meteorological correlation coefficients, objective weather map analysis, a zonal index for Jupiter’s Red Spot, and the stability and meandering of the Gulf Stream.

During this period he held research associate positions at Princeton, Woods Hole Oceanographic Institution, the University of California at Los Angeles (UCLA), and Lowell Observatory. By 1950 Panofsky had developed a reputation as a highly regarded scientist and outstanding teacher at NYU. He continued his ties with Princeton and Brookhaven National Laboratory into the early 1950s, collaborating with John von Neumann at Princeton during the early days of numerical weather prediction (they were among the first to apply computer analysis to weather prediction) and working with the meteorology group at Brookhaven. It was during this time that Hans’s brother Wolfgang became an esteemed professor of physics at Stanford University and director of the Stanford High Energy Physics Laboratory; he was later appointed director of the Stanford Linear Accelerator Center, a position he held from 1961 to 1984.

The Penn State Years: 1951–1982 In 1951 Panofsky left NYU and joined the fledgling meteorology program at Pennsylvania State College as associate professor of meteorology at a time when meteorology was a division of the Department of Earth Sciences under the chairmanship of Hans Neuberger. Panofsky was promoted to the rank of professor in 1953, the same year that the name of the institution was changed to Pennsylvania State University (PSU) under President Milton Eisenhower. HAP, as he signed his name and many affectionately called him, played a key role in strengthening and expanding the meteorological program, and he served as acting head during Neuberger’s sabbatical, at a critical time when the Division of Meteorology became the Department of Meteorology. A 1960 visiting committee to evaluate the department identified Panofsky as the most prolific faculty member (Harry Wexler Papers, Library of Congress).

Panofsky’s scientific contribution to the understanding of the atmospheric boundary layer and the spectrum of turbulence stands at the pinnacle of his lifetime scholarly achievements. Panofsky’s interest in boundary layers and turbulence actually began at NYU with an air quality study sponsored by Consolidated Edison Company of New York. Shortly after moving to PSU, he collaborated with Brookhaven National Laboratory (BNL) to study the diffusion of plumes released from tall towers. From 1958 through 1962, he was prolific in groundbreaking research on turbulence, including the derivation of wind profiles under diabatic conditions, meteorological and aeronautical aspects of atmospheric turbulence, turbulent energy budget, scale analysis of atmospheric turbulence, and the effects of wind loads on structures. Many of these topics were new areas of study at the time, and Panofsky led the way with insight and enthusiasm. In the early twenty-first century scientists continued to expand on his early work to better understand the conditions that lead to turbulence under varying atmospheric conditions.

In 1960 Panofsky was named a John Simon Guggenheim Memorial Fellow, and he spent a year at Cambridge University to study the basic theory of turbulence under G. K. Batchelor, publishing two short papers. It was during this period that Panofsky invited John Lumley to join him in writing the milestone monograph The Structure of Atmospheric Turbulence (1964). Panofsky’s interest in Monin-Obukhov similarity theory (to use a set of non-dimensional parameters to describe surface later fluxes), Kolmogorov scaling (to describe the smallest scales of turbulences), and the spectrum of turbulence (describes the relationship between the energy of a turbulent eddy and the eddy size (wavelength or wave number) is evident in the monograph, and served as the impetus for his research efforts for the rest of his career.

Panofsky’s boundless curiosity sustained his multifaceted interests across a range of subjects throughout this period, as demonstrated by his publications on TIROS measurements of tropospheric conditions, estimates of stratospheric flow from satellite 15-micron radiation, relationships between synoptic variables and satellite radiation data, and climate. Panofsky was at the forefront of a growing number of scientists whose research sparked concern about threats to the ozone layer; this at a time when CFCs in spray cans were being banned by Oregon (1975) and by the United States (1978), and the United States was considering building a fleet of stratospheric commercial jetliners, and seven years before British investigators discovered the “ozone hole.” This led to his appointment to a National Academy of Sciences (NAS) committee to evaluate the Department of Transportation’s Climatic Impact Assessment Program. The committee focused on the ramification of large-scale use of the supersonic transport (SST) on stratospheric ozone, and went on to show that “while high-level flights can diminish ozone concentrations, their impact is felt to be small in comparison to the problems these flights create in the form of sonic booms and high costs” (NAS, 1975).

In addition, Panofsky coauthored publications with his students and colleagues on mesoscale variations and phenomena, radiation fluxes, and large-scale vertical motion. In 1965 he received the American Meteorological Society’s Clarence Leroy Meisinger Award in recognition of his research achievements in aerology and atmospheric motions on all scales. Panofsky spent the spring of 1966 as visiting professor at the University of Washington. Upon his return, university president Eric Walker appointed him the Evan Pugh Professor of Atmospheric Science on 1 July 1966, the highest distinction PSU bestows on a faculty member.

Panofsky’s interest in turbulence in the free atmosphere above the planetary boundary layer developed in conjunction with the ability of aircraft to reach greater altitudes. Clear air turbulence (CAT) became a hazard to be reckoned with, and Panofsky focused his interest in upper tropospheric and stratospheric dynamics and turbulence to address the problem, publishing with coauthors two manuscripts on CAT: the first on case studies of the distribution of CAT in 1968, and the second in 1976 on temperature gradients and CAT probabilities. His work continued through the 1970s on surface similarity, scale analysis of atmospheric turbulence, spectra and co-spectra of turbulence, heat and momentum fluxes, and spectral gaps, and led to significant progress in the areas of boundary layers, turbulence, and the meteorology of air pollution events. Instrumented towers provided him with the necessary measurements to characterize turbulence under a variety of stability conditions and to assess the integrity of structures to wind loading, a topic that had sparked his interest since his early work with BNL.

In addition to the Lumley-Panofsky monograph on The Structure of Atmospheric Turbulence(1964), Panofsky published An Introduction to Dynamic Meteorology in 1956, Some Applications of Statistics to Meteorology with Glenn Briar in 1958, and a general undergraduate textbook, The Atmosphere, with Richard A. Anthes, John J. Cahir, and Albert Rango in 1975.

The Panofsky Legacy The atmospheric sciences community was not remiss in acknowledging Panofsky’s contributions. Most notably, in 1976 Panofsky received the American Meteorological Society’s Carl-Gustaf Rossby Research Medal “for his many fundamental contributions to the understanding of turbulent processes and the links between small-scale and large-scale dynamics in the atmosphere.” The Rossby Medal represents the highest honor that the Society can bestow upon an atmospheric scientist, and Panofsky described the receipt of this medal as “the culmination of my career.” In addition, he was a Fellow of the American Meteorological Society, American Geophysical Union, and the American Association for the Advancement of Science, for which he served as chairman for the Atmospheric and Hydrological Sciences. He held memberships in the Royal Meteorological Society, Sigma Xi, and Phi Beta Kappa.

For all the fundamental contributions that Panofsky made to the subjects of atmospheric turbulence, satellite meteorology, planetary atmospheres, and climate, it was his students, colleagues, and friends that meant the most to him, according to Alfred Blackadar. In later years, when asked to describe his career, Panfosky said, “My principal interest as a university professor has always been teaching, at all levels. It is a great pleasure to share one’s limited knowledge and understanding with students, and occasionally see them develop an enthusiasm for the subject” (http://www.met.psu.edu/dept/aboutus/his.html#recollections). Threading through the testimonies of former students and colleagues in a dedication to Panofsky by John Wyngaard in Boundary Layer Meteorology (1989) are attributes such as generosity, modesty, warmth, humility, enthusiasm, curiosity, and boundless imagination. Many of his contemporary professional associates have come to be considered some of the most influential leaders in the atmospheric sciences, and many of his students have occupied key positions in universities, national laboratories and agencies, and private enterprises.

Panofsky retired from PSU in 1982 but remained actively involved in research and publication. In 1983 he was named the Erskine Fellow at the University of Canterbury in Christchurch, New Zealand. The same year he published an article with coauthors on a refinement to an explicit eddy exchange coefficient formulation while at Colorado State University as a visiting professor, and the following year he took a position as research associate at the Scripps Institution of Oceanography. Still trying to shape the thinking of generations of students, in 1984, two years after his retirement, Panofsky and John Dutton produced a text, Atmospheric Turbulence: Models and Methods for Engineering Applications, that continued to serve as a valuable reference in the early twenty-first century. Also in 1984, Panofsky was honored by his undergraduate alma mater when Princeton University presented him with the Class of 1938 Distinguished Service Award.

Panofsky’s insatiable curiosity never waned. John Dutton, Dean Emeritus, College of Earth and Mineral Sciences at PSU, recalls last seeing HAP in March 1986, age sixty-eight, at the American Meteorological Society Short Course of Air Pollution Modeling in San Diego, “enrolled as a student, taking a front-row seat and keeping the lecturer alert.” His youthful inquisitiveness remained a hallmark of his character until his death in 1988. Alfred Blackadar, professor emeritus of Meteorology at PSU, described Panofsky as a “brilliant mind, interested in everything, and unfailingly observant,” and his research across the broad panorama of geophysical and atmospheric sciences bears this out.

While Panofsky’s contributions are many and varied, he is most likely to be remembered for his work on the spectrum of turbulence. His publications on clear-air turbulence, diabatic wind profiles, scale analysis of turbulence, spectra and co-spectra of atmospheric turbulence, similarity theory, and the turbulent energy budget were mileposts in a fledgling discipline into which a generation of students would venture.

BIBLIOGRAPHY

See the Pennsylvania State University Special Archives on Hans

A. Panofsky. Reminiscences are available from http://www.met.psu.edu/dept/aboutus/his.html#recollections.

WORKS BY PANOFSKY

An Introduction to Dynamic Meteorology. University Park: Pennsylvania State University Press, 1956.

With G. Briar. Some Applications of Statistics to Meteorology. University Park: Pennsylvania State University Press, 1958.

With Alfred K. Blackadar and G. E. McVehil. “The Diabatic Wind Profile.” Quarterly Journal of the Royal Meteorological Society 86 (January 1960): 390–398.

“The Budget of Turbulent Energy in the Lowest 100 Meters.” Journal of Geophysical Research 67 (July 1962): 3161–3165.

With John L. Lumley. The Structure of Atmospheric Turbulence, Monographs and Texts in Physics and Astronomy. Vol. XII. New York: Wiley and Sons, 1964.

“Analyzing Atmospheric Behavior.” Physics Today 23 (December 1970): 32–35.

With John A. Dutton. “Clear Air Turbulence.” The Physics Teacher 8 (December 1970): 489–498.

With Richard Anthes, John J. Cahir, and Albert Rango. The Atmosphere. Columbus, OH: Charles E. Merrill, 1975.

With John A. Dutton. Atmospheric Turbulence: Models and Methods for Engineering Applications. New York: Wiley and Sons, 1984.