PALMéN, ERIK HERBERT

(b. Vaasa, Russia [Finland], 31 August 1898; d. Helsinki, Finland, 19 March 1985), synoptic and dynamic meteorology, aerology, oceanography.

Palmén’s major contributions to meteorology were studies of the hemispheric character of the jet stream, the existence of a separate subtropical jet stream and the necessary condition for the formation of tropical cyclones. His scientific breakthrough came when he was approaching his fifties and had left his country with the intention of possibly staying away.

Education The son of a judge, Eskil Herbert Palmén, and Sally Maria Skog, Palmén grew up in an intellectual setting and went to the University of Helsinki, where he studied astronomy and was awarded a master of science degree in 1921. The mathematical formalism of celestial mechanics bored him, so he turned to meteorology, in which he had been interested since childhood.

At this time there was, as yet, no academic faculty for meteorology in Finland, so Palmén had to earn his living at the Institute for Marine Research, while, in his spare time, he studied meteorology and lectured in geophysics at the University of Helsinki. During his time at the Marine Institute, which lasted until 1946, he came to acquire a deep knowledge of problems related to the interaction between the atmosphere and the sea. Notable among his oceanographic works are the determination of interactions between wind stress and water-level changes and stratification, an explanation of the equatorial countercurrent, and analysis of the momentum balance of the Antarctic circumpolar current. But it was in meteorology that Palmén would make his greatest contributions, based on his oceanographic work and his independent education, which made him as a meteorologist “a self-made man” (Holopainen, 1985).

Early Meteorological Work Erik Palmén’s scientific career coincided with the era during which theory and observations were increasingly brought together in a coherent conception of the global atmosphere. In the 1920s Scandinavian meteorologists working for Professor Vilhelm Bjerknes in Bergen, Norway (“the Bergen School”) explored new ideas about the general circulation of the atmosphere, in particular with respect to storm developments. The new ideas were introduced to Palmén by one of its leading teachers, Tor Bergeron, who visited Finland in 1922. Palmén’s interest in the new theory is apparent in his 1926 doctoral dissertation on the movement of extratropical cyclones. In 1928 Palmén made a three-month journey in Europe to meet leading meteorologists. After a one month’s stay at the Geophysical Institute in Bergen he began a long working association with Jacob Bjerknes on the three-dimensional structure of atmospheric disturbances.

While the new cyclone theories were received with enthusiasm in the Soviet Union, and with a positive curiosity by the Anglo American meteorological world, the attitude of the Austrian-German meteorologists was hostile. In opposition to the Bergen School they stressed the importance of the redistribution of air of different densities in the upper atmospheric layers, in particular the stratosphere, for controlling lower-level pressure changes. The debate was at first forwarded by theoretical arguments, because observations from the upper atmosphere by kites, airplanes, and balloonborne self-reregistering meteographs were sparse and infrequent.

Together with Jacob Bjerknes, Palmén championed the Bergen School notion that storms developed in the troposphere, in particular in the border zones (frontal zones) of major air masses of different densities. It was true that the Bergen School at first had little to say about the role of the higher atmospheric layers. However, during the midand late 1930s they organized or took part in several coordinated releases by means of the serial release of balloons equipped with registering instruments, which resulted in the first comprehensive aerological analyses over an entire extratropical cyclone (J. Bjerknes and Palmén, 1937). In many of these pioneer studies Palmén showed his intuitive ability to distinguish important aspects of problems from minor ones and to derive from a small amount of data results that later research, based on a much larger body of data, has shown to be essentially correct.

While the Bergen School extended their perspective upward in the troposphere, the German school began to move downward, gradually appreciating the role of the troposphere. A consensus that the main “steering level” of atmospheric motion was in the middle troposphere had to wait until after World War II.

The War Years At the outbreak of the war Palmén became director of the Marine Research Institute after the previous director, Rolf Witting, had become a leading member of the Finnish government. The war and administrative obligations limited any scientific productivity but Palmén found time to help his Swedish colleague and student Alf Nyberg to construct three-dimensional images of the atmosphere based on aerological material collected during two experiments in 1935 and 1939.

The war over and approaching his fifties one would have expected that Palmén would have passed his zenith of scientific achievements. Instead he left Finland with his family in June 1946 for the United States, for a period that turned out to be the most fruitful of his scientific life. In his pocket he carried an immigration visa; he arrived in the New World with the intention of possibly staying there.

Most of his life Palmén had difficulty getting a meteorology position in Finland. The 1930s was a time of political tension in Finland. The small Swedish-speaking minority was regarded by ultranationalistic Finns as alien subjects, reminiscent of a colonial upper class. Though the Swedish minority socially did not differ significantly from their Finnish compatriots, this could not be said about Erik Palmén, who indeed was a baron (Swedish friherre). In 1931, Palmén was refused permission to apply for the post as director of the Meteorological Institute on the grounds that he had not passed a formal test in Finnish.

During the “Finnish Winter War” (1939–1940) the Finnish military was not content with the weather forecasts. They insisted that, in spite of his lack of formal linguistic qualifications, Palmén should replace the head of the forecast office as soon as the ice service work at the marine institute permitted. Before the ice season was over the war ended, in March 1940.

There was another, less political reason why Palmén could not easily make an academic career in Finland. At this time this relatively small country housed another of the world’s leading meteorologists, Vilho Väisälä, the creator of the well-known high-quality radiosondes. Neither Väisälä nor Palmén held a chair at Helsinki University, but were both given the title of professor in 1940. When the existing professor retired in 1943 the chair was left vacant since the university could not choose between the two.

Palmén’s departure was partly a reaction to his difficulty in being recognized as a scientific meteorologist in his home country, and partly because of promising perspectives offered by the Swedish American Carl-Gustaf Rossby, the leading meteorologist at the time. Palmén had met Rossby, then professor at the Massachusetts Institute of Technology, in 1930 on a visit to Bergen. They immediately struck up a lasting friendship sharing common scientific interests, the same (Swedish) mother tongue, a taste for the good things in life, and a nonbureaucratic attitude to work.

Already in February 1941 Rossby had tried to bring Palmén to Chicago as assistant professor in the newly organized Department of Meteorology at the University of Chicago. The wartime conditions had prevented that, but now Palmén accepted Rossby’s renewed invitation and with his family crossed the Atlantic in a weeklong journey in June 1946. Within a couple of years Palmén would make several important contributions to dynamic meteorology which made his name famous in the meteorological world.

Palmén and the “Chicago School.” World War II had established a huge increase in the meteorological observational network, in particular of the upper atmosphere. To investigate the atmosphere’s general circulation from this extensive network Rossby had organized a project with a large group of young American and foreign meteorologists. As the deputy leader of the project he chose Erik Palmén.

Erik Palmén’s scientific contributions in this “Chicago School” project, like almost all of his work, were observational studies where the core always was the physical interpretation of the observations or the diagnostic results derived from them. He wanted to counteract a tendency to regard the general circulation as nothing but “the statistical manifestation of currents as they appear in the actual atmosphere” and to treat the atmospheric flow as large-scale turbulence, as a substitute for “real knowledge” (Palmén, 1951b). The physical nature of the actual atmosphere could only be understood through detailed analyses of characteristic disturbances. Palmén is one of the few meteorologists who attempted (in 1951) to outline a physical portrait of the general circulation (the others incidentally being his close colleagues Bergeron in 1928 and Rossby in 1941). Prominent in this portrait are the dominant upper-air wind bands, in whose discovery and analysis Palmén played a major role.

It was known already in the 1930s that the wind increased with height, often to speeds of 50–70 meters per second. But it was not until the late 1940s that it was recognized that these strong winds were organized into long, narrow bands, jet streams. Using the technique of vertical cross sections, the same as he had done in the 1930s, Palmén elucidated the nature and dynamics of the midlatitude jet streams and their relation to the Bergen School concept of air-mass fronts. These investigations led Palmén to further studies of energy conversions in the atmosphere.

Existence of what came to be known as the subtropical jet stream had for long been evident in scattered high-level observations of very strong winds at low latitudes. Using a simplified model based on angular momentum conservation Palmén argued that a strong accumulation of momentum ought to be found around 30° latitude. This is where the air, which has been heated in the equatorial belt and then risen to about 10 kilometers’ height, starts to accelerate away from the tropics, starts to be deflected eastward due to Earth’s rotation and is thus barred from further progress poleward. Of special importance was the important distinction he made between this subtropical jet stream and the midlatitude jet streams that were caused by local thermal contrast along the border zones of neighboring air masses.

It was remarkable that Palmén, a meteorologist raised and educated at northern latitudes, made fundamental contributions to the dynamics of tropical cyclones. Through investigations of a hurricane crossing Florida in autumn 1947 Palmén reached the conclusion that tropical cyclones can form only if the ocean surface temperature exceeds 27 degrees Celsius. On a visit to the United States in October 1954 Palmén observed Hurricane Hazel and was able to calculate the internal release of kinetic energy.

Half a year after Palmén had left Finland the Helsinki University authorities decided to appoint Palmén to the chair. But Palmén had by now settled well in the United States and would need more to convince him to come home. He was in particular not happy with the lack of recognition of general sciences in Finland. Just before his departure, he had published an article in a journal on “the economic plight of science in Finland” (Palmén, 1946). There he gave voice to Finnish scientists, who did not see any future for scientific research in their home country. Many of them had already emigrated.

The article stirred a nationwide debate that two years later resulted in the revival of the old project about a Finnish academy. Among those elected was Erik Palmén, then still in Chicago. These signs of recognition acted strongly to make him return home. It meant the possibility of continuing research and maintaining international contacts in the field of dynamic meteorology. It also paid off well for Finland: in the early 1960s, thanks to Palmén’s wide international outlook and travel funds, some of his students started to work on problems in the new and promising field of numerical weather prediction.

Palmén’s sixtieth birthday was marked by an international celebration. In 1956 he was awarded the Symonds Memorial Gold Medal by the Royal Meteorological Society and in 1960, together with Jacob Bjerknes, the AMS Rossby Prize for “their pioneering and distinguished research contributions and synoptic aerology which had given a unified picture of the general circulation of the atmosphere.” He was awarded the Swedish Rossby Prize in 1966 and in 1968 the Silver Medal of the Finnish Geophysical Society (in 1988 renamed the Erik Palmén medal). After his retirement in 1963 Palmén began work with his student Chester W. Newton on a comprehensive textbook on circulation processes in the atmosphere from the large-scale weather patterns covering most of continents down to thundery squall-lines.

Palmén’s Personality In 1923 Erik Palmén married Synnöve Maria von Hellens, a teacher of mathematics. They had two children: Ann Marie (Mrs. Walter Hackman) and Lars Johan.

The common image of Palmén, conveyed by the traditional photo, shows the formal stern side of his person. His friends and colleagues knew him as an enthusiastic and open-minded scientist, never hesitating to enter into any discussion, whether it was about meteorology, nature, or world affairs. Journalists who interviewed him noted his preference for “counter-opposing views,” and provocative statements, the reaction to which he awaited with “jubilant wrinkles around the sunken brown eyes” (Marcella, 1955).

Among those “provocative statements” was his often expressed opinion that anything more than four to five years of basic university education led only to being conformist. “The scientific mind withers away, bored and tired of reading too much.” Like other members of the Bergen School, most notably Vilhelm Bjerknes himself, Palmén credited his own success partly because he was himself “merely an amateur” in this special field: “I was, obviously, unburdened by prejudicial opinions and theories. It is often good not to have too much knowledge” (Marcella, 1968).

BIBLIOGRAPHY

WORKS BY PALMÉN

With Jacob Bjerknes. “Investigations of Selected European Cyclones by Means of Serial Ascents. Case 4: February 15–17 1935.” Geophysiske Publikasjoner12, no. 2 (1937): 1–62.

Vetenskapens Ekonomiska Nödläge I Finland (The economic plight of science in Finland), Nya Argus, March 1946.

With Staff Members of the Department of Meteorology of the University of Chicago. “On the General Circulation of the Atmosphere in Middle Latitudes.” Bulletin of the American Meteorological Society 28 (1947): 255–280. “The Aerology of Extratropical Disturbances.” Compendium of

Meteorology, edited by Thomas F. Malone. Boston: American Meteorological Society, 1951a. “The Role of Atmospheric Disturbances in the General

Circulation.” Quarterly Journal of the Royal Meteorological Society 77 (1951b): 337–354. Symons Memorial Lecture.

With Chester W. Newton. Atmospheric Circulation Systems: Their Structure and Physical Interpretation. New York: Academic Press, 1969. “Personal Recollections about the Bergen School.” Translated and edited from a lecture given in Finnish at the Department of Meteorology, University of Helsinki, 21 February 1979. Available from the Department of Meteorology, University of Helsinki. “Muistelmia Bergenin ja Chicagon koulukunnan ajoilta.”

Lecture given in Finnish at the Department of Meteorology, University of Helsinki, 1979. Available from the Department of Meteorology, University of Helsinki.

“In My Opinion ….” Geophysica 21, no. 1 (1985): 5–18. Autobiographical notes and bibliography.

OTHER SOURCES

Holopainen, Eero. “Erik Herbert Palmén.” Geophysica 21 (1985): 1–3.

Marcella [Margareta Normeen]. 1955, Interview with Erik Palmén. Hufudstadsbladet, Helsinki, 29 July 1955.

———. 1968, Interview with Erik Palmén. Hufudstadsbladet, Helsinki, 30 August 1968.

Newton, Chester W. “Erik Palmén: Synthesizer of the Atmospheric General Circulation.” Bulletin of the American Meteorological Society 67, no. 3 (1986): 282–293.

———, and Eero O. Holopainen, eds. “The Life Cycle of Extratropical Cyclones.” The Erik Palmén Memorial Volume. American Meteorological Society, 1990. Contains scientific articles on atmospheric dynamics by friends and colleagues of Erik Palmén, who in 1988, three years after his death and on the ninetieth anniversary of his birth, had organized an international symposium in Helsinki.

Riehl, Herbert. “Erik Palmén 1898–1985.” Quarterly Journal of the Royal Meteorological Society 111 (1985): 1142–1143. Obituary.

Taba, H. “The Bulletin Interviews: Professor E. H. Palmén.” WMO Bulletin 30 (1981): 92–100.

Anders Persson