Marcel Nicolet (1912–1996)

Marcel Nicolet was born on February, 26, 1912, in Basse-Bodeux, Belgium, and died in Uccle/Brussels on October 8, 1996. He received his Ph.D. in 1937 from the University of Liege. He did meteorological forecasting for several years prior to the war, which stopped this activity and launched him into a comprehensive study of the atmospheric attenuation of solar radiation, leading to his famous memoir of 1945, Contribution à 1’Etude de la Structure de l’Ionosphère, which included the ingenious proposal that the quiet D region was formed by the ionization of nitric oxide (NO) by hydrogen Lyman alpha.

Nicolet crossed paths with many of the pioneers of upper atmosphere research. He made ultraviolet observations of the night sky during 1938–1939 at Arosa and studied ozone problems there with Gotz and Dobson. He first met Appleton, Chapman, and Ratcliffe at one of the first international scientific meetings after World War II, a 1946 Union Radio Scientifique International (URSI) meeting held in Paris. Nicolet came to the United States for the first time in January 1950. Invited by Roach to work with Bates in Pasadena on airglow, he met prominent researchers from the University of California, Los Angeles, Caltech, and Mount Wilson Observatory. The collaboration with Bates was fruitful. They had four fundamental papers published in 1950: on hydroxyl (OH) emissions, atmospheric hydrogen, water vapor photochemistry, and sodium D-line emissions. However, most of Nicolet’s papers were of sole authorship and often were quite comprehensive in scope, such as his 1975 thesis on stratospheric ozone. While in California, he and Bates aided Chapman on the proposed division of atmospheric layers from the troposphere to the exosphere. From their knowledge of Greek, Katherine Chapman and Nicolet suggested “mesosphere” for the layer between the stratosphere and the thermosphere.

Passing through Washington, D.C., on his way to California, Nicolet met Berkner and Tuve and spent some time at the Naval Research Laboratory with Hulburt and Tousey. Before returning to Belgium, Nicolet attended a meeting at Penn State, where Berkner and others suggested a campaign similar to the Second International Polar Year (1932–1933), i.e., the International Geophysical Year (IGY). Waynick invited Nicolet to become a Visiting Professor at Penn State, which led to the five Ph.D. degrees granted under his tutelage over the next 20 years. Throughout his career, however, Nicolet remained at the Royal Meteorological Institute, beginning in 1935 as a forecaster for aviation, and in 1946 as Head of its Radiation Division. In 1964 he became the first Director of the Institut D’Aeronomie Spatiale De Belgique, which broke off as a separate entity, a post he retained until 1977. He also served as Secretary-General of the IGY, 1953–1960; President of the International Association of Geomagnetism and Aeronomy, 1963–1967; and longtime member of the Committee on Space Programs and Research (COSPAR) Executive Committee. Concurrently, he held professorships at the Universities of Brussels and Liege and at the Pennsylvania State University.

Nicolet was blessed with a near-photographic memory and began his aeronomic career by reading virtually every pertinent paper. (Now impossible!) He was a pleasure to speak with since he was like a walking library and could cite references in detail, and he was always current. Many benefitted from such talks. A brilliant student, he received first prize, University Exam of Belgium (1935–1937) and Triennial de Potter Prize of the Belgium Royal Academy (1940–1942). His achievements in scientific research (300 published papers) and administration earned him the Guggenheim prize for discovery in Astronautics (1963), the Hodgkins Medal of the Smithsonian Institution for achievements in Aeronomy (1965), the American Geophysical Union’s William Bowie Medal in 1984, memberships in international scientific academies (Belgium, United States, France, and Northern Ireland), and many other distinctions, notably the title of hereditary Baron, conferred by King Boudouin in 1987.

—William Swider

U.S. Air Force Research Laboratory
Hanscom Air Force Base, Massachusetts