Modern Contributors to Meteorology (post World War I)

Below are checklists of Modern Contributors to Meteorology on postal items (stamps, souvenir sheets, aerogrammes, postal cards, etc.) and numismatic items (banknotes and coins). Catalog numbers, years of issue, and notes on the items featured are given when available. If readers know of additional information or images, please contact the authors using the e-mail addresses at the bottom of this page.

For (both chronological and alphabetical) lists of contributors to meteorology return to the Meteorologist Index.

See also the following categories of Contributors to Meteorology:

• Ancient and pre-Renaissance Contributors to Meteorology (through 1300s AD)
• Precursor Contributors to Meteorology (Renaissance [~1400 AD] through World War I)

The following persons are presented in chronological order. See the bottom of this page for footnotes that are common to all of the tables below.

Wilson, Charles Thomson Rees (1869 - 1959)

Wilson was a British physicist who shared the 1927 Nobel Prize in Physics with Arthur Compton. Wilson was cited for "his method of making the paths of electrically charge particles visible by condensation of vapour".

Wilson's primary scientific interest was in what is now known as cloud physics. He was inspired in 1894 to begin research into cloud processes after working at the Ben Nevis Observatory. He then worked until 1900 as a researcher at the Cavendish Laboratory (Cambridge University), where he developed his cloud chamber and began to investigate the behaviour of ions as cloud condensation nuclei. In 1911, he used the cloud chamber for the first time to see the tracks of individual alpha and beta particles and electrons. Around that time he also made observations of atmospheric electricity and developed several types of electrometers, and put forth a theory of thunderstorm activity.

Wilson used the cloud chamber to demonstrate the processes involved in the formation of cloud droplets and raindrops. His starting point was Aitken's work that showed that bits of dust in the air would serve as "nuclei" upon which moisture would condense in air cooling by expansion (due, for example, to rising motion). Wilson proved that condensation in pure air (with no dust particles at all) could only occur at much colder temperatures than it would in the presence of dust. The dust particles became known as cloud condensation nuclei (CCN). In the real atmosphere, CCN are considered to always be involved in the formation of cloud droplets. Wilson also showed that if the dust particles were negatively charged, then they would tend to condense more vapour than if they were positively charged. He suggested therefore that raindrops descending to the ground might in general be negatively charged, which would explain the negative charge of the Earth compared to the positive charge of the atmosphere.

Wilson also conducted some experiments with the cloud chamber in which he showed that passing certain types of radiation (such as ultraviolet light) through dustless air would produce apparent invisible nuclei on which vapour would condense as easily as on dust particles.

Langmuir, Irving (1881 - 1957)

Irving Langmuir was an American physical chemist who spent much of his career with the General Electric corporation. He was awarded the Nobel prize for chemistry in 1932, but is remembered by meteorologists mostly for his pioneering work in the area of weather modification through cloud seeding.

He invented the Langmuir probe, an instrument designed to measure the properties of ionized gases (known as 'plasma', a term that he coined in 1927) in the upper atmosphere. In 1946, a Langmuir probe and other instruments were carried aloft from White Sands Missile Range by a V2 rocket. Although the V2 failed, the launch marked the first attempt to explore the upper atmosphere through direct measurements by rocket-borne instruments.

Langmuir had a strong interest in meteorology, particularly in the area of cloud microphysics. In the war years, he was involved in research on smoke screens and on aircraft de-icing capabilities. He and his colleague Vincent Schaefer invented the artificial fog smoke screen generator widely used during WWII. This work led him to think about clouds in general, and airborne particulates and ice nucleation in particular. In 1946, Langmuir and Schaefer realized that clouds might be modified by "seeding" them with dry ice pellets. The dry ice supplied to the cloud would form extra ice particles to which cloud water would migrate, resulting in more cloud droplets and potentially more rain. They demonstrated the effect later that year. Their work continued in the post-war years with dry ice and also silver iodide as seeding agents. The hope was that a certain amount of seeding could induce clouds to produce rain, while overseeding could potentially reduce hail and so reduce hail damage to crops. The work was controversial, and considerations of possible financial liability led GE to turn the program over to the military in 1947. The military continued to conduct cloud seeding experiments, some of which were carried out in the area of Socorro, New Mexico, which since 1963 has been home to the Irving Langmuir Laboratory for Atmospheric Research.

Wegener, Alfred (1880 - 1930)

Alfred Wegener was a German geophysicist, Arctic explorer and meteorologist who advanced the theory of continental drift.

Wegener received a doctorate in astronomy in 1904, but found that he was more interested in geophysics, meteorology and climatology. At that time the telegraph, Atlantic cable and wireless were beginning to supply the data necessary for analysis and forecasting of storms. In 1905 he went to work at the Royal Prussian Aeronautical Observatory near Berlin, where he studied the atmosphere with kites and balloons. He was then invited to join a 1906 Danish expedition to Greenland's northeast coast. This was a dream come true for Wegener. In Greenland from 1906 to 1908 Wegener became the first person to use kites and tethered balloons to study the polar atmosphere. From 1909, he lectured on meteorology and astronomy at the University of Marberg. In 1911 he collected his meteorology lectures into a book, Thermodynamik der Atmosphäre (The Thermodynamics of the Atmosphere), which became a standard text in Germany.

Wegener also worked in the area of cloud and precipitation physics. As early as 1784, Benjamin Franklin had speculated that rainfall at the ground began as some form of snow in the clouds. Wegener considered that water can exist in the atmosphere in supercooled liquid form (at a temperature below 0°C), and also that the saturation vapour pressure over liquid water is greater than that over ice. He concluded that as a result, cloud ice crystals would necessarily grow at the expense of supercooled liquid cloud droplets. The resulting large ice crystals would be Franklin's 'snow', which could melt to form raindrops as it fell. These ideas were contained in Thermodynamik der Atmosphäre. Wegener never got the chance to document this process in real clouds, but Tor Bergeron and Walter Findeisen proved the theory in the 1930s. The process, often now known as the Bergeron-Findeisen process, is more correctly referred to as the Wegener-Bergeron-Findeisen process.

Wegener went back to Greenland in 1912-13 and crossed the Greenland ice cap with Danish explorer J.P. Koch and two others in a trip from Dove Bay on the east coast to Upernavik on the west coast. The data that he gathered during this journey made him one of the world's leading experts on polar meteorology and glaciology. According to fellow meteorologist and Greenland explorer Dr. Johannes Georgi, "Wegener was the first to trace storm tracks over the Greenland ice cap". He continued to work at Marburg until 1919, when he was appointed head of the Departement of theoretical meteorology at the German Hydrographic Office (The Deutsche Seewarte) in Hamburg. In 1924 he was appointed professor of Meteorology and Geophysics at the Institute of Physics, University of Graz. In addition to his continuing interest in continental drift and polar meteorology, he also conducted investigations concerning processes in the upper atmosphere and the aurora borealis. Furthermore, he also studied optical effects in the frigid air above the Greenland ice cap, where spectacular optical phenomena can occur in the presence of ice crystals. In a 1926 article, Wegener explained the formation process of two rare arcs that can appear opposite the sun in the presence of ice crystals. The arcs were then named in his honour.

In addition to his meteorological work, Wegener originated a revolution in geophysics: the idea of continental drift. This theory accounted for geological and fossil evidence that ancient climates had been vastly different from modern ones. Wegener thought that actual motion of continents might explain this climatic puzzle, so he and the climatologist Wladimir Köppen (who was also his father-in-law) plotted ancient deserts, jungles and ice sheets on paleogeographic maps based on the theory. The result was a plausible picture of past climates. Evidence of an ice age from some 280 million years ago, for example, scattered over almost all the Earth in modern times, clustered neatly around the South Pole in Wegener's map. This was because Africa, Antarctica, Australia and India had once comprised a southern hemispheric supercontinent (Gondwanaland). Wegener considered such paleoclimatic validation one of the strongest proofs of his theory. Conversely, continental drift has since become one main supporting principles of paleoclimatology.

Wegener returned to Greenland in the spring of 1930 as the leader of an expedition designed to systematically study the Greenland ice cap and its climate. Ernst Sorge, Johannes Giorgi and Fritz Lowe were part of this team. During this expedition, three research stations were set up: West camp, East camp, and Eismitte (Middle Ice camp, located on the ice cap at some 3000 m elevation). Unfortunately, in November 1930 Wegener and Rasmus Villumsen died while trying to reach West camp from Eismitte. Wegener was only 50.

Germany's Alfred Wegener Institute for Polar and Marine research, established in 1980, was named in honour of Wegener.

Other selected publications by Wegener:

• Durch die weiße Wüste (The Crossing of the Ice Cap, 1912-13) (1919)
• The Origin of Continents and Oceans (published in German in 1912 and 1915, and translated to other languages in 1922)
• Die Klimate der Geologischen Vorzeit (The Climates of the Geological Past) (with W. Köppen, 1924).

Sorge, Ernst (1899 - 1946)

Sorge was a German geographer, glaciologist and polar researcher who participated in the German Greenland expedition of 1930 with meteorologists Alfred Wegener, Johannes Giorgi and Fritz Lowe. The expedition studied the meteorology and glaciology of the Greenland ice cap. Unfortunately Wegener died during this expedition.

Georgi would later describe Sorge's work: "Sorge measured the density of blocks of nevé cut at different levels of his shaft. He succeeded, with this primitive equipment, in distinguishing the strata of the precipitation of summer and winter, and of measuring its content of water, for 20 years back to 1911!" This pioneering research on the glaciology and climatology of Greenland was conducted during the winter of 1930-31 at the Eismitte station on the Greenland ice cap.

von Neumann, John (1903 - 1957)

John von Neumann was born in Hungary, but immigrated with his family to the United States in 1930. He was a mathematician, computer scientist and meteorologist who pioneered the use of computers in applied scientific problems, including meteorology.

In 1946 he announced his "intention of developing a very high speed electronic computing machine". In collaboration with the US Weather Bureau, the Navy and the Air Force, he formed the Meteorology Group at Princeton's Institute for Advanced Study (IAS). His computer work proceeded apace at the IAS during the late 1940s, culminating in the revolutionary computing machine ENIAC. The world's first computerized weather forecast was produced in 1950 by ENIAC. This pioneering work in numerical weather prediction (NWP) was described in a scientific paper written by von Neumann and his colleagues Jule Charney and Ragnar Fjörtoft in 1950. Entitled Numerical Integration of the Barotropic Vorticity Equation (published in the meteorological journal Tellus, Vol 2, pp 237-254), it is the earliest scientific paper in the area of NWP.

Von Neumann also pursued his other meteorological interest: "calculating the effects of human intervention in the natural processes of the atmosphere". He proposed to apply computer techniques to study the idea of adding dye to the polar icecaps to decrease the amount of solar energy they would reflect. He claimed that the procedure could warm the Earth enough to make the climate of Iceland approximate that of Hawaii. He also predicted the warming of the climate due to carbon dioxide release.

In 1953, the US Advisory Committee on Weather Control was created to oversee American weather modification and cloud seeding activities, such as those originated by Irving Langmuir and Vincent Schaefer after WWII. Von Neumann became involved with the Committee in 1955 (at the time he was also a commissioner of the Atomic Energy Commission, and so was involved with the development and stockpiling of nuclear weapons). He believed that in weather control as well as in the nuclear arms race, the US had to stay ahead of the Soviets at all costs. Like the US military, he considered weather control as a potential tool for achieving global dominance, and as part of the Advisory Committee he participated in a panel on the "possible effects of atomic and thermonuclear explosions in modifying weather". Another area of discussion was how Soviet harvests might be ruined by a US-induced drought. Yet another was that atomic bombs detonated off the west coast of Africa at the onset of the monsoon might improve the climate of the drought-prone Sahel region. As von Neumann naively told Congress in 1956, "our knowledge of the dynamics in the atmosphere is rapidly approaching a level that will make possible, in a few decades, intervention in the atmospheric and climatic matters. It will probably unfold on a scale difficult to imagine at present. There is little doubt one could intervene on any desired scale, and ultimately achieve rather fantastic effects". But already in 1957, Roger Revelle and Hans Seuss were raising warning flags with their ominous findings on increasing CO₂ levels in the Earth's atmosphere which hinted at anthropogenic global warming. It seems that von Neumann never considered, at least in public, that major weather modification projects carried out in the atmosphere might spiral out of control and lead to unexpected effects.

Rowland, F. Sherwood (1927 - present)

Rowland is an American physicist who has conducted research into ozone. In 1974 he and Mario J. Molina published a seminal article in Nature in which they discussed the threat posed to the ozone layer by chlorofluorocarbon gases (CFCs) and by the freons used in aerosol spray cans, refrigeration fluids and plastic foams. This followed the work of Paul J. Crutzen, who discovered in 1970 that nitrogen oxides can accelerate ozone destruction. The three received in 1995 the Nobel Prize in physics for their research on ozone. Rowland has continued to work on problems of atmospheric chemistry since his collaboration with Molina in the 1970s.

Crutzen, Paul J. (1933 - present)

Crutzen is a Dutch physicist who conducted upper atmospheric research in the 1960s. This led to a deep interest in the photochemistry of atmospheric ozone, and he became a world expert on the chemical interactions of trace gases and trace components in the atmosphere. In 1970 he discovered that nitrogen oxides can accelerate ozone destruction. Later, he helped develop a theory for the cause of rapid ozone loss in the Antarctic winter, and eventually was involved in international negotiations concerning the restriction of the use of CFCs. Crutzen was director of research at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, from 1977 through 1980, and in 1980 was appointed director of research at the Max Planck Institute in Germany. In 1995, Crutzen, Mario J. Molina and Sherwood F. Rowland were awarded the Nobel Prize in physics for their research on ozone.

Molina, Mario J. (1943 - present)

Molina is a Mexican-born physicist who shared with F. Sherwood Rowland and Paul J. Crutzen in 1995 the Nobel Prize in physics for their research on ozone. Molina and Rowland together published in 1974 a seminal article in Nature in which they discussed the threat posed to the ozone layer by chlorofluorocarbon gases (CFCs) and by the freons used in aerosol spray cans, refrigeration fluids and plastic foams. This followed the work of Crutzen, who discovered in 1970 that nitrogen oxides can accelerate ozone destruction. Molina continued to conduct research on ozone chemistry and the Antarctic ozone "hole" in the 1980s and 1990s. In particular, he demonstrated that chlorine atoms can combine with ozone to form chlorine oxide and oxygen: this simple equation describes the desctruction of ozone by chlorine.

More recently, Molina has led a team studying the effect of aerosols (and in particular sooty sulphurous coal smoke from China and India) on the storm track over the Pacific. His team has used satellite data to analyze deep Pacific storms following wind-blown bursts of pollution. They determined that the aerosols have a climatologically-significant effect, and found increased storm activity that they ascribe to the aerosols.

Footnotes common to all of the tables above:

^*Scott catalog number, unless prefixed with Mi or BL for Michel; KM = Krause and Mishler coin catalog number; P = Pick banknote catalog number; Y = Yoeman coin catalog number.

^**FDC = first day cover; SS# = souvenir sheet, MS# = miniature sheet, where # = number of stamps in sheet, and the numbers in parentheses are the catalog numbers of the stamps in the sheet.

^***The tables include either explicit or implicit birth and death anniversaries if they are indicated by the postal item. In the "Notes on Content" column:

• An explicit anniversary (not in parentheses) is included for a postal item that specifically indicates either the anniversary in question (e.g. "200th anniversary of birth") or the first and last years that determine the anniversary span (e.g. "1804 - 2004").
• An implicit anniversary is presented in parentheses if the year of issue for the postal item is a mulltiple of 100, or 50, or 25 of the number of years from the person's birth or death. The birth and death years may or may not appear on the stamp itself. For example, a stamp issued in 2007 commemorating a person who lived from 1840 to 1907 will be noted by the implicit anniversary phrase "(100th anniv. death)" in the absence of any explicit anniversary mention.

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