Jacob Aall Bonnevie Bjerknes ( , ; 2 November 1897 – 7 July 1975) was a

meteorologist A meteorologist is a scientist who studies and works in the field of meteorology aiming to understand or predict Earth's atmospheric phenomena including the weather. Those who study meteorological phenomena are meteorologists in research, while t ...

. He is known for his key paper in which he pointed the dynamics of the polar front, mechanism for north-south heat transport and for which he was also awarded a doctorate from the University of Oslo. Born in Stockholm, Sweden, he was the son of the Norwegian meteorologist Vilhelm Bjerknes, one of the pioneers of modern weather forecasting. He helped develop the Norwegian cyclone model. He earned a Ph.D. from the University of Oslo in 1924. Bjerknes was part of the team that made the first crossing of the Arctic in the airship

Norge Norge is Norwegian (bokmål), Danish and Swedish for Norway. It may also refer to: People * Kaare Norge (born 1963), Danish guitarist * Norge Luis Vera (born 1971), Cuban baseball player Places * 11871 Norge, asteroid Toponyms: *Norge, Okla ...

. During WWII, he helped the US with the planning of the Hiroshima and Nagasaki atomic bombings. He also helped gain an understanding of the weather phenomenon

El Niño El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date ...

Background

Jacob Aall Bonnevie Bjerknes was born in

Stockholm, Sweden Stockholm () is the capital and largest city of Sweden as well as the largest urban area in Scandinavia. Approximately 980,000 people live in the municipality, with 1.6 million in the urban area, and 2.4 million in the metropolita ...

. His father was the Norwegian meteorologist Vilhelm Bjerknes, one of the pioneers of modern weather forecasting. His paternal grandfather was Norwegian mathematician and physicist Carl Anton Bjerknes. His maternal grandfather was Norwegian politician

Jacob Aall Bonnevie Jacob Aall Bonnevie (31 December 1838 – 13 August 1904) was a Norwegian educator, school director and text book author. He served as a member of the Norwegian Parliament for the Conservative Party. Biography Bonnevie was born in Christi ...

, after whom he was named.

Professional career

Bjerknes was part of a group of meteorologists led by his father, Vilhelm Bjerknes, at the

University of Leipzig Leipzig University (german: Universität Leipzig), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December ...

. Together they developed the model that explains the generation, intensification and ultimate decay (the life cycle) of mid-latitude cyclones, introducing the idea of fronts, that is, sharply defined boundaries between air masses. This concept is known as the

Norwegian cyclone model The older of the models of extratropical cyclone development is known as the Norwegian cyclone model, developed during and shortly after World War I within the Bergen School of Meteorology. In this theory, cyclones develop as they move up and alon ...

. Bjerknes returned to Norway in 1917, where his father founded the Geophysical Institute, University of Bergen in

Bergen Bergen (), historically Bjørgvin, is a city and municipalities of Norway, municipality in Vestland county on the Western Norway, west coast of Norway. , its population is roughly 285,900. Bergen is the list of towns and cities in Norway, secon ...

. They organized an analysis and forecasting branch which would evolve into a weather bureau by 1919. The scientific team at Bergen also included the Swedish meteorologists

Carl-Gustaf Rossby Carl-Gustaf Arvid Rossby ( 28 December 1898 – 19 August 1957) was a Swedish-born American meteorologist who first explained the large-scale motions of the atmosphere in terms of fluid mechanics. He identified and characterized both the jet ...

and

Tor Bergeron Tor Bergeron (15 August 1891 – 13 June 1977) was a Swedish meteorologist who proposed a mechanism for the formation of precipitation in clouds. In the 1930s, Bergeron and W. Findeisen developed the concept that clouds contain both supercoole ...

. As pointed out in a key paper by Jacob Bjerknes and Halvor Solberg (1895-1974) in 1922, the dynamics of the polar front, integrated with the cyclone model, provided the major mechanism for north-south heat transport in the atmosphere. For this and other research, Jacob Bjerknes was awarded the Ph.D. from the

University of Oslo The University of Oslo ( no, Universitetet i Oslo; la, Universitas Osloensis) is a public research university located in Oslo, Norway. It is the highest ranked and oldest university in Norway. It is consistently ranked among the top universit ...

in 1924.''Halvor Solberg''
(Store norske leksikon) In 1926, Jacob Bjerknes was a support meteorologist when

Roald Amundsen Roald Engelbregt Gravning Amundsen (, ; ; 16 July 1872 – ) was a Norwegian explorer of polar regions. He was a key figure of the period known as the Heroic Age of Antarctic Exploration. Born in Borge, Østfold, Norway, Amundsen beg ...

made the first crossing of the Arctic in the airship

. In 1931, he left his position as head of the National weather service at Bergen to become professor of meteorology at the Geophysical Institute at the University of Bergen. Jacob Bjerknes lectured at the

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of th ...

during the 1933-1934 school year and emigrated to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

in 1940, where he headed a government-sponsored meteorology annex for weather forecasting, at the department of physics of the

University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the Californ ...

. During the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

Bjerknes was in the US armed forces, and serving as a colonel in the US Air Force he helped determine the best dates for the

atomic bombings of Hiroshima and Nagasaki The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August 1945, respectively. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the onl ...

. Bjerknes founded the

UCLA The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California ...

Department of Meteorology (now the Department of Atmospheric and Oceanic Sciences). As a professor at the University of California, he was the first to see a connection between unusually warm sea-surface temperatures and the weak easterlies and heavy rainfall that accompany . At UCLA, Bjerknes and fellow Norwegian-American meteorologist, Jorgen Holmboe, further developed the pressure tendency and the extratropical cyclone theories. In 1969, Jacob Bjerknes helped toward an understanding of

Southern Oscillation, by suggesting that an anomalously warm spot in the eastern Pacific can weaken the east-west temperature difference, disrupting trade winds, which push warm water to the west. The result is increasingly warm water toward the east.

Personal life

In 1928, he married Hedvig Borthen (1904–1998). They were the parents of two children. He died on 7 July 1975 in

Los Angeles, California Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the List of municipalities in California, largest city in the U.S. state, state of California and the List of United States cities by population, sec ...

Honors and awards

He was made an Honorary Member of the

Royal Meteorological Society The Royal Meteorological Society is a long-established institution that promotes academic and public engagement in weather and climate science. Fellows of the Society must possess relevant qualifications, but Associate Fellows can be lay enthus ...

in 1932 and a member of both the

Norwegian Academy of Science and Letters The Norwegian Academy of Science and Letters ( no, Det Norske Videnskaps-Akademi, DNVA) is a learned society based in Oslo, Norway. Its purpose is to support the advancement of science and scholarship in Norway. History The Royal Frederick Unive ...

and the Royal Swedish Academy of Science in 1933. *

Symons Gold Medal The Symons Gold Medal is awarded biennially by the Royal Meteorological Society for distinguished work in the field of meteorological science. It was established in 1901 in memory of George James Symons, a notable British meteorologist. Recipients ...

(1940) *

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's ...

William Bowie Medal The William Bowie Medal is awarded annually by the American Geophysical Union for "outstanding contributions to fundamental geophysics and for unselfish cooperation in research". The award is the highest honor given by the AGU and is named in honor ...

(1945) * Knight 1st Class of the Royal Norwegian Order of St. Olav (1947). *

Swedish Society for Anthropology and Geography The Swedish Society for Anthropology and Geography (SSAG; sv, Svenska Sällskapet för Antropologi och Geografi) is a scientific learned society founded in December 1877. It was established after a rearrangement of various sections of the Anthropo ...

Vega medal The Swedish Society for Anthropology and Geography (SSAG; sv, Svenska Sällskapet för Antropologi och Geografi) is a scientific learned society founded in December 1877. It was established after a rearrangement of various sections of the Anthropo ...

(1958) *

World Meteorological Organization The World Meteorological Organization (WMO) is a specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophysics. The WMO originated from the Inter ...

International Meteorological Organization Prize The International Meteorological Organization Prize is awarded annually by the World Meteorological Organization (WMO) for outstanding contributions in the field of meteorology and, since 1971, the field of operational hydrology. The prize, estab ...

(1959). *

American Meteorological Society The American Meteorological Society (AMS) is the premier scientific and professional organization in the United States promoting and disseminating information about the atmospheric, oceanic, and hydrologic sciences. Its mission is to advance th ...

Carl-Gustaf Rossby Research Medal The Carl-Gustaf Rossby Research Medal is the highest award for atmospheric science of the American Meteorological Society. It is presented to individual scientists, who receive a medal. Named in honor of meteorology and oceanography pioneer Carl- ...

(1960) *

National Medal of Science The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social scienc ...

(1966) *

American Academy of Achievement The American Academy of Achievement, colloquially known as the Academy of Achievement, is a non-profit educational organization that recognizes some of the highest achieving individuals in diverse fields and gives them the opportunity to meet ...

- Golden Plate Award (1967)

References

External links

Biographie de Jacob Bjerknes
by Arnt Eliassen
Tribute to J. Bjerknes on the 100th anniversary of his birthJacob Bjerknes photographNational Academy of Sciences Biographical Memoir
{{DEFAULTSORT:Bjerknes, Jacob 1897 births 1975 deaths National Medal of Science laureates Norwegian meteorologists Norwegian climatologists Carl-Gustaf Rossby Research Medal recipients Norwegian emigrants to the United States Members of the Norwegian Academy of Science and Letters Recipients of the St. Olav's Medal Jakob Bonnevie family