Jacob Bjerknes

Jacob Bjerknes

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Jacob Aall Bonnevie Bjerknes (November 2, 1897 – July 7, 1975) was a Norwegian-American meteorologist
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...

.

Background


Jacob Aall Bonnevie Bjerknes was born in Stockholm, Sweden. His father was the Norwegian
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 meteorologist Vilhelm Bjerknes, one of the pioneers of modern weather forecasting. His paternal grandfather was noted Norwegian mathematician and physicist, Carl Anton Bjerknes
Carl Anton Bjerknes
Carl Anton Bjerknes was a Norwegian mathematician and physicist. Bjerknes' earlier work was in pure mathematics, but he is principally known for his studies in hydrodynamics.-Biography:...

. His maternal grandfather was Norwegian politician, Jacob Aall Bonnevie
Jacob Aall Bonnevie
Jacob Aall Bonnevie was a Norwegian school director and a politician for the Conservative Party. Born in Christiania , he was the son of Honoratus Bonnevie who later became mayor of the city...

  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
University of Leipzig
The University of Leipzig , located in Leipzig in the Free State of Saxony, Germany, is one of the oldest universities in the world and the second-oldest university in Germany...

. 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
Weather front
A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front...

, that is, sharply defined boundaries between air masses. This concept is known as the Norwegian cyclone model
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 along a frontal boundary, eventually occluding and...

.

Bjerknes returned to Norway in where in 1917, his father founded the Geophysical Institute, University of Bergen
Geophysical Institute, University of Bergen
Geophysical Institute, University of Bergen is a marine research facility located in Bergen, Norway. Founded in 1917 by Bjørn Helland-Hansen, the institute studies the field of oceanography dealing with the variation patterns of the weather in the North Atlantic Ocean off the coast of Norway....

 in Bergen
Bergen
Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , ....

. 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 Rossby
Carl-Gustaf Arvid Rossby was a Swedish-U.S. meteorologist who first explained the large-scale motions of the atmosphere in terms of fluid mechanics....

 and Tor Bergeron
Tor Bergeron
Tor Bergeron was the 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 supercooled water and ice crystals...

. 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
University of Oslo
The University of Oslo , formerly The Royal Frederick University , is the oldest and largest university in Norway, situated in the Norwegian capital of Oslo. The university was founded in 1811 and was modelled after the recently established University of Berlin...

 in 1924.

In 1926, Jacob Bjerknes was a support meteorologist when Roald Amundsen
Roald Amundsen
Roald Engelbregt Gravning Amundsen was a Norwegian explorer of polar regions. He led the first Antarctic expedition to reach the South Pole between 1910 and 1912 and he was the first person to reach both the North and South Poles. He is also known as the first to traverse the Northwest Passage....

 made the first crossing of the Arctic in the airship Norge
Norge (airship)
The Norge was a semi-rigid Italian-built airship that carried out what many consider the first verified overflight of the North Pole on May 12, 1926. It was also the first aircraft to fly over the polar ice cap between Europe and America...

. 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
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...

 during the 1933-1934 school year and emigrated to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 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
University of California, Los Angeles
The University of California, Los Angeles is a public research university located in the Westwood neighborhood of Los Angeles, California, USA. It was founded in 1919 as the "Southern Branch" of the University of California and is the second oldest of the ten campuses...

.

Bjerknes founded the UCLA 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 low-index conditions. 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 El Niño
El Niño-Southern Oscillation
El Niño/La Niña-Southern Oscillation, or ENSO, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years...

 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.

Honors


In 1933, Jacob Bjerknes became a member of the Norwegian Academy of Science and Letters
Norwegian Academy of Science and Letters
The Norwegian Academy of Science and Letters is a learned society based in Oslo, Norway.-History:The University of Oslo was established in 1811. The idea of a learned society in Christiania surfaced for the first time in 1841. The city of Throndhjem had no university, but had a learned...

 and the Royal Swedish Academy of Science. Over the years he received numerous honors from various societies. Jacob Bjerknes was made a Knight 1st Class of the Royal Norwegian Order of St. Olav during 1947. Jacob Bjerknes died during 1975 in Los Angeles, California
Los Angeles, California
Los Angeles , with a population at the 2010 United States Census of 3,792,621, is the most populous city in California, USA and the second most populous in the United States, after New York City. It has an area of , and is located in Southern California...

.

Awards

  • American Geophysical Union
    American Geophysical Union
    The American Geophysical Union is a nonprofit organization of geophysicists, consisting of over 50,000 members from over 135 countries. AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international field of geophysics...

      William Bowie Medal
    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"...

     (1945)
  • Swedish Society for Anthropology and Geography
    Swedish Society for Anthropology and Geography
    The Swedish Society for Anthropology and Geography is a scientific learned society founded in Sweden in 1877...

     Vega Medal (1958)
  • World Meteorological Organization
    World Meteorological Organization
    The World Meteorological Organization is an intergovernmental organization with a membership of 189 Member States and Territories. It originated from the International Meteorological Organization , which was founded in 1873...

     Award (1959)
  • American Meteorological Society
    American Meteorological Society
    The American Meteorological Society promotes the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications. Founded in 1919, the American Meteorological Society has a membership...

     Carl-Gustaf Rossby Research Medal
    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...

     (1960)
  • National Medal of Science
    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 sciences, biology, chemistry, engineering, mathematics and...

     (1966)

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