Vilhelm Bjerknes

Norwegian geophysicist and meteorologist

• Born: March 14, 1862; Christiania (now Oslo), Norway
• Died: April 9, 1951; Oslo, Norway

Nineteenth-century Norwegian geophysicist and meteorologist Vilhelm Bjerknes is considered a founder of modern meteorology. Bjerknes developed a mathematical theory of fronts and their effects, as well as an influential procedure for numerical weather forecasting, although the computing technology necessary to put his theories to really practical use would not appear until the second half of the twentieth century.

Primary field: Earth sciences

Specialties: Geophysics; meteorology

Early Life

The eldest of three boys, Vilhelm Bjerknes (VIHL-hehlm BYEHRK-nays) was born on March 14, 1862, in Christiania (now Oslo), Norway, to Aletta Koren Bjerknes and Carl Bjerknes, a professor of mathematics at the University of Christiania. Carl Bjerknes was involved in hydrodynamic theory, which is the study of fluids, the forces that act on them, and the forces that are exerted by them.

As Bjerknes grew into adolescence, he was increasingly drawn to his father’s work. Much of his father’s involvement with hydrodynamic theory stemmed from lectures he attended by the German mathematician Gustav Dirichlet. Like his father, Bjerknes was fascinated by Dirichlet’s theories, and worked with his father on experiments to validate them. With his son’s help, the elder Bjerknes was able to validate a theory he had developed, using the principles of hydrodynamics to explain the movement of two interacting objects.

The validation of Carl Bjerknes’s theory in 1875 won acclaim from the scientific community. Vilhelm Bjerknes was thirteen at the time, and father and son continued to work together for years. In 1890, Bjerknes began studying mathematics and physics as an undergraduate at the same university where his father had lectured, which had been renamed the University of Kristiania. His first paper, on hydrodynamic investigations, was published in 1882.

Over time, Carl Bjerknes became increasingly solitary and fearful of others stealing his work. His fears prevented him from publishing his findings. In the final year of his master’s degree, Vilhelm Bjerknes decided to end his collaboration with his father so that he would not be limited professionally, although he would later work to get his father’s hydrodynamics studies published.

Life’s Work

After completing his degree in 1888, Bjerknes received a state scholarship to study in Paris under a mathematical physicist, Jules-Henri Poincaré. Attending Poincaré’s lectures, Bjerknes became interested in the interaction between electrical currents and magnetic fields, known as electrodynamics. His research under Poincaré led him to the work of German physicist Heinrich Hertz. Bjerknes moved in 1890 to Bonn, Germany, to work with Hertz, first as an assistant and later as a partner.

Bjerknes spent the next two years working closely with Hertz. Together, the pair examined electrical resonance. Their findings would later be used in the development of the radio. Bjerknes returned to Norway in 1892, realizing that he needed more academic credentials in order to further his scientific career.

The work Bjerknes had done with Hertz formed the basis of his doctoral thesis, and he was awarded his degree later in 1892. That same year, he met Honoria Bonnevie, whom he would marry in 1893. The School of Engineering in Stockholm, Sweden, offered him a position as a lecturer, which he accepted in 1893. After two years, he became a professor of applied mathematics and mathematical physics at the University of Stockholm. In 1897, Honoria gave birth to their son, Jacob, who would later carry on the legacy of his father and grandfather by becoming a noted meteorologist.

As a professor of applied mathematics and mathematical physics, Bjerknes’s teachings were based in both electrodynamics and hydrodynamics. In 1904, Bjerknes combined his two areas of interest in a way that would guide his research for the rest of his life. By introducing the results of his electrodynamics studies to the analysis of hydrodynamic phenomena, Bjerknes was able to develop the procedure of numerical weather prediction. He had discovered that with enough information about the current state of the atmosphere, it was possible to predict future weather patterns using mathematical formulas.

In 1905, Bjerknes visited the United States to conduct a lecture series based on the findings of his research into the movement of air masses, which he termed “dynamic meteorology.” At the same time, he proposed the possibility of numerical weather prediction. His lectures caught the attention of the Carnegie Institution in Washington, DC; Bjerknes’s research for the next thirty-six years would be funded in part by the organization.

In 1907, Bjerknes returned to the University of Kristiania, where he accepted a position as the head of applied mathematics and mathematical physics. He worked collaboratively with a number of graduate students, and in 1910, the first of three volumes that would define dynamic meteorology was published. In 1912, the University of Leipzig in Germany offered Bjerknes a position as the head of geophysics and the opportunity to be the director of the new Leipzig Geophysical Institute. He accepted, and brought with him many of his collaborators from the University of Kristiania, including his son Jacob. Together, father and son collected data from a series of weather stations they had established around Norway.

In 1917, Bjerknes returned to Norway after accepting an offer to found the Geophysical Institute at the University of Bergen. At the institute, Bjerknes worked with his son, Jacob, and student meteorologists Halvor Solberg and Tor Bergeron. The group theorized that the atmosphere is composed of distinct masses of air meeting at various places to produce different meteorological effects, and that weather activity is confined to narrow zones between masses of warm and cool air, which they called “fronts.” This theory, called the polar front theory, and the subsequent models they created helped define meteorology, the study of the atmosphere. In 1921, Bjerknes published the group’s findings in “On the Dynamics of the Circular Vortex with Applications to the Atmosphere and Atmospheric Vortex and Wave Motions,” which described the life cycle of a cyclone.

Bjerknes made his final career move in 1926, when he returned to the University of Kristiania, renamed the University of Oslo in 1925, as head of applied mathematics and mathematical physics. He left his son to head the Geophysical Institute and returned to teaching. He retired in 1932 at the age of seventy.

Bjerknes remained active after his retirement, becoming president of the Association of Meteorology of the International Union of Geodesy and Geophysics in 1932. Over the years, he was recognized with many awards for his work, including the Agassiz Medal for Oceanography (1926), the Symons Medal for Meteorology (1932), and the Buy-Ballot Medal for Meteorology (1933). He was elected to national academies around the world, and was granted honorary degrees from several universities.

Bjerknes died on April 9, 1951, at the age of eighty-nine.

Impact

The weather forecasting stations established by Bjerknes were a monumental accomplishment. All of the mathematical formulas used for predicting weather were done by hand, since the technology necessary to more accurately predict the weather was not yet available. Still, Bjerknes believed that the ability to forecast the weather would become the primary objective of meteorologists, and his method of numerical weather prediction became the foundation for modern meteorology. In addition, Bjerknes’s concept of weather fronts would become a major aspect of meteorology, and his polar front theory is still used as a tool in weather forecasting.

Technological advances—including radar images, computers, lasers, and satellites—have greatly improved the study of meteorology and enabled meteorologists to more easily and more accurately put Bjerknes’s theories into practice. Meteorological centers use national, international, public, and private resources to predict the weather, such as Doppler radars and weather reports from ships and aircraft. Weather data is transmitted on a daily basis, multiple times a day, to national or regional collecting centers. A model of the atmosphere can be created entirely by entering weather data from around the world into a computer. From there, meteorologists are able to provide the public with weather reports. Their predictions, while often explanations of normal, daily weather patterns, can also help to save lives if a severe storm is developing.

Bibliography

Friedman, Robert Marc. Appropriating the Weather: Vilhelm Bjerknes and the Construction of a Modern Meteorology. Ithaca: Cornell UP, 1989. Print. An overview of Bjerknes’s career, beginning with his father’s work and continuing through his formation of modern meteorology. Covers the science and historical reasoning behind Bjerknes’s research.

Lutgens, Frederick K., Edward J. Tarbuck, and Dennis Tasa. The Atmosphere: An Introduction to Meteorology. 12th ed. Boston: Prentice Hall, 2012. Print. Begins with general concepts about the atmosphere and explains such topics as weather and storm patterns, predictions, climate change, and pollution.

Palmer, Tim, and Renate Hagedorn, eds. Predictability of Weather and Climate. Cambridge: Cambridge UP, 2006. Print. Covers a range of meteorological prediction types in theory and practice from experts in the field.