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Knut Ångström

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Knut Johan Ångström
Born12 January 1857
Died4 March 1910 (1910-03-05) (aged 53)
AwardsBjörkénska priset (1905)
Scientific career
InstitutionsUppsala University

Knut Johan Ångström (12 January 1857 – 4 March 1910) was a Swedish physicist. He was the son of physicist Anders Jonas Ångström and studied in Uppsala from 1877 to 1884, when he received his licentiat-degree, before going for a short time to the University of Strassburg (Strasbourg) to study with August Kundt. Coming back to Uppsala, he completed his doctoral degree and was appointed lecturer in physics at the new university college in Stockholm (now Stockholm University) in 1885. After a few years working there, he returned to Uppsala in 1891 and received the professorship of Physics in 1896.[1]

He focused his research work on investigating the radiation of heat from the sun,[2] terrestrial nocturnal emission and its absorption by the Earth's atmosphere,[3] and to that end devised various delicate[clarification needed] methods and instruments, including his electric compensation pyrheliometer,[4] invented in 1893, apparatus for obtaining a photographic representation of the infra-red spectrum (1895)[5] and pyrgeometer[6] (abt. 1905).

In 1900, Herr J. Koch, laboratory assistant to Knut Ångström, did not observe any appreciable change in the absorption of infrared radiation by decreasing the concentration of CO2 up to a third of the initial amount.[7] This result, in addition to the observation made a couple of years before that the superposition of the water vapour absorption bands,[8] more abundant in the atmosphere, over those of CO2, convinced some geologists for a time that calculations by Svante Arrhenius for CO2 warming were wrong; though subsequent work in following decades eventually vindicated Arrhenius.[9][10]

The experiment, however, was careless seen from the current perspective with erroneous result[11] but of a historical significance in the development of the theory of the greenhouse effect amplified by CO2.

He was elected a member of the Royal Swedish Academy of Sciences in 1893.


  1. ^ Chisholm 1911.
  2. ^ Ångström, A. K.; Drummond, A. J. (1966). "Note on solar radiation in mountain regions at high altitude". Tellus. 18 (4): 801–805. Bibcode:1966Tell...18..801A. doi:10.3402/tellusa.v18i4.9706.
  3. ^ Abbot, C. G. (February 1920). "The Larger Opportunities for Research on the Relations of Solar and Terrestrial Radiation". Proceedings of the National Academy of Sciences of the United States of America. 6 (2): 82–95. Bibcode:1920PNAS....6...82A. doi:10.1073/pnas.6.2.82. ISSN 0027-8424. PMC 1084415. PMID 16576466.
  4. ^ Nilsson, Åke. "Knut Ångström - Gustavianum - Uppsala University, Sweden". gustavianum.uu.se. Retrieved 2019-02-09.
  5. ^  One or more of the preceding sentences incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "Angström, Anders Jonas s.v. Knut Johan Ångström". Encyclopædia Britannica. Vol. 2 (11th ed.). Cambridge University Press. p. 42.
  6. ^ Interview With Dr Anders K. Ångström (Knut's son), WMO Bulletin 1982 "an excellent opportunity for me to use my father's radiation instruments, the pyrheliometer and the instrument for measuring outgoing nocturnal radiation to which I had already given the name pyrgeometer"
  7. ^ Ångström K (1900). "Ueber die Bedeutung des Wasserdampfes und der Kohlensäure bei der Absorption der Erdatmosphäre" (PDF). Annalen der Physik. 3 (12): 720–732. Bibcode:1900AnP...308..720A. doi:10.1002/andp.19003081208.
  8. ^ Rubens, H.; Aschkinass, E. (1898-10-01). "Observations on the Absorption and Emission of Aqueous Vapor and Carbon Dioxide in the Infra-Red Spectrum". The Astrophysical Journal. 8: 176. Bibcode:1898ApJ.....8..176R. doi:10.1086/140516. ISSN 0004-637X.
  9. ^ "The Carbon Dioxide Greenhouse Effect". history.aip.org. Retrieved 2019-02-09.
  10. ^ "Knut Angstrom on Atmospheric Absorption" (PDF). Monthly Weather Review. 29 (6): 268. 1901. Bibcode:1901MWRv...29Q.268.. doi:10.1175/1520-0493(1901)29[268a:KAOAA]2.0.CO;2.
  11. ^ "A Saturated Gassy Argument". RealClimate (in German). Retrieved 2019-02-09.

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