Julius Ferdinand von Hann (23 March 1839 in
Wartberg ob der Aist
Wartberg ob der Aist is a municipality in the district of Freistadt in the Austrian state of Upper Austria
Upper Austria (german: Oberösterreich ; bar, Obaöstareich) is one of the nine states or of Austria. Its capital is Linz. Upper Aust ...
near Linz – 1 October 1921 in
Vienna) was an
Austria
Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous c ...
n
meteorologist. He is seen as a father of modern meteorology.
Biography
He was educated at the
gymnasium of
Kremsmünster
Kremsmünster is a town in Kirchdorf an der Krems District, in the Austrian state of Upper Austria. Settled in 777, it is home to the Kremsmünster Abbey.
The Abbey was founded 777 by Duke Tassilo III of Bavaria and is one of the oldest abbeys ...
and then studied
mathematics,
chemistry and
physics at the
University of Vienna, then geology and paleontology under
Eduard Suess and physical geography under
Friedrich Simony Friedrich Simony (30 November 1813, Hrochowteinitz – 20 July 1896, Sankt Gallen) was an Austrian geographer and Alpine researcher.
Initially trained as a pharmacist, from 1836 he studied natural sciences at the University of Vienna by way ...
. From 1865 to 1868, he was master at the ''Oberrealschule'' at Linz, and in 1865 was invited by
Karl Jelinek to become the first editor of the ''
Zeitschrift für Meteorologie''. In 1877, he succeeded Jelinek as the director of the
Meteorologische Zentralanstalt (Central Institute for Meteorology and Earth Magnetism) and was appointed professor of meteorology at the University of Vienna. In 1897, he retired as director and became professor of meteorology at the
University of Graz
The University of Graz (german: link=no, Karl-Franzens-Universität Graz, ), located in Graz, Austria, is the largest and oldest university in Styria, as well as the second-largest and second-oldest university in Austria.
History
The univers ...
, but returned to Vienna to fill the chair of professor of cosmic physics in 1900, where he remained until 1910. He became a international honorary member of the
American Academy of Arts and Sciences
The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...
in 1902. In 1912, he was made a foreign knight of the
Prussia
Prussia, , Old Prussian: ''Prūsa'' or ''Prūsija'' was a German state on the southeast coast of the Baltic Sea. It formed the German Empire under Prussian rule when it united the German states in 1871. It was ''de facto'' dissolved by an ...
n ''Ordre Pour le Mérite''.
Hann window
Hann invented a
weighted moving average
In statistics, a moving average (rolling average or running average) is a calculation to analyze data points by creating a series of averages of different subsets of the full data set. It is also called a moving mean (MM) or rolling mean and is ...
technique for combining meteorological data from neighboring regions, using the weights
/4, 1/2, 1/4 known as ''Hann smoothing''.
In
signal processing
Signal processing is an electrical engineering subfield that focuses on analyzing, modifying and synthesizing ''signals'', such as sound, images, and scientific measurements. Signal processing techniques are used to optimize transmissions, d ...
, the Hann window is a
window function, called the
Hann function, derived from this technique by
R. B. Blackman and
John Tukey in 1959. Here, the use of the Hann window is called "hanning", e.g., "hanning" a signal is to apply the Hann window to it.
Works
* Die Erde als Ganzes, ihre Atmosphäre und Hydrosphäre, 1872, 5th edition 1896
* Handbuch der Klimatologie, first issued 1883, revised editions until 1911
**
* Atlas der Meteorologie, 1887
* Allgemeine Erdkunde. Ein Leitfaden der astronomischen Geographie, Meteorologie, Geologie und Biologie, 5th edition 1896
* Lehrbuch der Meteorologie, 1901, 3rd edition 1915
He contributed many papers to the ''Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften''.
Notes
References
*
* "Hann, Julius Ferdinand von." Complete Dictionary of Scientific Biography. 2008. Encyclopedia.com. (June 26, 2014)
{{DEFAULTSORT:Hann, Julius Von
Austrian meteorologists
Austrian untitled nobility
Recipients of the Buys Ballot Medal (Netherlands)
Recipients of the Pour le Mérite (civil class)
1839 births
1921 deaths
Academic staff of the University of Vienna
Members of the Royal Society of Sciences in Uppsala