Julius Ferdinand von Hann (23 March 1839 in Wartberg ob der Aist near Linz – 1 October 1921 in

Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...

) 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 ...

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 th ...

. He is seen as a father of modern meteorology.

Biography

He was educated at the gymnasium of Kremsmünster and then studied mathematics, chemistry and

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which rel ...

at the

University of Vienna The University of Vienna (german: Universität Wien) is a public research university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world. With its long and rich h ...

, then geology and paleontology under

Eduard Suess Eduard Suess (; 20 August 1831 - 26 April 1914) was an Austrian geologist and an expert on the geography of the Alps. He is responsible for hypothesising two major former geographical features, the supercontinent Gondwana (proposed in 1861) and t ...

and physical geography under Friedrich Simony. From 1865 to 1868, he was master at the ''Oberrealschule'' at Linz, and in 1865 was invited by

Karl Jelinek Karl Jelinek (23 April 1822 in Brünn – 19 October 1876 in Vienna) was an Austrian physicist and meteorologist. Biography From 1839 to 1843 he studied law at the University of Vienna, where he also attended lectures given by mathematician J ...

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, ...

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 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, ...

, the Hann window is a

window function In signal processing and statistics, a window function (also known as an apodization function or tapering function) is a mathematical function that is zero-valued outside of some chosen interval, normally symmetric around the middle of the in ...

, called the Hann function, derived from this technique by

R. B. Blackman Ralph Beebe Blackman (August 29, 1904 – May 24, 1990) was an American mathematician and engineer who was among the pioneers of the information age along with Claude E. Shannon, Hendrik Wade Bode, and John Tukey. Blackman graduated from th ...

and

John Tukey John Wilder Tukey (; June 16, 1915 – July 26, 2000) was an American mathematician and statistician, best known for the development of the fast Fourier Transform (FFT) algorithm and box plot. The Tukey range test, the Tukey lambda distributi ...

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