Pavel Alexandrovich Molchanov (Russian: Павел Александрович Молчанов) (February 18 [O.S. February 6] 1893 in Volosovo, Russian Empire – October 1941, Leningrad, Russian SFSR) was a Soviet Russian meteorologist and the inventor of the radiosonde.
He graduated from Petersburg University in 1914, worked in the Main Physical (Geophysical) Observatory in Pavlovsk between 1917 and 1939 and then at the institute of civil air fleet in Leningrad. He studied possibilities of applying aerological data to the weather forecast. Molchanov constructed meteorographs, carried by sondes and aircraft and improved pilot observation technique. The radiosonde was first launched by him - on January 30, 1930. Named "271120", it was released 13:44 Moscow Time in Pavlovsk, USSR from the Main Geophysical Observatory and reached a height of 7.8 kilometers measuring temperature there (-40.7 °C). 32 minutes after the launch radiosonde sent the first aerological message to the Leningrad Weather Bureau and Moscow Central Forecast Institute. In July 1931, conducting programme of the International Polar Year, German scientists invited him to take part in an expedition into the Arctic onboard LZ 127 Graf Zeppelin and launch his radiosondes in polar latitudes. Twelve sondes were prepared for that purpose at Pavlovsk Observatory under Molchanov's leadership and successfully launched, conducting the first aerological observations in the Arctic. Molchanov also participated in first Soviet stratospheric balloon ascents (1933–34).
Since 1935 serial production of radiosondes was started in Leningrad. Molchanov's radiosonde construction was so perfect technically, that it was used until 1958 without any significant changes, providing sufficient accuracy of measurements, regularity and stability.
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