Observations Made By the Ionospheric Institute of Athens During the Series of Nuclear Weapon Tests at Novaja Zemlya Between 10 September and 4 November 1961

During the last period of Russian nuclear weapon tests, the Ionospheric Institute of the National Observatory of Athens, noticed several phenomena in the upper and lower atmosphere, over Athens. According to our calculations, the test range was Novaja Zemlya, in the North of Russia, at a distance of about 4390 km from Athens. Obviously, this long distance creates poor conditions for clear observation. In fact, among the nuclear explosions that have taken place between 10 September 1961 and 4 November 1961, only two give evidence of a distance ionospheric disturbance (23 October and 30 October), as measured in Athens. The explosion of 30 October has also been recorded by the microbarographs in Greece. An increase of radioactive fallout due to the nuclear weapon tests, will also be treated in the present contribution.