It is shown that the occurrence of premonsoon thunderclouds (Nor' westers) in the neighbourhood of Calcutta is frequently associated with an increase in the integrated field intensity of atmospherics received on a frequency of 30 kc/s. © 1965.

A K SEN

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Enhancement of atmospherics associated with premonsoon thunderclouds

Journal of Atmospheric and Terrestrial Physics

Thunderstorm associated atmospherics during the monsoon, premonsoon and postmonsoon seasons over the tropical station Calcutta show some typical characteristics. In all the cases gradual rise of atmospherics (GRA) and steady recovery of atmospherics (SRA) have been found. In between the above two changes, there is the sudden enhancement of atmospherics (SEA) which is some times composed of two components SEA1 and SEA2. All the above facts of the integrated field intensity of atmospherics (IFIA) observed at 10 and 20 kHz have been critically examined here in relation to monsoon, premonsoon and postmonsoon thunderstorms. The results exhibit that the precipitation is associated with the steady recovery of IFIA during the monsoon and postmonsoon thunderstorms while that during premonsoon thunderstorms is associated with the second sudden enhancement. These anomalies have been interpreted in terms of charge separation within thunderclouds. Moreover, the difference of the respective amplitudes at 10 and 20 kHz of the different variations of IFIA have also been critically focussed. © 1980 Sprigner-Verlag.

Journal	Journal of Atmospheric and Terrestrial Physics
Publisher	-
ISSN	0021-9169