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Journal of Pharmacognosy and Phytochemistry

Journal of Pharmacognosy and Phytochemistry

Vol. 8, Special Issue 2 (2019)

Influence of El Niño and the Southern Oscillation (ENSO) on climate of Tamil Nadu

Author(s):

Gowtham R, Geethalakshmi V, Panneerselvam S, Bhuvaneswari K and Divya K

Abstract:
Tamil Nadu in India is located in the extreme south of the subcontinent, with normal annual rainfall of 945 mm, of which 48% is from the North East monsoon (October through December), and 32% from the South West monsoon (June through September). Gridded daily rainfall data at 0.5 x 0.5 degree resolution was obtained from IMD for a period of 1971 – 2005 and accumulated for Southwest and Northeast monsoon seasons over different river basins of Tamil Nadu. Historical SOI values were obtained from www.bom.gov.au/anon/home/ncc/www/sco/soi/soiplaintext.htmland the values were segregated into Neutral (-5.5>SOI <+ 5.5), El-Nino (SOI<-5.5), La-Nina (SOI>+5.5). Simultaneous correlation and lag correlation were performed between SOI / IOD and Rainfall. There is no significant correlation exist between El-Nino and SWM Rainfall at river basin scale. If the El-Nino events are segregated into weak and strong phases, then the strength of correlation is improved. Weak El-Nino years (SOI between -5.5 and -10) had positive correlation with SWM rainfall of southern, central and north-western parts of Tamil Nadu. In strong El-Nino years (SOI between -10 and -35), a positive correlation was observed in the eastern and north-eastern parts of Tamil Nadu as well as in most parts of the eastern coast. All La-Nina years had positive correlation with SWM rainfall over most parts of Western Ghats and northern coastal area. As far as NEM is concerned, only southern Tamil Nadu showed correlation up to 0.4 with El-Nino condition, while all other parts had weak correlation. Weak El-Nino years had good negative relationship with NEM rainfall over entire Western Ghats, east coast and northern pockets of Tamil Nadu.

Pages: 838-842  |  1125 Views  263 Downloads

How to cite this article:
Gowtham R, Geethalakshmi V, Panneerselvam S, Bhuvaneswari K and Divya K. Influence of El Niño and the Southern Oscillation (ENSO) on climate of Tamil Nadu. J Pharmacogn Phytochem 2019;8(2S):838-842.

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