Abstract

Retrospective analysis of north east monsoon rainfall climatology in respect of Tamil Nadu indicated the following (1) Lesser than Tamil Nadu NEM average rainfall with higher CV's were recorded for North Arcot, Salem, Dharmapuri, Coimbatore, Periyar, Trichy, Pudukkottai and Madurai districts, whereas Chennai and Chengalput districts recorded above normal rainfall with lower CV values; (2) In all the districts of Tamil Nadu, 60-70% of years were under within one standard deviation (3) In 80% of El- Nino years, Thanjavur and Chengalput districts had shown above normal rainfall while Madurai, North Arcot, Dharmpuri and Coimbatore districts did exhibit such events in only 60% of El-Nino years.

Keywords: NEM rainfall, Coefficient of variation, El-Nino, Tamil Nadu