Assessment of occurrence and frequency of drought by percent normal precipitation index (PNPI) for western zone of Tamil Nadu

Abstract

Drought is a climatic variance, categorized by deficiency of rainfall, and high evaporation which cause negative consequences to environmental and human life. Understanding the drought is a significant process considering the current erratic rainfall situation. Nowadays monitoring the drought is a crucial factor for risk management and providing impact assessments to overcome from such drought events. A numerous drought index has been developed in many countries but they are not unique to all the region. This study examined Percent Normal Precipitation Index (PNPI) for Coimbatore and erode district in western zone of Tamil Nadu. A rainfall data was collected from 1971 to 2015 (45 years) for Coimbatore and Erode district and the Assessment of PNPI drought index was analyzed and result shows that both the district have slightly decreasing trends in drought events with increasing trends in heavy rainfall event. When analyzed agricultural drought it was occurred between 40 and 51 standard week in Coimbatore likewise for erode agricultural drought occurs in 45 and 50 standard weeks. This indicates effective real time contingency plans need to be formulated for managing the extreme weather conditions in western zone of Tamil Nadu.