Temporal Variability in the Precipitation Concentration at Salem District of Tamil Nadu

Abstract

The temporal behavior of precipitation is more important in crop planningand prediction of extreme events. Salem District is one of the land-protecteddistricts in Tamil Nadu. The main objectives of this study is to describe thetemporal patterns of rainfall amount and concentration of Salem District.The rainfall data for various locations and at different course of time werecollected from Indian Meteorological Department (IMD) and analyzed tostudy the variability of rainfall in Salem district. It receives rainfall underinfluence of both southwest and northeast monsoons. It was observed thatthe maximum rainfall in the district was recorded in 2005 (1375 mm) andthe minimum rainfall was recorded in 1980 (51 mm). It was also observedfrom the annual rainfall plot that the rainfall in the district is uneven. Theoverall average annual rainfall of the district over the years is around 81 mm.The maximum number of rainy days was recorded in 2010 (91 days). Thestation wise average rainfall analysis showed that that the Yercadu stationhas recorded the highest average annual rainfall of1223.16mm compared tothe other stations. The major contribution of rainfall to the district is from theSouth-west monsoon, which is about 42%, followed by the northeast, whichis 38%. On an average, the north- east monsoon contributed a maximumof 306 mm to the total rainfall in the district and the minimum rainfall wasrecorded during the winter season. Between 1977 and 2012, the maximumrainfall was observed in 2005 (1375. mm) which has its highest contributionfrom the northeast monsoon. In addition, the highest record of northeastmonsoon had been recorded in 2005 (712 mm). Around 20 years, therainfall is lesser compared to the average annual rainfall (812 mm).Hence,the district has not experienced any major distress with respect to rainfallas majority of years fall under normal category. This temporal variabilityanalysis of rainfall in the district helps in crop planning and proposing waterconservation activities.