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

摘要

The temporal behavior of precipitation is more important in crop planning and prediction of extreme events. Salem District is one of the land-protected districts in Tamil Nadu. The main objectives of this study is to describe the temporal patterns ofrainfall amount and concentration of Salem District. The rainfall data for various locations and at different course of time were collected from Indian Meteorological Department (IMD) and analyzed to study the variability of rainfall in Salem district. It receives rainfall under influence of both southwest and northeast monsoons. It was observed that the maximum rainfall in the district was recorded in 2005 (1375 mm) and the minimum rainfall was recorded in 1980 (51 mm). It was also observed from the annual rainfall plot that the rainfall in the district is uneven. The overall 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). The station wise average rainfall analysis showed that that the Yercadu station has recorded the highest average annual rainfall ofl223.16mm compared to the other stations. The major contribution of rainfall to the district is from the South-west monsoon, which is about 42%, followed by the northeast, which is 38%. On an average, the north- east monsoon contributed a maximum of 306 mm to the total rainfall in the district and the minimum rainfall was recorded during the winter season. Between 1977 and 2012, the maximum rainfall was observed in2005 (1375. mm) which has its highest contribution from the northeast monsoon. In addition, the highest record of northeast monsoon /had been recorded in 2005 (712 mm). Around 20 years, the rainfall is lesser compared to the average annual rainfall (812mm).Hence, the district has not experienced any major distress with respect to rainfall as majority of years fall under normal category. This temporal variability analysis of rainfall in the district helps in crop planning and proposing water conservation activities.