Analysis of Rainfall Data for Arni Station

Yashwwanth Krishna Gunasekaran, Abhishek Senthil, Diwakaran Ramesh Babu

Rainfall is an important part of hydrological cycle and this proves to be a vital variable in dry-land areas. In order to develop an effective management it important to understand this resource by analyzing the data recorded by Indian Meteorological Society. In this study, monthly rainfall data from 1973-2002 is collected for Arni station, Thiruvannamalai district and observed. Analysis of yearly rainfall data is done and also analysis of variation of rainfall in time and amounts is performed. These analysis will help us in interpreting the rainfall variations among different seasons in the year.

The average yearly rainfall in Arni ranges from 80mm to 85mm in recent years. This results in scarcity of water which leads to problems in agricultural purposes. However during monsoon months ,which is from July to October, the average rainfall intensity ranges from 120mm- 175mm.Water resources in Arni are rare and the surface run-off is often low because of high evaporation rates. Although rainfall is a natural resource, but with the rainfall analysis data from past years can be really helpful in deduction of approximate rainfall data for the following years. Rain in excess is very rare in Arni although when it does occur it causes serious consequences such as flash flooding, human catastrophes and land degradation. From this analysis, the seasons such as Pre-Monsoon, Monsoon, Post-Monsoon and their variations are compared for three decades from1973-2002. Also the Maximum and Minimum rainfall intensity in these thirty years is also calculated.