Spatial Analysis of Rainfall Variation in Dharmapuri District Tamilnadu using GIS

Among the climatic elements the rainfall is the first index, ever thought of by farmers and climatic analyzers as it is the most important single factor which determines the cropping pattern of an area in general and the type of crop to be cultivated and its success or failure in particular. It is therefore necessary to study the spatial and temporal variation of rainfall for judging the agricultural production potential and sustainability of agricultural production system. However, rainfall has one the highest spatial-temporal variability especially in mountain region where in addition, there is scarcity of information. Planning suitable measures for mitigating the problems requires through knowledge of the rainfall pattern. The present study was taken up to analyze the spatial and temporal variation of rainfall in study of Dharmapuri district, Tamil Nadu and India. These results were taken into geographical information system (GIS) platform to prepare the spatial distribution maps. The highest annual rainfall recorded in Dharmapuri 981.94 mm and lowest of rainfall is recorded in Perumbalai 622.80 mm. The annual variability ranges from24.13 per cent to 40.61 per cent. Month of October receives highest average rainfall (180.50 mm) and the month of January receives the minimum with an average of 8.00 mm. The study concludes that the Dharmapuri district receives maximum amount of rainfall receive only South west monsoon (June-September) over the last 34 years.