FORECASTING ANNUAL RAINFALL DATA IN KARNATAKA USING ARMA MODEL AND CALCULATIONS OF EXCEEDANCE PROBABILITIES

The Karnataka gets significant amount of rainfall, which is influenced by the diversified topographical and climatic zones. There are mainly four climatic regions in Karnataka; one, Costal region, which receives highest average annual rainfall, o more than 3500 millimetres. Secondly, it is Malnad region, which gets an average annual rainfall of about 2000 millimetres. However, both the North Interior Karnataka and South Interior Karnataka Regions receive an average precipitation of about 700 millimetres respectively. This study analyses the annual rainfall trends in Karnataka from 1989 to 2023 and forecasts the expected rainfall for 2024-2028 using an Auto Regressive Moving Average Model (ARMA) - based on time series model. The analysis identifies historical fluctuations, seasonal variations, and the impact of extreme events on annual precipitation levels. The forecast suggests a gradual recovery in rainfall levels following a significant drop in 2023. The findings provide valuable insights for policymakers, agricultural planners, and water resource management authorities. The Statistical analysis of rainfall data using time series techniques is essential for understanding long-term trends, variability and predicting future patterns. This paper employs statistical and basic probability models to examine historical rainfall data, identify trends, and provide insights into rainfall variability in Karnataka.