Seasonal Rainfall Forecast Verification Analysis for Vridhachalam, Tamil Nadu, India

Abstract

Seasonal rainfall patterns play a vital role in shaping agricultural practices, crop yields and water resource management in various regions. In the context of Virdhachalam Block, Cuddalore District, accurate forecasts of seasonal rainfall are crucial for successful crop sowing, farm operations and overall agricultural planning. To address the significance of reliable rainfall predictions, this study examined the forecast accuracy of four different seasons (northeast monsoon, winter, summer and southwest monsoon), using various metrics such as forecast accuracy ratio, critical success index, true skill score and false alarm ratio for Virdhachalam block, Cuddalore district. The results showed that the summer season had the highest forecast accuracy (0.76) followed by winter (0.69), northeast monsoon (0.63) and southwest monsoon (0.66). However, the critical success index was highest during northeast monsoon (0.48) followed by southwest monsoon (0.38), winter (0.36) and summer (0.27) indicating a higher rate of correct rainfall prediction with fewer false alarms. The true skill score index was highest during summer, while the false alarm ratio was highest in summer as well as winter. These findings highlight the need for improving forecast accuracy during the monsoon season to ensure successful crop sowing and farm operations, while also emphasizing the importance of accurate forecasts during winter and summer to prevent crop failures and aid in soil water conservation for subsequent crops. Furthermore, the study found that accurate forecasts during the northeast monsoon and southwest monsoon could lead to better planning and management of agricultural activities resulting in improved yields and profits for farmers.