Rainfall Forecast Verification in Different Blocks of Banka District of Bihar

Abstract

Accuracy in rainfall forecast plays an important role in farming operations. Here, a study has been done to verify the forecast and actual rainfall data of 11 blocks of Banka district at KVK, Banka. To verify the accuracy of rainfall forecast for the financial year 2020-21 several statistical tools has been used i.e., Forecast Accuracy (ACC) or Ratio Score or Hit Score, Hanssen and Kuipers Scores or True Skill Score (HK score), Probability of detection (POD), Heidke Skill Score (HSS), False alarm ratio, Critical Success index (CSI), Missing Rate (MR) and BIAS score. Forecast Accuracy (ACC) ranged from 0.81 to 0.87 and the highest accuracy of rainfall prediction was observed in Katoriya block and lowest accuracy observed in Amarpur, Dhoraiya and Rajoun block. Similarly, Critical Success Index (CSI) was recorded with the values range of 0.4 to 0.6 for respective blocks of Banka district. Heidke Skill Score (HSS) was accounted as 0.50 for Amarpur, Banka, Barahat, Bounsi, Belhar, Dhoraiya, Rajoun and Shambhuganj and for rest of the blocks it was 0.6. The higher accuracy (87.1 per cent) was recorded in Katoriya block followed by Fullidumar (86.3 per cent) and Chandan (85.4 per cent). The highest no. of rainy days was observed in Katoriya block (75 no.) followed by Chandan (74 no.). POD value ranges between 0.8-0.9, FAR value between 0.3-0.5, MR and BIAS value ranges between 0.8-0.9 and 1.3 -2.0 respectively.