LAUSR

This study investigates the use of Tropical Rainfall Measurement Mission's (TRMM) rainfall data for predicting water flows and flood events in three catchments on the island of Java, Indonesia, namely, Ciliwung, Citarum and Bengawan Solo. The Shetran model has used for rainfall–runoff simulations, with rainfall input obtained from measured rain gauges (hourly and daily) and TRMM (3 h and daily). Separate model calibrations and validations were carried out. The Nash Sutcliffe Efficiency (NSE) values of the models using rain gauge data for the three catchments for the calibration period were 0.75, 0.70 and 0.85 and using the TRMM rainfall data were 0.44, 0.44 and 0.75. The NSE values were 0.71, 0.62 and 0.89 for the validation period using rain gauge data and 0.26, 0.61 and 0.58 for the TRMM data. The Critical Success Index for predicting flooding events was improved using rain gauge data compared to using TRMM data. The results demonstrate that rain gauge data are systematically superior to TRMM rainfall data when used for simulating discharges and predicting flooding events. These findings suggest that rain gauge data are preferred for flood early warning systems in tropical rainfall regimes and that if TRMM or similar satellite rainfall data are used, the evaluated flood risks should be treated with extreme caution.