Verification of upper Citarum River discharge prediction using climate forecast system version 2 (CFSv2) output

Citarum River serves as a water supplier for the main reservoir in West Java, namely Saguling Reservoir. The river discharge prediction is important for reservoir operations and flood control. This study investigated the usefulness of Climate Forecast System Version 2 (CFSv2) data output to predict the Upper Citarum discharge. We statistically downscaled the CFSv2 output to derive the local climate prediction and then incorporated the result to hydrological model to obtain the discharge prediction. The statistical downscaling method used in this research is Multi Windows Constructed Analogue (CA) method using velocity potential (χ) and stream function (ψ) at 850 hPa as predictors and daily rainfall as predictand. The windows used are Australian Monsoon Index (AUSMI) and Western North Pacific Monsoon Index (WNPMI). The daily rainfall prediction was then used as an input for the Soil and Water Assessment Toll (SWAT) hydrological model to generate discharge prediction in the Upper Citarum basin. In this study, we investigated how well the prediction system predict low discharge event of