Discussion for the Effectiveness of Radar Data through Distributed Storm Runoff Modeling

This study is to evaluate the use of dual-polarization radar data for storm runoff modeling in Namgang dam (2,293 km² ) watershed using KIMSTORM (Grid-based KIneMatic wave STOrm Runoff Model). The Bisl dual-polarization radar data for 3 typhoons (Khanun, Bolaven, Sanba) and 1 heavy rain event in 2012 were obtained from Han River Flood Control Office. Even the radar data were overall less than the ground data in areal average, the spatio-temporal pattern between the two data was good showing the coefficient of determination ( R² ) and bias with 0.97 and 0.84 respectively. For the case of heavy rain, the radar data caught the rain passing through the ground stations. The KIMSTORM was set to 500×500 m resolution and a total of 21,372 cells (156 rows × 137 columns) for the watershed. Using 28 ground rainfall data, the model was calibrated using discharge data at 5 stations with R² , Nash and Sutcliffe Model Efficiency (ME) and Volume Conservation Index (VCI) with 0.85, 0.78 and 1.09 respectively. The calibration results by radar rainfall showed R² , ME and VCI were 0.85, 0.79, and 1.04 respectively. The VCI by radar data was enhanced by 5 %.