Impact Assessment of Uncertainty Propagation of Ensemble NWP Rainfall to Flood Forecasting with Catchment Scale. (5th January 2016)

• Record Type: Journal Article
• Authors: Yu, Wansik; Nakakita, Eiichi; Kim, Sunmin; Yamaguchi, Kosei
• Other Names: Gocic Milan Academic Editor.
• Is Part Of: Advances in meteorology. Volume 2016(2016)
• Publication Date: 2016-01-05
• Subjects: Meteorology -- Periodicals; Meteorology; Periodicals; 551.505
• DOI: 10.1155/2016/1384302
• Languages: English
• ISSNs: 1687-9309

Abstract

Abstract : The common approach to quantifying the precipitation forecast uncertainty is ensemble simulations where a numerical weather prediction (NWP) model is run for a number of cases with slightly different initial conditions. In practice, the spread of ensemble members in terms of flood discharge is used as a measure of forecast uncertainty due to uncertain precipitation forecasts. This study presents the uncertainty propagation of rainfall forecast into hydrological response with catchment scale through distributed rainfall-runoff modeling based on the forecasted ensemble rainfall of NWP model. At first, forecast rainfall error based on the BIAS is compared with flood forecast error to assess the error propagation. Second, the variability of flood forecast uncertainty according to catchment scale is discussed using ensemble spread. Then we also assess the flood forecast uncertainty with catchment scale using an estimation regression equation between ensemble rainfall BIAS and discharge BIAS. Finally, the flood forecast uncertainty with RMSE using specific discharge in catchment scale is discussed. Our study is carried out and verified using the largest flood event by typhoon "Talas" of 2011 over the 33 subcatchments of Shingu river basin (2, 360 km 2 ), which is located in the Kii Peninsula, Japan.