Author(s): Tao Peng, Haixia Qi, Junchao Wang

Linked Author(s): Tao Peng

Keywords: Precipitation ensemble forecast; Xin'anjiang model; Hydrological probabilistic forecast; The frequency analysis of flood peak;

Abstract: The ensemble precipitation forecasting provides a new idea for flood forecasting. The ensemble forecasting takes into account the uncertainty of initial field and model. A set of forecasting results can be obtained by inputting the ensemble precipitation forecasting products into hydrological model, which can avoid the misunderstanding of single deterministicnumerical forecasting results. Taking the typical flood process of Qingjiang basin in June 2016as an example, the flood forecast experiment was carried out based on the ensemble precipitation forecast products. Firstly, the basin flood forecast model was built on the Xin'anJiang hydrological Model, and the ensemble precipitation forecast product of the European Center for Medium-Range Weather Forecasting (ECMWF) was estimated and used to drive basin flood forecasting model. The results show that the 51 members of ECMWF ensemble forecast can better capture this rainstorm process, the cumulative precipitation and precipitation process for 72 hours is close to the observation. The precipitation ensemble forecast product drive the hydrological model, can provide more precipitation forecasting information than deterministic forecasting, enrich the input information of hydrological model,and then calculate and get the range of the flood peak and the arrival time of flood peak, and get the probability of flood occurrence in different amounts level through the frequency analysis of flood peak, solves the problem of the accuracy of the single forecast result, and transforms the single deterministic accurate forecast into the probabilistic forecast, which can better meet the demand of risk information for flood control and disaster reduction.

DOI: https://doi.org/10.3850/38WC092019-0599

Year: 2019