Author(s): Chunguang Cui, Zhiyuan Yin, Tao Eng

Linked Author(s):

Keywords: Hydrometeorological coupled forecasting; WRF; TOPMODEL; SPECIAL SCALING EFFECT; Zhanghe River Basin;

Abstract: Based on the DEM topographic data of Zhanghe River reservoir in Jingmen, Hubei with the spatial resolution of 90m×90m, the work selected 20 flood processes from 2012 to 2015 (wherein 16 were for simulation, and 4 for test). The flood forecasting were tested by coupling the tripling-nested precipitation forecasting with the spatial resolutions of 3km×3km, 9km×9km and 27km×27km provided by the WRF in the Central China, the lumped Xin'anjiang model and the semi-distributed TOPMODEL. Through the comparison, the following conclusions were obtained: When the spatial and temporal distributions of precipitation in the basin were relatively uniform, the lumped Xin'anjiang model could accurately forecast the peak flow and peak appearance time; when there was large difference in the precipitation spatial and temporal distributions, the forecasting error increased accordingly. The TOPMODEL model based on DEM data reflected the difference of flood forecasting results under different precipitation spatial and temporal distributions. The test results showed that the output results of 3km×3km and 9km×9km flood forecasting were relatively close, and the forecasting accuracy and the relative error of flood peak were better than those of 27km×27km flood forecasting. On the time difference of peak appearance, the 27km×27km flood forecasting was in good agreement with the actual situation. It was also found that although there were some differences in the spatial and temporal distributions of precipitation in the basin, the WRF of three spatial resolutions could not forecast precipitation distribution in accordance with the actual data. However, in some cases, when the time distribution error and the spatial distribution error of precipitation were offset, more accurate flood forecasting results could still be obtained. Therefore, the precipitation forecasting of high spatial-temporal resolution does not contribute positively to flood forecasting, and it is necessary to repeatedly test for the optimal spatiotemporal resolution of hydrological model and numerical model coupling.

DOI: https://doi.org/10.3850/38WC092019-0623

Year: 2019