Extending flood forecasting lead time in a large watershed by coupling WRF QPF with a distributed hydrological model
Long lead time flood forecasting is very important for large watershed flood mitigation as it provides more time for flood warning and emergency responses. The latest numerical weather forecast model could provide 1–15-day quantitative precipitation forecasting products in grid format, and...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-03-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/21/1279/2017/hess-21-1279-2017.pdf |
| Summary: | Long lead time flood forecasting is very important for large
watershed flood mitigation as it provides more time for flood warning and
emergency responses. The latest numerical weather forecast model could
provide 1–15-day quantitative precipitation forecasting products in grid
format, and by coupling this product with a distributed hydrological model
could produce long lead time watershed flood forecasting products. This paper
studied the feasibility of coupling the Liuxihe model with the Weather
Research and Forecasting quantitative precipitation forecast (WRF QPF) for large watershed flood forecasting in southern China. The QPF of WRF products has three lead times, including 24, 48 and 72 h, with the grid resolution being
20 km  × 20 km. The Liuxihe model is set up with freely downloaded terrain property; the model parameters were previously optimized with rain gauge observed precipitation, and re-optimized with the WRF QPF. Results show that the WRF QPF has bias with the rain gauge precipitation, and a
post-processing method is proposed to post-process the WRF QPF products,
which improves the flood forecasting capability. With model parameter
re-optimization, the model's performance improves also. This suggests that
the model parameters be optimized with QPF, not the rain gauge precipitation.
With the increasing of lead time, the accuracy of the WRF QPF decreases, as
does the flood forecasting capability. Flood forecasting products produced by
coupling the Liuxihe model with the WRF QPF provide a good reference for
large watershed flood warning due to its long lead time and rational results. |
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| ISSN: | 1027-5606 1607-7938 |