A Method to Account for QPF Spatial Displacement Errors in Short-Term Ensemble Streamflow Forecasting
Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA 50011, USA
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Water 2020, 12(12), 3505; https://doi.org/10.3390/w12123505
Received: 10 September 2020
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Revised: 4 December 2020
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Accepted: 7 December 2020
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Published: 13 December 2020
(This article belongs to the Special Issue Hydrometeorological Forecasting Using the Weather Research and Forecasting Model)
To account for spatial displacement errors common in quantitative precipitation forecasts (QPFs), a method using systematic shifting of QPF fields was tested to create ensemble streamflow forecasts. While previous studies addressed spatial displacement using neighborhood approaches, shifting of QPF accounts for those errors while maintaining the structure of predicted systems, a feature important in hydrologic forecasts. QPFs from the nine-member High-Resolution Rapid Refresh Ensemble were analyzed for 46 forecasts from 6 cases covering 17 basins within the National Weather Service North Central River Forecast Center forecasting region. Shifts of 55.5 and 111 km were made in the four cardinal and intermediate directions, increasing the ensemble size to 81 members. These members were input into a distributed hydrologic model to create an ensemble streamflow prediction. Overall, the ensemble using the shifted QPFs had an improved frequency of non-exceedance and probability of detection, and thus better predicted flood occurrence. However, false alarm ratio did not improve, likely because shifting multiple QPF ensembles increases the potential to place heavy precipitation in a basin where none actually occurred. A weighting scheme based on a climatology of displacements was tested, improving overall performance slightly compared to the approach using non-weighted members.
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Keywords:
ensemble streamflow prediction; flood forecasting; quantitative precipitation forecasts; spatial displacement errors
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MDPI and ACS Style
Carlberg, B.; Franz, K.; Gallus, W., Jr. A Method to Account for QPF Spatial Displacement Errors in Short-Term Ensemble Streamflow Forecasting. Water 2020, 12, 3505. https://doi.org/10.3390/w12123505
AMA Style
Carlberg B, Franz K, Gallus W Jr. A Method to Account for QPF Spatial Displacement Errors in Short-Term Ensemble Streamflow Forecasting. Water. 2020; 12(12):3505. https://doi.org/10.3390/w12123505
Chicago/Turabian StyleCarlberg, Bradley, Kristie Franz, and William Gallus Jr. 2020. "A Method to Account for QPF Spatial Displacement Errors in Short-Term Ensemble Streamflow Forecasting" Water 12, no. 12: 3505. https://doi.org/10.3390/w12123505
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