nerc.ac.uk

Evaluating the impact of post-processing medium-range ensemble streamflow forecasts from the European Flood Awareness System

Matthews, Gwyneth; Barnard, Christopher; Cloke, Hannah; Dance, Sarah L.; Jurlina, Toni; Mazzetti, Cinzia; Prudhomme, Christel. 2022 Evaluating the impact of post-processing medium-range ensemble streamflow forecasts from the European Flood Awareness System. Hydrology and Earth System Sciences, 26 (11). 2939-2968. 10.5194/hess-26-2939-2022

Before downloading, please read NORA policies.
[thumbnail of N532801JA.pdf]
Preview
Text
N532801JA.pdf - Published Version
Available under License Creative Commons Attribution 4.0.

Download (6MB) | Preview

Abstract/Summary

Streamflow forecasts provide vital information to aid emergency response preparedness and disaster risk reduction. Medium-range forecasts are created by forcing a hydrological model with output from numerical weather prediction systems. Uncertainties are unavoidably introduced throughout the system and can reduce the skill of the streamflow forecasts. Post-processing is a method used to quantify and reduce the overall uncertainties in order to improve the usefulness of the forecasts. The post-processing method that is used within the operational European Flood Awareness System is based on the model conditional processor and the ensemble model output statistics method. Using 2 years of reforecasts with daily timesteps, this method is evaluated for 522 stations across Europe. Post-processing was found to increase the skill of the forecasts at the majority of stations in terms of both the accuracy of the forecast median and the reliability of the forecast probability distribution. This improvement is seen at all lead times (up to 15 d) but is largest at short lead times. The greatest improvement was seen in low-lying, large catchments with long response times, whereas for catchments at high elevation and with very short response times the forecasts often failed to capture the magnitude of peak flows. Additionally, the quality and length of the observational time series used in the offline calibration of the method were found to be important. This evaluation of the post-processing method, and specifically the new information provided on characteristics that affect the performance of the method, will aid end users in making more informed decisions. It also highlights the potential issues that may be encountered when developing new post-processing methods.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.5194/hess-26-2939-2022
UKCEH and CEH Sections/Science Areas: UKCEH Fellows
ISSN: 1027-5606
Additional Information. Not used in RCUK Gateway to Research.: Open Access paper - full text available via Official URL link.
NORA Subject Terms: Hydrology
Date made live: 24 Jun 2022 16:36 +0 (UTC)
URI: https://nora.nerc.ac.uk/id/eprint/532801

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...